{
 "name": "AskCalc",
 "generated": "2026-10-15",
 "count": 206,
 "calculators": [
  {
   "id": "gout-acr-eular-2015",
   "name": "2015 ACR/EULAR Gout Classification Criteria",
   "short": "Gout criteria 2015",
   "category": "Endocrine & Metabolic",
   "url": "https://askcalc.site/calc/gout-acr-eular-2015/",
   "summary": "For patients with at least one episode of peripheral joint or bursa swelling, pain or tenderness, MSU crystals in synovial fluid or a tophus classify gout outright; otherwise a weighted score of clinical, serum urate and imaging items is summed (range −6 to 23), and ≥8 classifies as gout (sensitivity 92%, specificity 89%).",
   "formula": "Entry: ≥1 episode of peripheral joint/bursa swelling, pain or tenderness. Sufficient: MSU crystals in symptomatic joint/bursa or tophus. Otherwise sum: joint pattern (ankle/midfoot 1, 1st MTP 2) + episode characteristics (erythema, can't bear touch, great difficulty walking: 1 each) + time course (1 typical episode 1, recurrent 2) + tophus 4 + serum urate (<4 mg/dL −4; 4–<6: 0; 6–<8: 2; 8–<10: 3; ≥10: 4) + synovial fluid MSU negative −2 + imaging urate deposition 4 + radiographic erosion 4. Gout if ≥8.",
   "inputs": [
    {
     "id": "msu",
     "label": "Synovial fluid / tophus aspirate for MSU crystals",
     "kind": "sel",
     "options": [
      {
       "value": "not_done",
       "label": "Not done",
       "points": 0
      },
      {
       "value": "negative",
       "label": "MSU negative (symptomatic joint/bursa)",
       "points": -2
      },
      {
       "value": "positive",
       "label": "MSU positive (sufficient criterion)"
      }
     ],
     "optional": true
    },
    {
     "id": "pattern",
     "label": "Joints/bursae involved in symptomatic episode(s) ever",
     "kind": "sel",
     "options": [
      {
       "value": "other",
       "label": "Other joints/bursae only, or ankle/midfoot/1st MTP only as part of a polyarticular presentation",
       "points": 0
      },
      {
       "value": "ankle_midfoot",
       "label": "Ankle or midfoot (mono/oligoarticular) without 1st MTP",
       "points": 1
      },
      {
       "value": "mtp1",
       "label": "First MTP joint (mono/oligoarticular)",
       "points": 2
      }
     ]
    },
    {
     "id": "erythema",
     "label": "Erythema overlying the affected joint (ever)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "cant_touch",
     "label": "Can't bear touch or pressure to the affected joint (ever)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "walking",
     "label": "Great difficulty walking or inability to use the affected joint (ever)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "time_course",
     "label": "Typical episodes (≥2 of: max pain <24 h, resolution ≤14 days, complete resolution between episodes)",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "No typical episodes",
       "points": 0
      },
      {
       "value": "one",
       "label": "One typical episode",
       "points": 1
      },
      {
       "value": "recurrent",
       "label": "Recurrent typical episodes",
       "points": 2
      }
     ]
    },
    {
     "id": "tophus",
     "label": "Clinical tophus (draining or chalk-like subcutaneous nodule in a typical location)",
     "kind": "yn",
     "points": 4
    },
    {
     "id": "urate",
     "label": "Serum urate (highest off urate-lowering therapy)",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L",
      "mmol/L"
     ],
     "min": 0.5,
     "max": 25
    },
    {
     "id": "imaging_urate",
     "label": "Imaging urate deposition: ultrasound double-contour sign or DECT urate (not done = no)",
     "kind": "yn",
     "points": 4,
     "optional": true
    },
    {
     "id": "erosion",
     "label": "Radiographic gout erosion of hands/feet (not done = no)",
     "kind": "yn",
     "points": 4,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Neogi T et al. 2015 Gout classification criteria: an American College of Rheumatology/European League Against Rheumatism collaborative initiative. Ann Rheum Dis 2015;74:1789–98.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/26359487/"
    },
    {
     "title": "Neogi T et al. 2015 Gout classification criteria. Arthritis Rheumatol 2015;67:2557–68.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/26352873/"
    }
   ]
  },
  {
   "id": "four-at",
   "name": "4AT Rapid Delirium Screen",
   "short": "4AT",
   "category": "Neurology",
   "url": "https://askcalc.site/calc/four-at/",
   "summary": "The 4AT (0–12) screens for delirium using Alertness, AMT4, Attention (months backwards) and Acute change/fluctuation. ≥4 suggests possible delirium ± cognitive impairment; 1–3 possible cognitive impairment; 0 makes delirium or severe cognitive impairment unlikely.",
   "formula": "Alertness: normal 0, abnormal 4 · AMT4: 0 mistakes 0, 1 mistake 1, ≥2/untestable 2 · Months backwards: ≥7 correct 0, <7 or refuses 1, untestable 2 · Acute change/fluctuation: no 0, yes 4. Total 0–12.",
   "inputs": [
    {
     "id": "alertness",
     "label": "1. Alertness",
     "kind": "sel",
     "options": [
      {
       "value": "normal",
       "label": "Normal (fully alert, not agitated) or mild sleepiness <10 s after waking",
       "points": 0
      },
      {
       "value": "altered",
       "label": "Clearly abnormal (drowsy, agitated, hyperactive)",
       "points": 4
      }
     ]
    },
    {
     "id": "amt4",
     "label": "2. AMT4 (age, date of birth, place, current year)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No mistakes",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 mistake",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 or more mistakes / untestable",
       "points": 2
      }
     ]
    },
    {
     "id": "attention",
     "label": "3. Attention: months of the year backwards",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Achieves 7 months or more correctly",
       "points": 0
      },
      {
       "value": "1",
       "label": "Starts but scores <7 months, or refuses to start",
       "points": 1
      },
      {
       "value": "2",
       "label": "Untestable (cannot start: unwell, drowsy, inattentive)",
       "points": 2
      }
     ]
    },
    {
     "id": "acute",
     "label": "4. Acute change or fluctuating course",
     "kind": "sel",
     "options": [
      {
       "value": "no",
       "label": "No",
       "points": 0
      },
      {
       "value": "yes",
       "label": "Yes (in alertness, cognition or other mental function, within last 2 weeks and still evident in last 24 h)",
       "points": 4
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Bellelli G et al. Validation of the 4AT, a new instrument for rapid delirium screening: a study in 234 hospitalised older people. Age Ageing 2014;43:496–502.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/24590568/"
    }
   ]
  },
  {
   "id": "four-ts-hit",
   "name": "4Ts Score for Heparin-Induced Thrombocytopenia",
   "short": "4Ts",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/four-ts-hit/",
   "summary": "The 4Ts score estimates pretest probability of heparin-induced thrombocytopenia from Thrombocytopenia, Timing, Thrombosis and oTher causes (0–8). A score of 0–3 is low probability (HIT effectively ruled out), 4–5 intermediate and 6–8 high; test and stop heparin when intermediate or high.",
   "formula": "Sum of 4 items, each 0–2: Thrombocytopenia + Timing + Thrombosis + oTher causes (max 8).",
   "inputs": [
    {
     "id": "thrombocytopenia",
     "label": "Thrombocytopenia",
     "kind": "sel",
     "options": [
      {
       "value": "2",
       "label": "Platelet fall > 50% and nadir ≥ 20 ×10⁹/L",
       "points": 2
      },
      {
       "value": "1",
       "label": "Platelet fall 30–50% or nadir 10–19 ×10⁹/L",
       "points": 1
      },
      {
       "value": "0",
       "label": "Platelet fall < 30% or nadir < 10 ×10⁹/L",
       "points": 0
      }
     ]
    },
    {
     "id": "timing",
     "label": "Timing of platelet fall",
     "kind": "sel",
     "options": [
      {
       "value": "2",
       "label": "Clear onset day 5–10, or fall ≤ 1 day with heparin exposure in past 30 days",
       "points": 2
      },
      {
       "value": "1",
       "label": "Consistent with day 5–10 but unclear (missing counts), onset after day 10, or fall ≤ 1 day with heparin 30–100 days ago",
       "points": 1
      },
      {
       "value": "0",
       "label": "Fall < 4 days without recent heparin exposure",
       "points": 0
      }
     ]
    },
    {
     "id": "thrombosis",
     "label": "Thrombosis or other sequelae",
     "kind": "sel",
     "options": [
      {
       "value": "2",
       "label": "New thrombosis (confirmed), skin necrosis at injection site, or acute systemic reaction after IV heparin bolus",
       "points": 2
      },
      {
       "value": "1",
       "label": "Progressive or recurrent thrombosis, non-necrotizing skin lesions, or suspected thrombosis not yet proven",
       "points": 1
      },
      {
       "value": "0",
       "label": "None",
       "points": 0
      }
     ]
    },
    {
     "id": "other_cause",
     "label": "Other causes of thrombocytopenia",
     "kind": "sel",
     "options": [
      {
       "value": "2",
       "label": "None apparent",
       "points": 2
      },
      {
       "value": "1",
       "label": "Possible other cause",
       "points": 1
      },
      {
       "value": "0",
       "label": "Definite other cause",
       "points": 0
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Lo GK et al. Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings. J Thromb Haemost 2006;4:759–65.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16634744/"
    }
   ]
  },
  {
   "id": "abc-massive-transfusion",
   "name": "ABC Score for Massive Transfusion",
   "short": "ABC Score",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/abc-massive-transfusion/",
   "summary": "The ABC (Assessment of Blood Consumption) score gives 1 point each for penetrating mechanism, ED SBP ≤90 mmHg, ED heart rate ≥120 and positive FAST. A score ≥2 predicts massive transfusion (75% sensitive, 86% specific in derivation).",
   "formula": "Penetrating mechanism 1 · ED SBP ≤90 mmHg 1 · ED HR ≥120 1 · Positive FAST 1. Score ≥2 → predicts MT.",
   "inputs": [
    {
     "id": "penetrating",
     "label": "Penetrating mechanism",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "sbp",
     "label": "ED arrival systolic BP",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "hr",
     "label": "ED arrival heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "fast",
     "label": "Positive FAST exam",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Nunez TC et al. Early prediction of massive transfusion in trauma: simple as ABC (assessment of blood consumption)? J Trauma 2009;66:346–52.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/19204506/"
    }
   ]
  },
  {
   "id": "abcd2",
   "name": "ABCD² Score for TIA",
   "short": "ABCD²",
   "category": "Neurology",
   "url": "https://askcalc.site/calc/abcd2/",
   "summary": "ABCD² (0–7) estimates early stroke risk after TIA from Age, Blood pressure, Clinical features, Duration and Diabetes. 2-day stroke risk in the derivation cohorts: 0–3 low (1.0%), 4–5 moderate (4.1%), 6–7 high (8.1%).",
   "formula": "Age ≥60: 1 · BP ≥140/90 at first assessment: 1 · Unilateral weakness 2, speech disturbance without weakness 1 · Duration ≥60 min 2, 10–59 min 1 · Diabetes 1",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "sbp",
     "label": "First systolic BP after TIA",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "dbp",
     "label": "First diastolic BP after TIA",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 20,
     "max": 200
    },
    {
     "id": "clinical",
     "label": "Clinical features",
     "kind": "sel",
     "options": [
      {
       "value": "weakness",
       "label": "Unilateral weakness",
       "points": 2
      },
      {
       "value": "speech",
       "label": "Speech disturbance without weakness",
       "points": 1
      },
      {
       "value": "other",
       "label": "Other symptoms",
       "points": 0
      }
     ]
    },
    {
     "id": "duration",
     "label": "Duration of symptoms",
     "kind": "sel",
     "options": [
      {
       "value": "60",
       "label": "≥ 60 minutes",
       "points": 2
      },
      {
       "value": "10",
       "label": "10–59 minutes",
       "points": 1
      },
      {
       "value": "0",
       "label": "< 10 minutes",
       "points": 0
      }
     ]
    },
    {
     "id": "dm",
     "label": "Diabetes",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Johnston SC et al. Validation and refinement of scores to predict very early stroke risk after transient ischaemic attack. Lancet 2007;369:283–92.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/17258668/"
    }
   ]
  },
  {
   "id": "abic",
   "name": "ABIC Score (Alcoholic Hepatitis)",
   "short": "ABIC",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/abic/",
   "summary": "ABIC = 0.1 × age + 0.08 × bilirubin (mg/dL) + 0.3 × creatinine (mg/dL) + 0.8 × INR. It stratifies 90-day survival in alcohol-associated hepatitis: <6.71 low risk (~100%), 6.71–8.99 intermediate (~70%), ≥9.0 high risk (~25%).",
   "formula": "ABIC = (age × 0.1) + (bilirubin mg/dL × 0.08) + (creatinine mg/dL × 0.3) + (INR × 0.8)",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "inr",
     "label": "INR",
     "kind": "num",
     "min": 0.5,
     "max": 20
    }
   ],
   "references": [
    {
     "title": "Dominguez M et al. A new scoring system for prognostic stratification of patients with alcoholic hepatitis. Am J Gastroenterol 2008;103:2747–56.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18721242/"
    }
   ]
  },
  {
   "id": "anc",
   "name": "Absolute Neutrophil Count (ANC)",
   "short": "ANC",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/anc/",
   "summary": "ANC = WBC × (% segmented neutrophils + % bands) ÷ 100. Neutropenia is ANC <1500/µL: mild 1000–1499, moderate 500–999, severe <500 (profound <100), which defines high infection risk and febrile neutropenia.",
   "formula": "ANC (cells/µL) = WBC (×10³/µL) × 1000 × (% segs + % bands) ÷ 100",
   "inputs": [
    {
     "id": "wbc",
     "label": "White blood cell count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 500
    },
    {
     "id": "segs",
     "label": "Segmented neutrophils",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0,
     "max": 100
    },
    {
     "id": "bands",
     "label": "Band neutrophils",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0,
     "max": 100,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Newburger PE, Dale DC. Evaluation and management of patients with isolated neutropenia. Semin Hematol 2013;50:198–206.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/23953336/"
    }
   ]
  },
  {
   "id": "adjusted-body-weight",
   "name": "Adjusted Body Weight (Dosing Weight)",
   "short": "AdjBW",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/adjusted-body-weight/",
   "summary": "Adjusted body weight = IBW + 0.4 × (actual weight − IBW), used for dosing drugs such as aminoglycosides and for Cockcroft-Gault in obesity, typically when actual weight exceeds 120% of IBW.",
   "formula": "AdjBW = IBW + 0.4 × (TBW − IBW); IBW (Devine) = 50 (men) / 45.5 (women) + 2.3 × (inches over 60)",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 20,
     "max": 400
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 100,
     "max": 250
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Traynor AM, Nafziger AN, Bertino JS Jr. Aminoglycoside dosing weight correction factors for patients of various body sizes. Antimicrob Agents Chemother 1995;39:545–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/7726530/"
    },
    {
     "title": "Pai MP, Paloucek FP. The origin of the \"ideal\" body weight equations. Ann Pharmacother 2000;34:1066–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10981254/"
    }
   ]
  },
  {
   "id": "asrs-v1-1-screener",
   "name": "Adult ADHD Self-Report Scale (ASRS v1.1) Screener, Part A",
   "short": "ASRS v1.1",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/asrs-v1-1-screener/",
   "summary": "The WHO ASRS v1.1 Screener asks 6 questions about ADHD symptoms over the past 6 months. Items 1–3 count as positive at \"Sometimes\" or more often and items 4–6 at \"Often\" or more often; 4 or more positive items means symptoms highly consistent with adult ADHD and further evaluation is warranted.",
   "formula": "Six items rated Never / Rarely / Sometimes / Often / Very Often for the past 6 months. Items 1–3 are positive at Sometimes, Often or Very Often; items 4–6 are positive at Often or Very Often. Count positive (darkly shaded) items, 0–6; ≥4 is a positive screen.",
   "inputs": [
    {
     "id": "q1",
     "label": "How often do you have trouble wrapping up the final details of a project, once the challenging parts have been done?",
     "kind": "sel",
     "options": [
      {
       "value": "never",
       "label": "Never"
      },
      {
       "value": "rarely",
       "label": "Rarely"
      },
      {
       "value": "sometimes",
       "label": "Sometimes"
      },
      {
       "value": "often",
       "label": "Often"
      },
      {
       "value": "very_often",
       "label": "Very Often"
      }
     ]
    },
    {
     "id": "q2",
     "label": "How often do you have difficulty getting things in order when you have to do a task that requires organization?",
     "kind": "sel",
     "options": [
      {
       "value": "never",
       "label": "Never"
      },
      {
       "value": "rarely",
       "label": "Rarely"
      },
      {
       "value": "sometimes",
       "label": "Sometimes"
      },
      {
       "value": "often",
       "label": "Often"
      },
      {
       "value": "very_often",
       "label": "Very Often"
      }
     ]
    },
    {
     "id": "q3",
     "label": "How often do you have problems remembering appointments or obligations?",
     "kind": "sel",
     "options": [
      {
       "value": "never",
       "label": "Never"
      },
      {
       "value": "rarely",
       "label": "Rarely"
      },
      {
       "value": "sometimes",
       "label": "Sometimes"
      },
      {
       "value": "often",
       "label": "Often"
      },
      {
       "value": "very_often",
       "label": "Very Often"
      }
     ]
    },
    {
     "id": "q4",
     "label": "When you have a task that requires a lot of thought, how often do you avoid or delay getting started?",
     "kind": "sel",
     "options": [
      {
       "value": "never",
       "label": "Never"
      },
      {
       "value": "rarely",
       "label": "Rarely"
      },
      {
       "value": "sometimes",
       "label": "Sometimes"
      },
      {
       "value": "often",
       "label": "Often"
      },
      {
       "value": "very_often",
       "label": "Very Often"
      }
     ]
    },
    {
     "id": "q5",
     "label": "How often do you fidget or squirm with your hands or feet when you have to sit down for a long time?",
     "kind": "sel",
     "options": [
      {
       "value": "never",
       "label": "Never"
      },
      {
       "value": "rarely",
       "label": "Rarely"
      },
      {
       "value": "sometimes",
       "label": "Sometimes"
      },
      {
       "value": "often",
       "label": "Often"
      },
      {
       "value": "very_often",
       "label": "Very Often"
      }
     ]
    },
    {
     "id": "q6",
     "label": "How often do you feel overly active and compelled to do things, like you were driven by a motor?",
     "kind": "sel",
     "options": [
      {
       "value": "never",
       "label": "Never"
      },
      {
       "value": "rarely",
       "label": "Rarely"
      },
      {
       "value": "sometimes",
       "label": "Sometimes"
      },
      {
       "value": "often",
       "label": "Often"
      },
      {
       "value": "very_often",
       "label": "Very Often"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Kessler RC et al. The World Health Organization Adult ADHD Self-Report Scale (ASRS): a short screening scale for use in the general population. Psychol Med 2005;35:245–56.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/15841682/"
    },
    {
     "title": "NYU Langone. ASRS v1.1 6-Question Screener: licensing and attribution.",
     "url": "https://license.tov.med.nyu.edu/product/asrs6Qscreener"
    }
   ]
  },
  {
   "id": "age-adjusted-d-dimer",
   "name": "Age-Adjusted D-dimer Cutoff for Pulmonary Embolism",
   "short": "Age-adjusted D-dimer",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/age-adjusted-d-dimer/",
   "summary": "In patients older than 50 with non-high (or \"PE unlikely\") clinical probability, the D-dimer cutoff for excluding PE is age × 10 µg/L FEU (ng/mL) instead of the fixed 500 µg/L. A D-dimer below the age-adjusted cutoff rules out PE without imaging (ADJUST-PE 3-month failure rate 0.3%).",
   "formula": "Cutoff (µg/L FEU) = age × 10 if age > 50, otherwise 500. 1 mg/L FEU = 1000 µg/L = 1000 ng/mL.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "ddimer",
     "label": "D-dimer (FEU)",
     "kind": "num",
     "unit": "ng/mL",
     "units": [
      "ng/mL",
      "µg/L",
      "mg/L"
     ],
     "min": 10,
     "max": 100000,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Righini M et al. Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study. JAMA 2014;311:1117–24.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/24643601/"
    }
   ]
  },
  {
   "id": "aims65",
   "name": "AIMS65 Score for Upper GI Bleeding",
   "short": "AIMS65",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/aims65/",
   "summary": "AIMS65 predicts in-hospital mortality in upper GI bleeding with one point each for albumin <3.0 g/dL, INR >1.5, altered mental status, systolic BP ≤90 mmHg and age ≥65. Mortality rises from 0.3% at 0 to 31.8% at 5; a score ≥2 marks high risk.",
   "formula": "One point each: Albumin <3.0 g/dL (<30 g/L) · INR >1.5 · altered Mental status · Systolic BP ≤90 mmHg · age ≥65",
   "inputs": [
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 7
    },
    {
     "id": "inr",
     "label": "INR",
     "kind": "num",
     "min": 0.5,
     "max": 20
    },
    {
     "id": "ams",
     "label": "Altered mental status (GCS <14, disorientation, lethargy)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 16,
     "max": 120
    }
   ],
   "references": [
    {
     "title": "Saltzman JR et al. A simple risk score accurately predicts in-hospital mortality, length of stay, and cost in acute upper GI bleeding. Gastrointest Endosc 2011;74:1215–24.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/21907980/"
    }
   ]
  },
  {
   "id": "albi",
   "name": "ALBI Grade (Albumin-Bilirubin)",
   "short": "ALBI",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/albi/",
   "summary": "The ALBI score = 0.66 × log₁₀(bilirubin µmol/L) − 0.085 × albumin (g/L) grades liver function, particularly in hepatocellular carcinoma. Grade 1 ≤ −2.60, grade 2 > −2.60 to ≤ −1.39, grade 3 > −1.39.",
   "formula": "ALBI = 0.66 × log₁₀[bilirubin (µmol/L)] − 0.085 × albumin (g/L)",
   "inputs": [
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 7
    }
   ],
   "references": [
    {
     "title": "Johnson PJ et al. Assessment of liver function in patients with hepatocellular carcinoma: a new evidence-based approach—the ALBI grade. J Clin Oncol 2015;33:550–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/25512453/"
    }
   ]
  },
  {
   "id": "albumin-corrected-delta-gap",
   "name": "Albumin-Corrected Delta Gap",
   "short": "Alb-corrected Δgap",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/albumin-corrected-delta-gap/",
   "summary": "Albumin-corrected delta gap = albumin-corrected anion gap − 12, where corrected AG = Na − (Cl + HCO₃) + 2.5 × (4 − albumin g/dL). Compare it with the bicarbonate fall (24 − HCO₃): a delta gap clearly larger than the HCO₃ fall suggests a concurrent metabolic alkalosis; clearly smaller suggests an added normal-gap acidosis.",
   "formula": "Corrected AG = Na⁺ − (Cl⁻ + HCO₃⁻) + 2.5 × (4 − albumin g/dL). Albumin-corrected delta gap = corrected AG − 12. Mixed-disorder check: corrected HCO₃ = HCO₃ + Δgap (>26 alkalosis, <22 added normal-gap acidosis).",
   "inputs": [
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "cl",
     "label": "Serum chloride",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 60,
     "max": 150
    },
    {
     "id": "hco3",
     "label": "Serum bicarbonate (HCO₃⁻)",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 60
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 6.5
    }
   ],
   "references": [
    {
     "title": "Figge J et al. Anion gap and hypoalbuminemia. Crit Care Med 1998;26:1807–10.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9824071/"
    },
    {
     "title": "Rastegar A. Use of the ΔAG/ΔHCO3− ratio in the diagnosis of mixed acid-base disorders. J Am Soc Nephrol 2007;18:2429–31.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/17656477/"
    },
    {
     "title": "MedCalc-Bench reference implementation (albumin_corrected_delta_gap.py).",
     "url": "https://github.com/ncbi-nlp/MedCalc-Bench/tree/main/calculator_implementations"
    }
   ]
  },
  {
   "id": "albumin-corrected-delta-ratio",
   "name": "Albumin-Corrected Delta Ratio",
   "short": "Alb-corrected Δratio",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/albumin-corrected-delta-ratio/",
   "summary": "Albumin-corrected delta ratio = (albumin-corrected AG − 12) ÷ (24 − HCO₃), with corrected AG = Na − (Cl + HCO₃) + 2.5 × (4 − albumin g/dL). <0.4 normal-gap acidosis, 0.4–0.8 mixed high- and normal-gap acidosis, 0.8–2 pure high-gap acidosis, >2 concurrent metabolic alkalosis or chronic respiratory acidosis.",
   "formula": "Delta ratio = [Na⁺ − (Cl⁻ + HCO₃⁻) + 2.5 × (4 − albumin g/dL) − 12] ÷ (24 − HCO₃⁻)",
   "inputs": [
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "cl",
     "label": "Serum chloride",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 60,
     "max": 150
    },
    {
     "id": "hco3",
     "label": "Serum bicarbonate (HCO₃⁻)",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 60
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 6.5
    }
   ],
   "references": [
    {
     "title": "Rastegar A. Use of the ΔAG/ΔHCO3− ratio in the diagnosis of mixed acid-base disorders. J Am Soc Nephrol 2007;18:2429–31.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/17656477/"
    },
    {
     "title": "Figge J et al. Anion gap and hypoalbuminemia. Crit Care Med 1998;26:1807–10.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9824071/"
    },
    {
     "title": "MedCalc-Bench reference implementation (albumin_delta_ratio.py).",
     "url": "https://github.com/ncbi-nlp/MedCalc-Bench/tree/main/calculator_implementations"
    }
   ]
  },
  {
   "id": "alvarado",
   "name": "Alvarado Score for Acute Appendicitis",
   "short": "Alvarado",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/alvarado/",
   "summary": "The Alvarado (MANTRELS) score estimates the probability of acute appendicitis from 8 findings (0–10 points). Scores 1–4 make appendicitis unlikely, 5–6 are equivocal, 7–8 probable and 9–10 very probable.",
   "formula": "Migration of pain 1 · Anorexia 1 · Nausea/vomiting 1 · RLQ tenderness 2 · Rebound 1 · Temperature ≥37.3 °C 1 · Leukocytosis >10 ×10⁹/L 2 · Neutrophils >75% (left shift) 1",
   "inputs": [
    {
     "id": "migration",
     "label": "Migration of pain to the right lower quadrant",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "anorexia",
     "label": "Anorexia (or acetone in urine)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "nv",
     "label": "Nausea or vomiting",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "rlq",
     "label": "Right lower quadrant tenderness",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "rebound",
     "label": "Rebound tenderness",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "temp",
     "label": "Temperature",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 30,
     "max": 45
    },
    {
     "id": "wbc",
     "label": "White blood cell count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0.1,
     "max": 300
    },
    {
     "id": "neut",
     "label": "Neutrophils (% of WBC)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Alvarado A. A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med 1986;15:557–64.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3963537/"
    }
   ]
  },
  {
   "id": "a-a-gradient",
   "name": "Alveolar–Arterial (A–a) O2 Gradient",
   "short": "A–a gradient",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/a-a-gradient/",
   "summary": "A–a gradient = PAO₂ − PaO₂, where PAO₂ = FiO₂ × (Patm − 47) − PaCO₂/0.8. On room air the normal gradient rises with age, roughly age/4 + 4 mmHg; a raised gradient points to V/Q mismatch, shunt or diffusion impairment rather than hypoventilation.",
   "formula": "PAO₂ = FiO₂ × (Patm − 47) − PaCO₂ ÷ 0.8;  A–a gradient = PAO₂ − PaO₂;  expected upper limit ≈ age/4 + 4 mmHg (room air). Patm 760 mmHg at sea level; 47 = water vapour pressure.",
   "inputs": [
    {
     "id": "fio2",
     "label": "FiO₂",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 21,
     "max": 100
    },
    {
     "id": "pao2",
     "label": "Arterial PaO₂",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 20,
     "max": 700
    },
    {
     "id": "pco2",
     "label": "Arterial PaCO₂",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 5,
     "max": 150
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "patm",
     "label": "Barometric pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 400,
     "max": 800,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Mellemgaard K. The alveolar-arterial oxygen difference: its size and components in normal man. Acta Physiol Scand 1966;67:10–20.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/5963295/"
    }
   ]
  },
  {
   "id": "apache-ii",
   "name": "APACHE II Score",
   "short": "APACHE II",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/apache-ii/",
   "summary": "APACHE II grades ICU illness severity (0–71) from the worst values in the first 24 hours of 12 physiologic variables, plus age and chronic health points. Higher scores mean higher hospital mortality; scores ≥25 indicate very severe illness.",
   "formula": "APACHE II = Acute Physiology Score (12 variables, worst value in first 24 h: temperature, MAP, HR, RR, oxygenation [A–a gradient if FiO₂ ≥0.5, else PaO₂], arterial pH, Na, K, creatinine [double points in acute renal failure], hematocrit, WBC, 15 − GCS) + age points (≤44 0, 45–54 2, 55–64 3, 65–74 5, ≥75 6) + chronic health points (5 non-operative/emergency post-op, 2 elective post-op). A–a = FiO₂ × 713 − PaCO₂/0.8 − PaO₂.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "temp",
     "label": "Temperature (rectal/core)",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 20,
     "max": 45
    },
    {
     "id": "map",
     "label": "Mean arterial pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 250
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 80
    },
    {
     "id": "fio2",
     "label": "FiO₂ (% or fraction)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0.21,
     "max": 100
    },
    {
     "id": "pao2",
     "label": "PaO₂ (arterial)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 700
    },
    {
     "id": "paco2",
     "label": "PaCO₂ (needed if FiO₂ ≥50%)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 5,
     "max": 200,
     "optional": true
    },
    {
     "id": "ph",
     "label": "Arterial pH",
     "kind": "num",
     "min": 6.5,
     "max": 8
    },
    {
     "id": "na",
     "label": "Sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "k",
     "label": "Potassium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 10
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "arf",
     "label": "Acute renal failure",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "hct",
     "label": "Hematocrit",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 5,
     "max": 80
    },
    {
     "id": "wbc",
     "label": "WBC",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 500
    },
    {
     "id": "gcs",
     "label": "Glasgow Coma Scale",
     "kind": "num",
     "min": 3,
     "max": 15
    },
    {
     "id": "chronic",
     "label": "Chronic health (severe organ insufficiency or immunocompromise)",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "nonop",
       "label": "Yes: non-operative or emergency post-op",
       "points": 5
      },
      {
       "value": "elective",
       "label": "Yes: elective post-op",
       "points": 2
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Knaus WA et al. APACHE II: a severity of disease classification system. Crit Care Med 1985;13:818–29.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3928249/"
    }
   ]
  },
  {
   "id": "apfel",
   "name": "Apfel Score for Postoperative Nausea and Vomiting (PONV)",
   "short": "Apfel",
   "category": "Surgery & Perioperative",
   "url": "https://askcalc.site/calc/apfel/",
   "summary": "The simplified Apfel score counts four PONV risk factors (female sex, non-smoker, history of PONV or motion sickness, postoperative opioids). 0, 1, 2, 3 and 4 factors predict PONV risks of about 10%, 21%, 39%, 61% and 79%; prophylaxis is advised with ≥2 factors.",
   "formula": "One point each: female sex, non-smoker, history of PONV or motion sickness, planned postoperative opioids. Risk of PONV in 24 h: 0 = 10%, 1 = 21%, 2 = 39%, 3 = 61%, 4 = 79%.",
   "inputs": [
    {
     "id": "female",
     "label": "Female sex",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "nonsmoker",
     "label": "Non-smoker",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "history",
     "label": "History of PONV or motion sickness",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "opioids",
     "label": "Postoperative opioids planned",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Apfel CC et al. A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers. Anesthesiology 1999;91:693–700.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10485781/"
    }
   ]
  },
  {
   "id": "apgar",
   "name": "APGAR Score (Newborn Assessment)",
   "short": "APGAR",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/apgar/",
   "summary": "The APGAR score rates a newborn at 1 and 5 minutes on appearance, pulse, grimace, activity and respiration (0–2 each, total 0–10). A score of 7–10 is reassuring, 4–6 moderately abnormal and 0–3 low.",
   "formula": "Sum of Appearance + Pulse + Grimace + Activity + Respiration, each 0–2 (total 0–10). Score at 1 and 5 min; if 5-min score < 7, repeat every 5 min up to 20 min.",
   "inputs": [
    {
     "id": "appearance",
     "label": "Appearance (skin colour)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Blue or pale all over",
       "points": 0
      },
      {
       "value": "1",
       "label": "Body pink, extremities blue (acrocyanosis)",
       "points": 1
      },
      {
       "value": "2",
       "label": "Completely pink",
       "points": 2
      }
     ]
    },
    {
     "id": "pulse",
     "label": "Pulse (heart rate)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Absent",
       "points": 0
      },
      {
       "value": "1",
       "label": "< 100 /min",
       "points": 1
      },
      {
       "value": "2",
       "label": "≥ 100 /min",
       "points": 2
      }
     ]
    },
    {
     "id": "grimace",
     "label": "Grimace (reflex irritability)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No response to stimulation",
       "points": 0
      },
      {
       "value": "1",
       "label": "Grimace on stimulation",
       "points": 1
      },
      {
       "value": "2",
       "label": "Cry or active withdrawal",
       "points": 2
      }
     ]
    },
    {
     "id": "activity",
     "label": "Activity (muscle tone)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Limp",
       "points": 0
      },
      {
       "value": "1",
       "label": "Some flexion",
       "points": 1
      },
      {
       "value": "2",
       "label": "Active motion",
       "points": 2
      }
     ]
    },
    {
     "id": "respiration",
     "label": "Respiration",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Absent",
       "points": 0
      },
      {
       "value": "1",
       "label": "Weak, irregular or gasping",
       "points": 1
      },
      {
       "value": "2",
       "label": "Good, crying",
       "points": 2
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Apgar V. A proposal for a new method of evaluation of the newborn infant. Curr Res Anesth Analg 1953;32:260–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/13083014/"
    },
    {
     "title": "AAP Committee on Fetus and Newborn; ACOG Committee on Obstetric Practice. The Apgar Score. Pediatrics 2015;136:819–22.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/26416932/"
    }
   ]
  },
  {
   "id": "apri",
   "name": "APRI (AST to Platelet Ratio Index)",
   "short": "APRI",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/apri/",
   "summary": "APRI = (AST ÷ AST upper limit of normal) ÷ platelets (10⁹/L) × 100. In hepatitis C, APRI ≤0.5 makes significant fibrosis unlikely, >1.5 makes it likely, and >2.0 suggests cirrhosis (WHO); ≤1.0 largely excludes cirrhosis.",
   "formula": "APRI = [AST (U/L) ÷ AST ULN (U/L)] ÷ platelets (10⁹/L) × 100",
   "inputs": [
    {
     "id": "ast",
     "label": "AST",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 1,
     "max": 20000
    },
    {
     "id": "plt",
     "label": "Platelet count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 1,
     "max": 2000
    },
    {
     "id": "astUln",
     "label": "AST upper limit of normal",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 10,
     "max": 100,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Wai CT et al. A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C. Hepatology 2003;38:518–26.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12883497/"
    }
   ]
  },
  {
   "id": "ardsnet-tidal-volume",
   "name": "ARDSNet Tidal Volume (Predicted Body Weight)",
   "short": "Lung-protective VT",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/ardsnet-tidal-volume/",
   "summary": "Lung-protective ventilation targets a tidal volume of 6 mL/kg predicted body weight (range 4–8 mL/kg), with plateau pressure ≤30 cmH₂O. PBW (kg) = 50 + 0.91 × (height cm − 152.4) for men and 45.5 + 0.91 × (height cm − 152.4) for women.",
   "formula": "PBW (men) = 50 + 0.91 × (height cm − 152.4); PBW (women) = 45.5 + 0.91 × (height cm − 152.4); VT = 6 mL/kg × PBW (range 4–8)",
   "inputs": [
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 100,
     "max": 250
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Acute Respiratory Distress Syndrome Network. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and ARDS. N Engl J Med 2000;342:1301–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10793162/"
    }
   ]
  },
  {
   "id": "ascvd-pce",
   "name": "ASCVD 10-Year Risk (2013 Pooled Cohort Equations)",
   "short": "ASCVD (PCE)",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/ascvd-pce/",
   "summary": "The 2013 ACC/AHA Pooled Cohort Equations estimate 10-year risk of a first hard ASCVD event (CHD death, nonfatal MI, fatal or nonfatal stroke) for adults 40–79 without ASCVD. Risk <5% low, 5–7.4% borderline, 7.5–19.9% intermediate, ≥20% high (2018/2019 statin guidance).",
   "formula": "10-yr risk = 1 − S₁₀^exp(Σβx − mean), sex- and race-specific coefficients on ln(age), ln(TC), ln(HDL), ln(SBP, treated or untreated), smoking, diabetes and interactions (Goff 2013). Baseline S₁₀ / mean: white women 0.9665 / −29.18; African American women 0.9533 / 86.61; white men 0.9144 / 61.18; African American men 0.8954 / 19.54.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 40,
     "max": 79
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "race",
     "label": "Race (equation set)",
     "kind": "sel",
     "options": [
      {
       "value": "white",
       "label": "White or other"
      },
      {
       "value": "aa",
       "label": "African American"
      }
     ]
    },
    {
     "id": "tc",
     "label": "Total cholesterol",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 130,
     "max": 320
    },
    {
     "id": "hdl",
     "label": "HDL cholesterol",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 20,
     "max": 100
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "bp_tx",
     "label": "On blood-pressure treatment",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "smoker",
     "label": "Current smoker",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "dm",
     "label": "Diabetes mellitus",
     "kind": "yn",
     "points": 0
    }
   ],
   "references": [
    {
     "title": "Goff DC Jr et al. 2013 ACC/AHA guideline on the assessment of cardiovascular risk. Circulation 2014;129(25 Suppl 2):S49–73.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/24222018/"
    },
    {
     "title": "Grundy SM et al. 2018 AHA/ACC/Multisociety Guideline on the Management of Blood Cholesterol. Circulation 2019;139:e1082–e1143.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/30586774/"
    }
   ]
  },
  {
   "id": "atria-bleeding",
   "name": "ATRIA Bleeding Risk Score",
   "short": "ATRIA bleeding",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/atria-bleeding/",
   "summary": "ATRIA predicts major hemorrhage on warfarin in atrial fibrillation (0–10 points): anemia 3, severe renal disease 3, age ≥75 2, prior hemorrhage 1, hypertension 1. Low risk 0–3 (0.8%/yr), intermediate 4 (2.6%/yr), high 5–10 (5.8%/yr).",
   "formula": "Anemia 3 · severe renal disease (eGFR <30 or dialysis) 3 · age ≥75 2 · any prior hemorrhage 1 · hypertension 1 (max 10)",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "anemia",
     "label": "Anemia (Hb <13 g/dL men, <12 g/dL women)",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "renal",
     "label": "Severe renal disease (eGFR <30 mL/min or dialysis)",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "prior_bleed",
     "label": "Any prior hemorrhage diagnosis",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "htn",
     "label": "Diagnosed hypertension",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Fang MC et al. A new risk scheme to predict warfarin-associated hemorrhage: the ATRIA Study. J Am Coll Cardiol 2011;58:395–401.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/21757117/"
    }
   ]
  },
  {
   "id": "audit",
   "name": "AUDIT Alcohol Use Disorders Identification Test",
   "short": "AUDIT",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/audit/",
   "summary": "The WHO AUDIT is a 10-item alcohol screen scored 0–40. Scores of 8 or more indicate hazardous or harmful drinking; WHO risk zones are 0–7 (low risk), 8–15 (simple advice), 16–19 (brief counselling and monitoring) and 20–40 (referral for diagnostic evaluation and treatment).",
   "formula": "Q1–8 scored 0–4; Q9–10 scored 0, 2 or 4. Total 0–40. Positive screen ≥8.",
   "inputs": [
    {
     "id": "q1",
     "label": "How often do you have a drink containing alcohol?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Never",
       "points": 0
      },
      {
       "value": "1",
       "label": "Monthly or less",
       "points": 1
      },
      {
       "value": "2",
       "label": "2–4 times a month",
       "points": 2
      },
      {
       "value": "3",
       "label": "2–3 times a week",
       "points": 3
      },
      {
       "value": "4",
       "label": "4 or more times a week",
       "points": 4
      }
     ]
    },
    {
     "id": "q2",
     "label": "How many standard drinks containing alcohol do you have on a typical day when you are drinking?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "1 or 2",
       "points": 0
      },
      {
       "value": "1",
       "label": "3 or 4",
       "points": 1
      },
      {
       "value": "2",
       "label": "5 or 6",
       "points": 2
      },
      {
       "value": "3",
       "label": "7 to 9",
       "points": 3
      },
      {
       "value": "4",
       "label": "10 or more",
       "points": 4
      }
     ]
    },
    {
     "id": "q3",
     "label": "How often do you have six or more drinks on one occasion?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Never",
       "points": 0
      },
      {
       "value": "1",
       "label": "Less than monthly",
       "points": 1
      },
      {
       "value": "2",
       "label": "Monthly",
       "points": 2
      },
      {
       "value": "3",
       "label": "Weekly",
       "points": 3
      },
      {
       "value": "4",
       "label": "Daily or almost daily",
       "points": 4
      }
     ]
    },
    {
     "id": "q4",
     "label": "How often during the last year have you found that you were not able to stop drinking once you had started?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Never",
       "points": 0
      },
      {
       "value": "1",
       "label": "Less than monthly",
       "points": 1
      },
      {
       "value": "2",
       "label": "Monthly",
       "points": 2
      },
      {
       "value": "3",
       "label": "Weekly",
       "points": 3
      },
      {
       "value": "4",
       "label": "Daily or almost daily",
       "points": 4
      }
     ]
    },
    {
     "id": "q5",
     "label": "How often during the last year have you failed to do what was normally expected of you because of drinking?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Never",
       "points": 0
      },
      {
       "value": "1",
       "label": "Less than monthly",
       "points": 1
      },
      {
       "value": "2",
       "label": "Monthly",
       "points": 2
      },
      {
       "value": "3",
       "label": "Weekly",
       "points": 3
      },
      {
       "value": "4",
       "label": "Daily or almost daily",
       "points": 4
      }
     ]
    },
    {
     "id": "q6",
     "label": "How often during the last year have you needed a first drink in the morning to get yourself going after a heavy drinking session?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Never",
       "points": 0
      },
      {
       "value": "1",
       "label": "Less than monthly",
       "points": 1
      },
      {
       "value": "2",
       "label": "Monthly",
       "points": 2
      },
      {
       "value": "3",
       "label": "Weekly",
       "points": 3
      },
      {
       "value": "4",
       "label": "Daily or almost daily",
       "points": 4
      }
     ]
    },
    {
     "id": "q7",
     "label": "How often during the last year have you had a feeling of guilt or remorse after drinking?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Never",
       "points": 0
      },
      {
       "value": "1",
       "label": "Less than monthly",
       "points": 1
      },
      {
       "value": "2",
       "label": "Monthly",
       "points": 2
      },
      {
       "value": "3",
       "label": "Weekly",
       "points": 3
      },
      {
       "value": "4",
       "label": "Daily or almost daily",
       "points": 4
      }
     ]
    },
    {
     "id": "q8",
     "label": "How often during the last year have you been unable to remember what happened the night before because of drinking?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Never",
       "points": 0
      },
      {
       "value": "1",
       "label": "Less than monthly",
       "points": 1
      },
      {
       "value": "2",
       "label": "Monthly",
       "points": 2
      },
      {
       "value": "3",
       "label": "Weekly",
       "points": 3
      },
      {
       "value": "4",
       "label": "Daily or almost daily",
       "points": 4
      }
     ]
    },
    {
     "id": "q9",
     "label": "Have you or someone else been injured as a result of your drinking?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No",
       "points": 0
      },
      {
       "value": "2",
       "label": "Yes, but not in the last year",
       "points": 2
      },
      {
       "value": "4",
       "label": "Yes, during the last year",
       "points": 4
      }
     ]
    },
    {
     "id": "q10",
     "label": "Has a relative, friend, doctor or other health worker been concerned about your drinking or suggested you cut down?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No",
       "points": 0
      },
      {
       "value": "2",
       "label": "Yes, but not in the last year",
       "points": 2
      },
      {
       "value": "4",
       "label": "Yes, during the last year",
       "points": 4
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Saunders JB et al. Development of the Alcohol Use Disorders Identification Test (AUDIT). Addiction 1993;88:791–804.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8329970/"
    },
    {
     "title": "Babor TF et al. AUDIT: Guidelines for Use in Primary Care, 2nd ed. WHO 2001.",
     "url": "https://www.who.int/publications/i/item/WHO-MSD-MSB-01.6a"
    }
   ]
  },
  {
   "id": "audit-c",
   "name": "AUDIT-C Alcohol Use Screen",
   "short": "AUDIT-C",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/audit-c/",
   "summary": "The AUDIT-C uses the first three AUDIT consumption questions (0–12 points) to screen for alcohol misuse. A score ≥4 in men or ≥3 in women is a positive screen; higher scores mean greater risk.",
   "formula": "Q1 frequency (0–4) + Q2 drinks on a typical drinking day (0–4) + Q3 frequency of ≥6 drinks on one occasion (0–4). Range 0–12. Positive: ≥4 men, ≥3 women.",
   "inputs": [
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "q1",
     "label": "How often do you have a drink containing alcohol?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Never",
       "points": 0
      },
      {
       "value": "1",
       "label": "Monthly or less",
       "points": 1
      },
      {
       "value": "2",
       "label": "2–4 times a month",
       "points": 2
      },
      {
       "value": "3",
       "label": "2–3 times a week",
       "points": 3
      },
      {
       "value": "4",
       "label": "4 or more times a week",
       "points": 4
      }
     ]
    },
    {
     "id": "q2",
     "label": "How many standard drinks containing alcohol do you have on a typical day when you are drinking?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "1 or 2",
       "points": 0
      },
      {
       "value": "1",
       "label": "3 or 4",
       "points": 1
      },
      {
       "value": "2",
       "label": "5 or 6",
       "points": 2
      },
      {
       "value": "3",
       "label": "7 to 9",
       "points": 3
      },
      {
       "value": "4",
       "label": "10 or more",
       "points": 4
      }
     ]
    },
    {
     "id": "q3",
     "label": "How often do you have six or more drinks on one occasion?",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Never",
       "points": 0
      },
      {
       "value": "1",
       "label": "Less than monthly",
       "points": 1
      },
      {
       "value": "2",
       "label": "Monthly",
       "points": 2
      },
      {
       "value": "3",
       "label": "Weekly",
       "points": 3
      },
      {
       "value": "4",
       "label": "Daily or almost daily",
       "points": 4
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Bush K et al. The AUDIT alcohol consumption questions (AUDIT-C): an effective brief screening test for problem drinking. Arch Intern Med 1998;158:1789–95.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9738608/"
    },
    {
     "title": "Bradley KA et al. AUDIT-C as a brief screen for alcohol misuse in primary care. Alcohol Clin Exp Res 2007;31:1208–17.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/17451397/"
    }
   ]
  },
  {
   "id": "schwartz-bedside",
   "name": "Bedside Schwartz eGFR (Pediatric)",
   "short": "Bedside Schwartz",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/schwartz-bedside/",
   "summary": "The 2009 bedside Schwartz equation estimates GFR in children as 0.413 × height (cm) ÷ serum creatinine (mg/dL), in mL/min/1.73 m². Developed in children aged 1–16 with CKD; values <90 suggest reduced function.",
   "formula": "eGFR (mL/min/1.73 m²) = 0.413 × height (cm) ÷ Scr (mg/dL). SI: 36.5 × height (cm) ÷ Scr (µmol/L).",
   "inputs": [
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 45,
     "max": 200
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 15
    }
   ],
   "references": [
    {
     "title": "Schwartz GJ et al. New equations to estimate GFR in children with CKD. J Am Soc Nephrol 2009;20:629–37.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/19158356/"
    }
   ]
  },
  {
   "id": "bicarbonate-deficit",
   "name": "Bicarbonate Deficit",
   "short": "HCO3 deficit",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/bicarbonate-deficit/",
   "summary": "Bicarbonate deficit = 0.5 × weight (kg) × (target − measured HCO₃) mmol. Give about half over several hours and recheck; the apparent bicarbonate space rises as HCO₃ falls (0.4 + 2.6/HCO₃).",
   "formula": "HCO₃ deficit (mmol) = 0.5 × weight (kg) × (target HCO₃ − measured HCO₃). Variable space: (0.4 + 2.6 ÷ HCO₃) × weight × (target − measured).",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "hco3",
     "label": "Serum bicarbonate (HCO₃⁻)",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 40
    },
    {
     "id": "target",
     "label": "Target HCO₃⁻",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 5,
     "max": 30,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Fernandez PC, Cohen RM, Feldman GM. The concept of bicarbonate distribution space: the crucial role of body buffers. Kidney Int 1989;36:747–52.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/2693799/"
    }
   ]
  },
  {
   "id": "bisap",
   "name": "BISAP Score for Acute Pancreatitis Mortality",
   "short": "BISAP",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/bisap/",
   "summary": "BISAP (0–5) predicts in-hospital mortality in acute pancreatitis within the first 24 hours: one point each for BUN >25 mg/dL, impaired mental status, SIRS, age >60 and pleural effusion. A score ≥3 marks substantially increased mortality.",
   "formula": "One point each within 24 h: BUN >25 mg/dL (urea >8.9 mmol/L) · Impaired mental status · SIRS · Age >60 · Pleural effusion",
   "inputs": [
    {
     "id": "bun",
     "label": "BUN / urea",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "ams",
     "label": "Impaired mental status (GCS <15, disorientation)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "sirs",
     "label": "SIRS (≥2 of: T <36 or >38 °C, HR >90, RR >20 or PaCO₂ <32, WBC <4 or >12)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 12,
     "max": 120
    },
    {
     "id": "effusion",
     "label": "Pleural effusion on imaging",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Wu BU et al. The early prediction of mortality in acute pancreatitis: a large population-based study. Gut 2008;57:1698–703.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18519429/"
    }
   ]
  },
  {
   "id": "bishop",
   "name": "Bishop Score (Cervical Ripeness for Induction)",
   "short": "Bishop score",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/bishop/",
   "summary": "The Bishop score (0–13) rates cervical dilation, effacement, consistency, position and fetal station to predict successful induction of labour. A score >8 means vaginal delivery after induction is about as likely as with spontaneous labour; ≤6 is unfavourable and usually warrants cervical ripening.",
   "formula": "Dilation: closed 0, 1–2 cm 1, 3–4 cm 2, ≥5 cm 3 · Effacement: 0–30% 0, 40–50% 1, 60–70% 2, ≥80% 3 · Station: −3 0, −2 1, −1/0 2, +1/+2 3 · Consistency: firm 0, medium 1, soft 2 · Position: posterior 0, mid 1, anterior 2",
   "inputs": [
    {
     "id": "dilation",
     "label": "Dilation",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Closed (0 cm)",
       "points": 0
      },
      {
       "value": "1-2",
       "label": "1–2 cm",
       "points": 1
      },
      {
       "value": "3-4",
       "label": "3–4 cm",
       "points": 2
      },
      {
       "value": "5+",
       "label": "≥ 5 cm",
       "points": 3
      }
     ]
    },
    {
     "id": "effacement",
     "label": "Effacement",
     "kind": "sel",
     "options": [
      {
       "value": "0-30",
       "label": "0–30%",
       "points": 0
      },
      {
       "value": "40-50",
       "label": "40–50%",
       "points": 1
      },
      {
       "value": "60-70",
       "label": "60–70%",
       "points": 2
      },
      {
       "value": "80+",
       "label": "≥ 80%",
       "points": 3
      }
     ]
    },
    {
     "id": "station",
     "label": "Fetal station",
     "kind": "sel",
     "options": [
      {
       "value": "-3",
       "label": "−3",
       "points": 0
      },
      {
       "value": "-2",
       "label": "−2",
       "points": 1
      },
      {
       "value": "-1/0",
       "label": "−1 or 0",
       "points": 2
      },
      {
       "value": "+1/+2",
       "label": "+1 or +2",
       "points": 3
      }
     ]
    },
    {
     "id": "consistency",
     "label": "Cervical consistency",
     "kind": "sel",
     "options": [
      {
       "value": "firm",
       "label": "Firm",
       "points": 0
      },
      {
       "value": "medium",
       "label": "Medium",
       "points": 1
      },
      {
       "value": "soft",
       "label": "Soft",
       "points": 2
      }
     ]
    },
    {
     "id": "position",
     "label": "Cervical position",
     "kind": "sel",
     "options": [
      {
       "value": "posterior",
       "label": "Posterior",
       "points": 0
      },
      {
       "value": "mid",
       "label": "Mid-position",
       "points": 1
      },
      {
       "value": "anterior",
       "label": "Anterior",
       "points": 2
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Bishop EH. Pelvic scoring for elective induction. Obstet Gynecol 1964;24:266–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/14199536/"
    }
   ]
  },
  {
   "id": "bode",
   "name": "BODE Index for COPD Survival",
   "short": "BODE",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/bode/",
   "summary": "The BODE index (0–10) predicts mortality in COPD from Body-mass index, airflow Obstruction (FEV₁ % predicted), Dyspnea (mMRC) and Exercise capacity (6-minute walk distance). Higher quartiles (0–2, 3–4, 5–6, 7–10) carry approximate 4-year survival of 80%, 67%, 57% and 18%.",
   "formula": "FEV₁ %pred: ≥65 0, 50–64 1, 36–49 2, ≤35 3 · 6MWD (m): ≥350 0, 250–349 1, 150–249 2, ≤149 3 · mMRC: 0–1 0, 2 1, 3 2, 4 3 · BMI: >21 0, ≤21 1",
   "inputs": [
    {
     "id": "fev1",
     "label": "FEV₁ (% predicted, post-bronchodilator)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 5,
     "max": 150
    },
    {
     "id": "walk",
     "label": "6-minute walk distance (m)",
     "kind": "num",
     "min": 0,
     "max": 1000
    },
    {
     "id": "mmrc",
     "label": "mMRC dyspnea grade",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: breathless only with strenuous exercise",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: short of breath hurrying on level or walking up a slight hill",
       "points": 0
      },
      {
       "value": "2",
       "label": "2: walks slower than peers or stops for breath at own pace",
       "points": 1
      },
      {
       "value": "3",
       "label": "3: stops for breath after ~100 m or a few minutes on level",
       "points": 2
      },
      {
       "value": "4",
       "label": "4: too breathless to leave the house or when dressing",
       "points": 3
      }
     ]
    },
    {
     "id": "bmi",
     "label": "BMI",
     "kind": "num",
     "min": 8,
     "max": 80
    }
   ],
   "references": [
    {
     "title": "Celli BR et al. The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease. N Engl J Med 2004;350:1005–12.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/14999112/"
    }
   ]
  },
  {
   "id": "bmi",
   "name": "Body Mass Index (BMI)",
   "short": "BMI",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/bmi/",
   "summary": "BMI is weight in kilograms divided by height in metres squared. It classifies adults as underweight (<18.5), normal (18.5–24.9), overweight (25–29.9) or obese (≥30, classes I–III).",
   "formula": "BMI = weight (kg) ÷ height (m)²",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 0.3,
     "max": 400
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 30,
     "max": 250
    }
   ],
   "references": [
    {
     "title": "WHO. Obesity: preventing and managing the global epidemic. Technical Report Series 894 (2000).",
     "url": "https://iris.who.int/handle/10665/42330"
    }
   ]
  },
  {
   "id": "bsa",
   "name": "Body Surface Area (Mosteller)",
   "short": "BSA",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/bsa/",
   "summary": "Body surface area by the Mosteller formula, √(height cm × weight kg ÷ 3600), used for chemotherapy dosing and indexing cardiac output. Average adult BSA is about 1.7–1.9 m².",
   "formula": "BSA (m²) = √(height (cm) × weight (kg) ÷ 3600)   ·   Du Bois: 0.007184 × W^0.425 × H^0.725",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 0.3,
     "max": 400
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 30,
     "max": 250
    }
   ],
   "references": [
    {
     "title": "Mosteller RD. Simplified calculation of body-surface area. N Engl J Med 1987;317:1098.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3657876/"
    }
   ]
  },
  {
   "id": "boston-bowel-prep",
   "name": "Boston Bowel Preparation Scale (BBPS)",
   "short": "BBPS",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/boston-bowel-prep/",
   "summary": "The Boston Bowel Preparation Scale scores right, transverse and left colon cleanliness 0–3 each after washing and suctioning (total 0–9). Preparation is adequate for standard surveillance intervals when every segment scores ≥2 (total ≥6); a total ≤2 warrants repeat colonoscopy within a year.",
   "formula": "Each segment (right incl. cecum/ascending; transverse incl. flexures; left incl. descending/sigmoid/rectum): 0 = unprepared, solid stool cannot be cleared; 1 = portion of mucosa seen, other areas obscured; 2 = minor residual staining/small fragments, mucosa well seen; 3 = entire mucosa well seen. Total = sum (0–9).",
   "inputs": [
    {
     "id": "right",
     "label": "Right colon segment",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Unprepared, solid stool that cannot be cleared"
      },
      {
       "value": "1",
       "label": "1: Portion of mucosa seen; other areas obscured"
      },
      {
       "value": "2",
       "label": "2: Minor residual staining or small fragments; mucosa well seen"
      },
      {
       "value": "3",
       "label": "3: Entire mucosa well seen"
      }
     ]
    },
    {
     "id": "transverse",
     "label": "Transverse colon segment",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Unprepared, solid stool that cannot be cleared"
      },
      {
       "value": "1",
       "label": "1: Portion of mucosa seen; other areas obscured"
      },
      {
       "value": "2",
       "label": "2: Minor residual staining or small fragments; mucosa well seen"
      },
      {
       "value": "3",
       "label": "3: Entire mucosa well seen"
      }
     ]
    },
    {
     "id": "left",
     "label": "Left colon segment",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Unprepared, solid stool that cannot be cleared"
      },
      {
       "value": "1",
       "label": "1: Portion of mucosa seen; other areas obscured"
      },
      {
       "value": "2",
       "label": "2: Minor residual staining or small fragments; mucosa well seen"
      },
      {
       "value": "3",
       "label": "3: Entire mucosa well seen"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Lai EJ et al. The Boston bowel preparation scale: a valid and reliable instrument for colonoscopy-oriented research. Gastrointest Endosc 2009;69:620–5.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/19136102/"
    },
    {
     "title": "Calderwood AH et al. Boston Bowel Preparation Scale scores provide a standardized definition of adequate for describing bowel cleanliness. Gastrointest Endosc 2014;80:269–76.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/24629422/"
    }
   ]
  },
  {
   "id": "pews-brighton",
   "name": "Brighton Paediatric Early Warning Score (PEWS)",
   "short": "Brighton PEWS",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/pews-brighton/",
   "summary": "The Brighton PEWS (0–13) scores behaviour, cardiovascular and respiratory status (0–3 each), plus 2 for quarter-hourly nebulisers and 2 for persistent post-operative vomiting. Higher scores mean deterioration; a score ≥4 or 3 in any single domain commonly triggers medical review (thresholds are set locally).",
   "formula": "Behaviour 0–3 + Cardiovascular 0–3 + Respiratory 0–3 + 2 (nebulisers every 15 min) + 2 (persistent post-operative vomiting); maximum 13",
   "inputs": [
    {
     "id": "behaviour",
     "label": "Behaviour",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Playing / appropriate",
       "points": 0
      },
      {
       "value": "1",
       "label": "Sleeping",
       "points": 1
      },
      {
       "value": "2",
       "label": "Irritable",
       "points": 2
      },
      {
       "value": "3",
       "label": "Lethargic / confused, or reduced response to pain",
       "points": 3
      }
     ]
    },
    {
     "id": "cardio",
     "label": "Cardiovascular",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Pink, or capillary refill 1–2 s",
       "points": 0
      },
      {
       "value": "1",
       "label": "Pale, or capillary refill 3 s",
       "points": 1
      },
      {
       "value": "2",
       "label": "Grey, or capillary refill 4 s, or HR 20 above normal for age",
       "points": 2
      },
      {
       "value": "3",
       "label": "Grey and mottled, or capillary refill ≥ 5 s, or HR 30 above normal, or bradycardia",
       "points": 3
      }
     ]
    },
    {
     "id": "resp",
     "label": "Respiratory",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Within normal parameters, no recession or tracheal tug",
       "points": 0
      },
      {
       "value": "1",
       "label": "RR > 10 above normal, accessory muscles, or ≥ 30% FiO₂ / ≥ 3 L/min",
       "points": 1
      },
      {
       "value": "2",
       "label": "RR > 20 above normal, recession, tracheal tug, or ≥ 40% FiO₂ / ≥ 6 L/min",
       "points": 2
      },
      {
       "value": "3",
       "label": "RR 5 below normal with sternal recession, tug or grunting, or ≥ 50% FiO₂ / ≥ 8 L/min",
       "points": 3
      }
     ]
    },
    {
     "id": "nebs",
     "label": "Quarter-hourly (every 15 min) nebulisers",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "vomiting",
     "label": "Persistent vomiting after surgery",
     "kind": "yn",
     "points": 2,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Monaghan A. Detecting and managing deterioration in children. Paediatr Nurs 2005;17(1):32–5.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/15751446/"
    }
   ]
  },
  {
   "id": "bun-creatinine-ratio",
   "name": "BUN:Creatinine Ratio (Urea:Creatinine)",
   "short": "BUN/Cr ratio",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/bun-creatinine-ratio/",
   "summary": "BUN:creatinine ratio (both mg/dL) is normally 10–20. A ratio >20 suggests prerenal azotaemia, upper GI bleeding, high protein intake or catabolism; <10 suggests intrinsic renal disease, liver disease or low protein intake. In SI units (urea mmol/L ÷ creatinine µmol/L × 1000), 20 corresponds to about 81.",
   "formula": "Ratio = BUN (mg/dL) ÷ creatinine (mg/dL). SI ratio = urea (mmol/L) ÷ creatinine (µmol/L) × 1000; SI ≈ conventional × 4.04.",
   "inputs": [
    {
     "id": "bun",
     "label": "BUN / serum urea",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    }
   ],
   "references": [
    {
     "title": "Uchino S, Bellomo R, Goldsmith D. The meaning of the blood urea nitrogen/creatinine ratio in acute kidney injury. Clin Kidney J 2012;5:187–91.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/29497527/"
    }
   ]
  },
  {
   "id": "cage",
   "name": "CAGE Questionnaire for Alcohol Use",
   "short": "CAGE",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/cage/",
   "summary": "CAGE asks four yes/no questions about Cutting down, Annoyance at criticism, Guilt and Eye-openers. Two or more \"yes\" answers are clinically significant for alcohol use disorder; one \"yes\" warrants further questioning.",
   "formula": "One point per \"yes\": Cut down, Annoyed, Guilty, Eye-opener. Range 0–4; ≥2 positive.",
   "inputs": [
    {
     "id": "cut",
     "label": "Have you ever felt you should Cut down on your drinking?",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "annoyed",
     "label": "Have people Annoyed you by criticizing your drinking?",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "guilty",
     "label": "Have you ever felt bad or Guilty about your drinking?",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "eye",
     "label": "Have you ever had a drink first thing in the morning (Eye-opener) to steady your nerves or get rid of a hangover?",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Ewing JA. Detecting alcoholism. The CAGE questionnaire. JAMA 1984;252:1905–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/6471323/"
    }
   ]
  },
  {
   "id": "ldl-calculated",
   "name": "Calculated LDL Cholesterol (Friedewald and Sampson/NIH)",
   "short": "LDL-C",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/ldl-calculated/",
   "summary": "Friedewald LDL-C = total cholesterol − HDL − triglycerides/5 (mg/dL); invalid when triglycerides >400 mg/dL. The Sampson/NIH equation 2 is more accurate at high triglycerides (up to 800 mg/dL) and low LDL. LDL ≥190 mg/dL indicates severe hypercholesterolemia.",
   "formula": "Friedewald: LDL = TC − HDL − TG/5 (mg/dL; TG/2.2 in mmol/L) · Sampson/NIH eq. 2: LDL = TC/0.948 − HDL/0.971 − (TG/8.56 + TG × non-HDL/2140 − TG²/16100) − 9.44 (all mg/dL)",
   "inputs": [
    {
     "id": "tc",
     "label": "Total cholesterol",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 50,
     "max": 1000
    },
    {
     "id": "hdl",
     "label": "HDL cholesterol",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 5,
     "max": 200
    },
    {
     "id": "tg",
     "label": "Triglycerides",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 10,
     "max": 5000
    }
   ],
   "references": [
    {
     "title": "Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem 1972;18:499–502.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4337382/"
    },
    {
     "title": "Sampson M et al. A new equation for calculation of low-density lipoprotein cholesterol in patients with normolipidemia and/or hypertriglyceridemia. JAMA Cardiol 2020;5:540–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/32101259/"
    }
   ]
  },
  {
   "id": "serum-osmolality",
   "name": "Calculated Serum Osmolality",
   "short": "Calc osm",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/serum-osmolality/",
   "summary": "Calculated serum osmolality = 2 × Na + glucose/18 + BUN/2.8 (mg/dL), or in SI units 2 × Na + glucose + urea (mmol/L). Normal is about 275–295 mOsm/kg.",
   "formula": "Calc Osm = 2 × Na⁺ + glucose (mg/dL)/18 + BUN (mg/dL)/2.8. SI: 2 × Na⁺ + glucose (mmol/L) + urea (mmol/L). Effective osmolality = 2 × Na⁺ + glucose/18.",
   "inputs": [
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "glucose",
     "label": "Serum glucose",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 10,
     "max": 3000
    },
    {
     "id": "bun",
     "label": "BUN / serum urea",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300
    }
   ],
   "references": [
    {
     "title": "Dorwart WV, Chalmers L. Comparison of methods for calculating serum osmolality from chemical concentrations. Clin Chem 1975;21:190–4.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1112025/"
    }
   ]
  },
  {
   "id": "canadian-c-spine",
   "name": "Canadian C-Spine Rule",
   "short": "Canadian C-Spine",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/canadian-c-spine/",
   "summary": "For alert (GCS 15), stable adult trauma patients: image the cervical spine if any high-risk factor (age ≥65, dangerous mechanism, extremity paresthesias); otherwise, if a low-risk factor allows safe range-of-motion testing and the patient can actively rotate the neck 45° left and right, no imaging is needed.",
   "formula": "1) High risk (age ≥65, dangerous mechanism, paresthesias) → image. 2) Any low-risk factor (simple rear-end MVC, sitting in ED, ambulatory at any time, delayed neck pain, no midline tenderness)? If none → image. 3) Able to actively rotate 45° left and right → no imaging; unable → image.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 16,
     "max": 120
    },
    {
     "id": "mechanism",
     "label": "Dangerous mechanism",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "paresthesia",
     "label": "Paresthesias in extremities",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "rear_end",
     "label": "Simple rear-end MVC",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "sitting",
     "label": "Sitting position in ED",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "ambulatory",
     "label": "Ambulatory at any time since injury",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "delayed",
     "label": "Delayed (not immediate) onset of neck pain",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "no_midline",
     "label": "Absence of midline C-spine tenderness",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "rotate",
     "label": "Able to actively rotate neck 45° left and right",
     "kind": "yn",
     "points": 1,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Stiell IG et al. The Canadian C-spine rule for radiography in alert and stable trauma patients. JAMA 2001;286:1841–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11597285/"
    }
   ]
  },
  {
   "id": "canadian-ct-head",
   "name": "Canadian CT Head Rule",
   "short": "Canadian CT Head",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/canadian-ct-head/",
   "summary": "For adults with minor head injury (GCS 13–15 after witnessed loss of consciousness, amnesia or disorientation), CT is indicated if any of 5 high-risk (GCS <15 at 2 h, suspected open/depressed fracture, signs of basal skull fracture, ≥2 vomiting episodes, age ≥65) or 2 medium-risk factors (retrograde amnesia ≥30 min, dangerous mechanism) are present.",
   "formula": "High risk: GCS <15 at 2 h · suspected open/depressed skull fracture · sign of basal skull fracture · vomiting ≥2 · age ≥65. Medium risk: amnesia before impact ≥30 min · dangerous mechanism. Any factor → CT.",
   "inputs": [
    {
     "id": "gcs2h",
     "label": "GCS < 15 at 2 hours after injury",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "open_fx",
     "label": "Suspected open or depressed skull fracture",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "basal_fx",
     "label": "Any sign of basal skull fracture",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "vomit",
     "label": "Vomiting ≥ 2 episodes",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 16,
     "max": 120
    },
    {
     "id": "amnesia30",
     "label": "Retrograde amnesia ≥ 30 min before impact",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "mechanism",
     "label": "Dangerous mechanism (pedestrian struck, ejected, fall > 3 ft or 5 stairs)",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Stiell IG et al. The Canadian CT Head Rule for patients with minor head injury. Lancet 2001;357:1391–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11356436/"
    }
   ]
  },
  {
   "id": "canadian-syncope-risk-score",
   "name": "Canadian Syncope Risk Score (CSRS)",
   "short": "CSRS",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/canadian-syncope-risk-score/",
   "summary": "The Canadian Syncope Risk Score (−3 to 11) estimates 30-day serious adverse events after ED syncope from 9 predictors. Categories: very low (−3 to −2), low (−1 to 0), medium (1–3), high (4–5), very high (≥6); derivation risk ranged from 0.4% at −3 to 83.6% at 11.",
   "formula": "Vasovagal predisposition −1 · heart disease +1 · any ED SBP <90 or >180 +2 · troponin >99th pct +2 · QRS axis <−30° or >100° +1 · QRS >130 ms +1 · QTc >480 ms +2 · ED diagnosis vasovagal −2 / cardiac +2.",
   "inputs": [
    {
     "id": "vasovagal_predisp",
     "label": "Predisposition to vasovagal symptoms (warm crowded place, prolonged standing, fear, emotion, pain)",
     "kind": "yn",
     "points": -1
    },
    {
     "id": "heart_disease",
     "label": "History of heart disease (CAD, AF/flutter, CHF, valvular disease)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "sbp_abn",
     "label": "Any ED systolic BP < 90 or > 180 mmHg",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "troponin",
     "label": "Elevated troponin (> 99th percentile)",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "qrs_axis",
     "label": "Abnormal QRS axis (< −30° or > 100°)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "qrs_dur",
     "label": "QRS duration > 130 ms",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "qtc",
     "label": "Corrected QT > 480 ms",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "dx",
     "label": "ED diagnosis",
     "kind": "sel",
     "options": [
      {
       "value": "vasovagal",
       "label": "Vasovagal syncope",
       "points": -2
      },
      {
       "value": "neither",
       "label": "Neither (e.g. orthostatic or unknown)",
       "points": 0
      },
      {
       "value": "cardiac",
       "label": "Cardiac syncope",
       "points": 2
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Thiruganasambandamoorthy V et al. Development of the Canadian Syncope Risk Score to predict serious adverse events after emergency department assessment of syncope. CMAJ 2016;188:E289–98.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/27378464/"
    }
   ]
  },
  {
   "id": "caprini",
   "name": "Caprini Risk Assessment Model for VTE (2005)",
   "short": "Caprini",
   "category": "Surgery & Perioperative",
   "url": "https://askcalc.site/calc/caprini/",
   "summary": "The 2005 Caprini risk assessment model sums weighted VTE risk factors (1, 2, 3 or 5 points each) in surgical patients. Scores 0–1 are low risk, 2 moderate, 3–4 high and ≥5 highest risk; pharmacologic prophylaxis is generally indicated from 3 points (ACCP 2012 \"moderate\") unless bleeding risk is high.",
   "formula": "Age 41–60 = 1, 61–74 = 2, ≥75 = 3. 1 point: minor surgery, major surgery <1 mo, varicose veins, IBD, swollen legs, BMI >25, acute MI, CHF <1 mo, sepsis <1 mo, serious lung disease <1 mo, COPD, medical bed rest, other; women: OCP/HRT, pregnancy/postpartum, adverse obstetric history. 2 points: arthroscopic, malignancy, major surgery >45 min, laparoscopic >45 min, bed >72 h, cast <1 mo, central venous access. 3 points: prior DVT/PE, family history, factor V Leiden, prothrombin 20210A, homocysteine, lupus anticoagulant, anticardiolipin, HIT, other thrombophilia. 5 points: elective lower-extremity arthroplasty, hip/pelvis/leg fracture, stroke, multiple trauma, acute spinal cord injury (all <1 month).",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "minor_surg",
     "label": "Minor surgery planned",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "prior_major_surg",
     "label": "History of prior major surgery (< 1 month)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "varicose",
     "label": "Varicose veins",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "ibd",
     "label": "History of inflammatory bowel disease",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "swollen_legs",
     "label": "Swollen legs (current)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "obesity",
     "label": "Obesity (BMI > 25)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "ami",
     "label": "Acute myocardial infarction",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "chf",
     "label": "Congestive heart failure (< 1 month)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "sepsis",
     "label": "Sepsis (< 1 month)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "lung_dz",
     "label": "Serious lung disease incl. pneumonia (< 1 month)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "copd",
     "label": "Abnormal pulmonary function (COPD)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "bed_rest_med",
     "label": "Medical patient currently at bed rest",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "other_rf",
     "label": "Other risk factor (clinician judged)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "ocp_hrt",
     "label": "Women: oral contraceptives or hormone replacement therapy",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "pregnancy",
     "label": "Women: pregnancy or postpartum (< 1 month)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "ob_hx",
     "label": "Women: unexplained stillbirth, ≥3 spontaneous abortions, or premature birth with toxemia / growth-restricted infant",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "arthroscopic",
     "label": "Arthroscopic surgery",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "malignancy",
     "label": "Malignancy (present or previous)",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "major_surg",
     "label": "Major surgery (> 45 minutes)",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "lap_surg",
     "label": "Laparoscopic surgery (> 45 minutes)",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "confined_bed",
     "label": "Patient confined to bed (> 72 hours)",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "cast",
     "label": "Immobilizing plaster cast (< 1 month)",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "cvc",
     "label": "Central venous access",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "vte_hx",
     "label": "History of DVT/PE",
     "kind": "yn",
     "points": 3,
     "optional": true
    },
    {
     "id": "fam_hx",
     "label": "Family history of thrombosis",
     "kind": "yn",
     "points": 3,
     "optional": true
    },
    {
     "id": "fvl",
     "label": "Positive factor V Leiden",
     "kind": "yn",
     "points": 3,
     "optional": true
    },
    {
     "id": "pt20210",
     "label": "Positive prothrombin 20210A",
     "kind": "yn",
     "points": 3,
     "optional": true
    },
    {
     "id": "homocysteine",
     "label": "Elevated serum homocysteine",
     "kind": "yn",
     "points": 3,
     "optional": true
    },
    {
     "id": "lupus_ac",
     "label": "Positive lupus anticoagulant",
     "kind": "yn",
     "points": 3,
     "optional": true
    },
    {
     "id": "acl",
     "label": "Elevated anticardiolipin antibodies",
     "kind": "yn",
     "points": 3,
     "optional": true
    },
    {
     "id": "hit",
     "label": "Heparin-induced thrombocytopenia (HIT)",
     "kind": "yn",
     "points": 3,
     "optional": true
    },
    {
     "id": "other_thrombophilia",
     "label": "Other congenital or acquired thrombophilia",
     "kind": "yn",
     "points": 3,
     "optional": true
    },
    {
     "id": "arthroplasty",
     "label": "Elective major lower-extremity arthroplasty",
     "kind": "yn",
     "points": 5,
     "optional": true
    },
    {
     "id": "fracture",
     "label": "Hip, pelvis or leg fracture (< 1 month)",
     "kind": "yn",
     "points": 5,
     "optional": true
    },
    {
     "id": "stroke",
     "label": "Stroke (< 1 month)",
     "kind": "yn",
     "points": 5,
     "optional": true
    },
    {
     "id": "multi_trauma",
     "label": "Multiple trauma (< 1 month)",
     "kind": "yn",
     "points": 5,
     "optional": true
    },
    {
     "id": "sci",
     "label": "Acute spinal cord injury with paralysis (< 1 month)",
     "kind": "yn",
     "points": 5,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Caprini JA. Thrombosis risk assessment as a guide to quality patient care. Dis Mon 2005;51:70–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/15900257/"
    },
    {
     "title": "Gould MK et al. Prevention of VTE in nonorthopedic surgical patients: ACCP 9th ed. Chest 2012;141(2 Suppl):e227S–e277S.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/22315263/"
    }
   ]
  },
  {
   "id": "cardiac-output-fick",
   "name": "Cardiac Output by the Fick Principle",
   "short": "Fick CO",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/cardiac-output-fick/",
   "summary": "Fick cardiac output = O₂ consumption ÷ arteriovenous O₂ content difference, where O₂ content ≈ 1.34 × Hb × saturation (× 10 per litre). With estimated VO₂ of 125 mL/min/m², normal CO is 4–8 L/min and cardiac index 2.5–4.0 L/min/m²; CI <2.2 suggests low output.",
   "formula": "CO (L/min) = VO₂ (mL/min) ÷ [1.34 × Hb (g/dL) × (SaO₂ − SvO₂) × 10]. Estimated VO₂ = 125 mL/min/m² × BSA. CI = CO ÷ BSA.",
   "inputs": [
    {
     "id": "hgb",
     "label": "Haemoglobin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 2,
     "max": 25
    },
    {
     "id": "sao2",
     "label": "Arterial O₂ saturation",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 30,
     "max": 100
    },
    {
     "id": "svo2",
     "label": "Mixed venous O₂ saturation (PA)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 5,
     "max": 99
    },
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 0.3,
     "max": 400
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 30,
     "max": 250
    },
    {
     "id": "vo2",
     "label": "Measured VO₂ (blank = 125 mL/min/m²)",
     "kind": "num",
     "unit": "mL/min",
     "units": [
      "mL/min"
     ],
     "min": 50,
     "max": 2000,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "LaFarge CG, Miettinen OS. The estimation of oxygen consumption. Cardiovasc Res 1970;4:23–30.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/5416840/"
    }
   ]
  },
  {
   "id": "centor-mcisaac",
   "name": "Centor Score (Modified / McIsaac) for Strep Pharyngitis",
   "short": "Centor / McIsaac",
   "category": "Infectious Disease",
   "url": "https://askcalc.site/calc/centor-mcisaac/",
   "summary": "The McIsaac (modified Centor) score estimates the likelihood of group A streptococcal pharyngitis: 1 point each for fever >38 °C, absent cough, tender anterior cervical nodes and tonsillar swelling/exudate, +1 for age 3–14 and −1 for age ≥45. Scores ≤1 need no testing or antibiotics; 2–3 warrant a rapid strep test or culture; ≥4 warrants testing (or empiric treatment in some guidelines).",
   "formula": "Fever >38 °C +1 · absence of cough +1 · tender anterior cervical nodes +1 · tonsillar swelling/exudate +1 · age 3–14 +1 · age 15–44 0 · age ≥45 −1",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 3,
     "max": 120
    },
    {
     "id": "fever",
     "label": "Temperature >38 °C (100.4 °F)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "no_cough",
     "label": "Absence of cough",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "nodes",
     "label": "Tender/swollen anterior cervical lymph nodes",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "tonsils",
     "label": "Tonsillar swelling or exudate",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "McIsaac WJ et al. A clinical score to reduce unnecessary antibiotic use in patients with sore throat. CMAJ 1998;158:75–83.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9475915/"
    },
    {
     "title": "Centor RM et al. The diagnosis of strep throat in adults in the emergency room. Med Decis Making 1981;1:239–46.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/6763125/"
    }
   ]
  },
  {
   "id": "cha2ds2-vasc",
   "name": "CHA2DS2-VASc Score for Atrial Fibrillation Stroke Risk",
   "short": "CHA2DS2-VASc",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/cha2ds2-vasc/",
   "summary": "CHA₂DS₂-VASc estimates annual stroke risk in non-valvular atrial fibrillation (0–9 points). Oral anticoagulation is recommended at ≥2 in men and ≥3 in women, and considered at 1 (men) or 2 (women).",
   "formula": "C: CHF 1 · H: hypertension 1 · A₂: age ≥75 2 · D: diabetes 1 · S₂: stroke/TIA/TE 2 · V: vascular disease 1 · A: age 65–74 1 · Sc: female 1",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "chf",
     "label": "Congestive heart failure history",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "htn",
     "label": "Hypertension",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "stroke",
     "label": "Prior stroke, TIA or thromboembolism",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "vascular",
     "label": "Vascular disease (prior MI, PAD, aortic plaque)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "dm",
     "label": "Diabetes mellitus",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Lip GYH et al. Refining clinical risk stratification for predicting stroke and thromboembolism in AF. Chest 2010;137:263–72.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/19762550/"
    },
    {
     "title": "2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/38033089/"
    }
   ]
  },
  {
   "id": "chads-65",
   "name": "CHADS-65 Algorithm (Canadian Cardiovascular Society) for AF Anticoagulation",
   "short": "CHADS-65",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/chads-65/",
   "summary": "The CCS \"CHADS-65\" algorithm recommends oral anticoagulation for AF if age ≥65 or any CHADS₂ risk factor (heart failure, hypertension, diabetes, prior stroke/TIA) is present; otherwise antiplatelet therapy if there is coronary or peripheral arterial disease; otherwise no antithrombotic.",
   "formula": "Step 1: age ≥ 65 → OAC · Step 2: any of CHF, hypertension, diabetes, prior stroke/TIA → OAC · Step 3: CAD or PAD → antiplatelet · otherwise no antithrombotic",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "chf",
     "label": "Congestive heart failure",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "htn",
     "label": "Hypertension",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "dm",
     "label": "Diabetes mellitus",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "stroke",
     "label": "Prior stroke or TIA",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "cad_pad",
     "label": "Coronary or peripheral arterial disease",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Andrade JG et al. 2020 CCS/CHRS Comprehensive Guidelines for the Management of Atrial Fibrillation. Can J Cardiol 2020;36:1847–1948.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/33191198/"
    },
    {
     "title": "Macle L et al. 2016 Focused Update of the CCS Guidelines for the Management of Atrial Fibrillation. Can J Cardiol 2016;32:1170–85.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/27609430/"
    }
   ]
  },
  {
   "id": "chads2",
   "name": "CHADS2 Score for Atrial Fibrillation Stroke Risk",
   "short": "CHADS2",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/chads2/",
   "summary": "CHADS₂ estimates annual stroke risk in non-valvular atrial fibrillation (0–6 points): CHF, hypertension, age ≥75, diabetes 1 point each; prior stroke/TIA 2 points. It has largely been replaced by CHA₂DS₂-VASc but still drives the Canadian CHADS-65 algorithm.",
   "formula": "C: CHF 1 · H: hypertension 1 · A: age ≥ 75 1 · D: diabetes 1 · S₂: prior stroke/TIA 2",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "chf",
     "label": "Congestive heart failure",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "htn",
     "label": "Hypertension",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "dm",
     "label": "Diabetes mellitus",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "stroke",
     "label": "Prior stroke or TIA",
     "kind": "yn",
     "points": 2
    }
   ],
   "references": [
    {
     "title": "Gage BF et al. Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation. JAMA 2001;285:2864–70.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11401607/"
    }
   ]
  },
  {
   "id": "charlson",
   "name": "Charlson Comorbidity Index (CCI)",
   "short": "Charlson CCI",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/charlson/",
   "summary": "The age-adjusted Charlson Comorbidity Index weights 19 conditions (1–6 points each) plus 1 point per decade over 49, and estimates 10-year survival as 0.983^(e^(0.9 × CCI)). A score of 0 predicts 98% 10-year survival; 5 predicts about 21%.",
   "formula": "1 point: MI, CHF, PVD, cerebrovascular disease, dementia, chronic pulmonary disease, connective tissue disease, peptic ulcer, mild liver disease, uncomplicated diabetes. 2 points: hemiplegia, moderate–severe CKD, diabetes with end-organ damage, localized solid tumour, leukemia, lymphoma. 3 points: moderate–severe liver disease. 6 points: metastatic solid tumour, AIDS. Age: 50–59 +1, 60–69 +2, 70–79 +3, ≥80 +4. 10-year survival = 0.983^(e^(0.9 × CCI)).",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "mi",
     "label": "Myocardial infarction (history)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "chf",
     "label": "Congestive heart failure",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "pvd",
     "label": "Peripheral vascular disease (incl. aortic aneurysm ≥6 cm)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "cvd",
     "label": "Cerebrovascular disease (CVA with mild or no residua, or TIA)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "dementia",
     "label": "Dementia",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "copd",
     "label": "Chronic pulmonary disease",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "ctd",
     "label": "Connective tissue disease",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "pud",
     "label": "Peptic ulcer disease",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "hemiplegia",
     "label": "Hemiplegia",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "ckd",
     "label": "Moderate to severe chronic kidney disease (Cr >3 mg/dL, dialysis, transplant, uremia)",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "leukemia",
     "label": "Leukemia",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "lymphoma",
     "label": "Lymphoma",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "aids",
     "label": "AIDS (not just HIV positive)",
     "kind": "yn",
     "points": 6,
     "optional": true
    },
    {
     "id": "liver",
     "label": "Liver disease",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "mild",
       "label": "Mild (chronic hepatitis or cirrhosis without portal hypertension)",
       "points": 1
      },
      {
       "value": "severe",
       "label": "Moderate to severe (cirrhosis with portal hypertension ± variceal bleeding)",
       "points": 3
      }
     ],
     "optional": true
    },
    {
     "id": "dm",
     "label": "Diabetes mellitus",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None or diet-controlled",
       "points": 0
      },
      {
       "value": "uncomplicated",
       "label": "Uncomplicated (treated)",
       "points": 1
      },
      {
       "value": "end-organ",
       "label": "With end-organ damage (retinopathy, nephropathy, neuropathy)",
       "points": 2
      }
     ],
     "optional": true
    },
    {
     "id": "tumor",
     "label": "Solid tumour (within 5 years)",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "localized",
       "label": "Localized solid tumour",
       "points": 2
      },
      {
       "value": "metastatic",
       "label": "Metastatic solid tumour",
       "points": 6
      }
     ],
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Charlson ME et al. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987;40:373–83.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3558716/"
    },
    {
     "title": "Charlson M et al. Validation of a combined comorbidity index. J Clin Epidemiol 1994;47:1245–51.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/7722560/"
    }
   ]
  },
  {
   "id": "child-pugh",
   "name": "Child-Pugh Score for Cirrhosis",
   "short": "Child-Pugh",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/child-pugh/",
   "summary": "Child-Pugh grades cirrhosis severity from bilirubin, albumin, INR, ascites and encephalopathy (5–15 points): class A 5–6 (well compensated), B 7–9 (significant functional compromise), C 10–15 (decompensated). It guides prognosis, drug dosing and surgical risk.",
   "formula": "Bilirubin <2 / 2–3 / >3 mg/dL (<34 / 34–50 / >50 µmol/L) = 1/2/3 (PBC/PSC: <4 / 4–10 / >10). Albumin >3.5 / 2.8–3.5 / <2.8 g/dL = 1/2/3. INR <1.7 / 1.7–2.3 / >2.3 = 1/2/3. Ascites none / mild / moderate–severe = 1/2/3. Encephalopathy none / grade 1–2 / grade 3–4 = 1/2/3.",
   "inputs": [
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 7
    },
    {
     "id": "inr",
     "label": "INR",
     "kind": "num",
     "min": 0.5,
     "max": 20
    },
    {
     "id": "ascites",
     "label": "Ascites",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 1
      },
      {
       "value": "mild",
       "label": "Mild (slight, or controlled with diuretics)",
       "points": 2
      },
      {
       "value": "severe",
       "label": "Moderate–severe (tense or refractory)",
       "points": 3
      }
     ]
    },
    {
     "id": "enceph",
     "label": "Hepatic encephalopathy",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 1
      },
      {
       "value": "g12",
       "label": "Grade 1–2 (or controlled with medication)",
       "points": 2
      },
      {
       "value": "g34",
       "label": "Grade 3–4 (or refractory)",
       "points": 3
      }
     ]
    },
    {
     "id": "cholestatic",
     "label": "Cholestatic disease (PBC/PSC): use bilirubin cut-offs 4 and 10 mg/dL",
     "kind": "yn",
     "points": 0,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Pugh RN et al. Transection of the oesophagus for bleeding oesophageal varices. Br J Surg 1973;60:646–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4541913/"
    }
   ]
  },
  {
   "id": "ciwa-ar",
   "name": "CIWA-Ar Alcohol Withdrawal Scale",
   "short": "CIWA-Ar",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/ciwa-ar/",
   "summary": "The CIWA-Ar rates 10 alcohol withdrawal signs (nine scored 0–7, orientation 0–4), total 0–67. Scores below 10 usually need no medication; 10–15 is moderate withdrawal, and ≥16 is severe withdrawal with higher risk of seizures and delirium tremens.",
   "formula": "Nausea/vomiting, tremor, paroxysmal sweats, anxiety, agitation, tactile, auditory and visual disturbances, headache (each 0–7) + orientation (0–4). Range 0–67.",
   "inputs": [
    {
     "id": "nausea",
     "label": "Nausea and vomiting",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No nausea and no vomiting",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Mild nausea with no vomiting",
       "points": 1
      },
      {
       "value": "2",
       "label": "2",
       "points": 2
      },
      {
       "value": "3",
       "label": "3",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Intermittent nausea with dry heaves",
       "points": 4
      },
      {
       "value": "5",
       "label": "5",
       "points": 5
      },
      {
       "value": "6",
       "label": "6",
       "points": 6
      },
      {
       "value": "7",
       "label": "7: Constant nausea, frequent dry heaves and vomiting",
       "points": 7
      }
     ]
    },
    {
     "id": "tremor",
     "label": "Tremor (arms extended, fingers spread)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No tremor",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Not visible, but can be felt fingertip to fingertip",
       "points": 1
      },
      {
       "value": "2",
       "label": "2",
       "points": 2
      },
      {
       "value": "3",
       "label": "3",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Moderate, with arms extended",
       "points": 4
      },
      {
       "value": "5",
       "label": "5",
       "points": 5
      },
      {
       "value": "6",
       "label": "6",
       "points": 6
      },
      {
       "value": "7",
       "label": "7: Severe, even with arms not extended",
       "points": 7
      }
     ]
    },
    {
     "id": "sweats",
     "label": "Paroxysmal sweats",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No sweat visible",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Barely perceptible sweating, palms moist",
       "points": 1
      },
      {
       "value": "2",
       "label": "2",
       "points": 2
      },
      {
       "value": "3",
       "label": "3",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Beads of sweat obvious on forehead",
       "points": 4
      },
      {
       "value": "5",
       "label": "5",
       "points": 5
      },
      {
       "value": "6",
       "label": "6",
       "points": 6
      },
      {
       "value": "7",
       "label": "7: Drenching sweats",
       "points": 7
      }
     ]
    },
    {
     "id": "anxiety",
     "label": "Anxiety",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No anxiety, at ease",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Mildly anxious",
       "points": 1
      },
      {
       "value": "2",
       "label": "2",
       "points": 2
      },
      {
       "value": "3",
       "label": "3",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Moderately anxious, or guarded, so anxiety is inferred",
       "points": 4
      },
      {
       "value": "5",
       "label": "5",
       "points": 5
      },
      {
       "value": "6",
       "label": "6",
       "points": 6
      },
      {
       "value": "7",
       "label": "7: Equivalent to acute panic states",
       "points": 7
      }
     ]
    },
    {
     "id": "agitation",
     "label": "Agitation",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Normal activity",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Somewhat more than normal activity",
       "points": 1
      },
      {
       "value": "2",
       "label": "2",
       "points": 2
      },
      {
       "value": "3",
       "label": "3",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Moderately fidgety and restless",
       "points": 4
      },
      {
       "value": "5",
       "label": "5",
       "points": 5
      },
      {
       "value": "6",
       "label": "6",
       "points": 6
      },
      {
       "value": "7",
       "label": "7: Paces back and forth or constantly thrashes about",
       "points": 7
      }
     ]
    },
    {
     "id": "tactile",
     "label": "Tactile disturbances",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: None",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Very mild itching, pins and needles, burning or numbness",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Mild itching, pins and needles, burning or numbness",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Moderate itching, pins and needles, burning or numbness",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Moderately severe hallucinations",
       "points": 4
      },
      {
       "value": "5",
       "label": "5: Severe hallucinations",
       "points": 5
      },
      {
       "value": "6",
       "label": "6: Extremely severe hallucinations",
       "points": 6
      },
      {
       "value": "7",
       "label": "7: Continuous hallucinations",
       "points": 7
      }
     ]
    },
    {
     "id": "auditory",
     "label": "Auditory disturbances",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Not present",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Very mild harshness or ability to frighten",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Mild harshness or ability to frighten",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Moderate harshness or ability to frighten",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Moderately severe hallucinations",
       "points": 4
      },
      {
       "value": "5",
       "label": "5: Severe hallucinations",
       "points": 5
      },
      {
       "value": "6",
       "label": "6: Extremely severe hallucinations",
       "points": 6
      },
      {
       "value": "7",
       "label": "7: Continuous hallucinations",
       "points": 7
      }
     ]
    },
    {
     "id": "visual",
     "label": "Visual disturbances",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Not present",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Very mild sensitivity",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Mild sensitivity",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Moderate sensitivity",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Moderately severe hallucinations",
       "points": 4
      },
      {
       "value": "5",
       "label": "5: Severe hallucinations",
       "points": 5
      },
      {
       "value": "6",
       "label": "6: Extremely severe hallucinations",
       "points": 6
      },
      {
       "value": "7",
       "label": "7: Continuous hallucinations",
       "points": 7
      }
     ]
    },
    {
     "id": "headache",
     "label": "Headache, fullness in head",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Not present",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Very mild",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Mild",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Moderate",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Moderately severe",
       "points": 4
      },
      {
       "value": "5",
       "label": "5: Severe",
       "points": 5
      },
      {
       "value": "6",
       "label": "6: Very severe",
       "points": 6
      },
      {
       "value": "7",
       "label": "7: Extremely severe",
       "points": 7
      }
     ]
    },
    {
     "id": "orientation",
     "label": "Orientation and clouding of sensorium",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Oriented and can do serial additions",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Cannot do serial additions or is uncertain about date",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Disoriented for date by no more than 2 calendar days",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Disoriented for date by more than 2 calendar days",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Disoriented for place and/or person",
       "points": 4
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Sullivan JT et al. Assessment of alcohol withdrawal: the revised Clinical Institute Withdrawal Assessment for Alcohol scale (CIWA-Ar). Br J Addict 1989;84:1353–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/2597811/"
    }
   ]
  },
  {
   "id": "cdai-ra",
   "name": "Clinical Disease Activity Index (CDAI) for Rheumatoid Arthritis",
   "short": "CDAI (RA)",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/cdai-ra/",
   "summary": "The CDAI is the sum of 28-joint tender and swollen counts plus patient and evaluator global assessments (each 0–10), range 0–76, needing no lab test. Remission ≤2.8, low ≤10, moderate ≤22, high >22.",
   "formula": "CDAI = TJC28 + SJC28 + patient global assessment (0–10) + evaluator global assessment (0–10)",
   "inputs": [
    {
     "id": "tjc",
     "label": "Tender joint count (28 joints)",
     "kind": "num",
     "unit": "joints",
     "units": [
      "joints"
     ],
     "min": 0,
     "max": 28
    },
    {
     "id": "sjc",
     "label": "Swollen joint count (28 joints)",
     "kind": "num",
     "unit": "joints",
     "units": [
      "joints"
     ],
     "min": 0,
     "max": 28
    },
    {
     "id": "ptga",
     "label": "Patient global assessment of disease activity (0–10)",
     "kind": "num",
     "min": 0,
     "max": 10
    },
    {
     "id": "ega",
     "label": "Evaluator (physician) global assessment of disease activity (0–10)",
     "kind": "num",
     "min": 0,
     "max": 10
    }
   ],
   "references": [
    {
     "title": "Aletaha D et al. Acute phase reactants add little to composite disease activity indices for rheumatoid arthritis: validation of a clinical activity score. Arthritis Res Ther 2005;7:R796–806.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/15987481/"
    },
    {
     "title": "Aletaha D, Smolen J. The SDAI and the CDAI: a review of their usefulness and validity in rheumatoid arthritis. Clin Exp Rheumatol 2005;23(5 Suppl 39):S100–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16273793/"
    }
   ]
  },
  {
   "id": "corrected-calcium",
   "name": "Corrected Calcium for Albumin",
   "short": "Corrected Ca",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/corrected-calcium/",
   "summary": "Corrected calcium = measured calcium + 0.8 × (4.0 − albumin g/dL), or in SI units Ca + 0.02 × (40 − albumin g/L) mmol/L. Normal is about 8.5–10.5 mg/dL (2.10–2.60 mmol/L); measure ionised calcium when it matters.",
   "formula": "Corrected Ca (mg/dL) = Ca + 0.8 × (4.0 − albumin g/dL). SI: Corrected Ca (mmol/L) = Ca + 0.02 × (40 − albumin g/L).",
   "inputs": [
    {
     "id": "ca",
     "label": "Total serum calcium",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 3,
     "max": 20
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 6.5
    }
   ],
   "references": [
    {
     "title": "Payne RB et al. Interpretation of serum calcium in patients with abnormal serum proteins. Br Med J 1973;4:643–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4758544/"
    }
   ]
  },
  {
   "id": "corrected-phenytoin",
   "name": "Corrected Phenytoin Level (Sheiner-Tozer / Winter-Tozer)",
   "short": "Corrected phenytoin",
   "category": "Pharmacology & Dosing",
   "url": "https://askcalc.site/calc/corrected-phenytoin/",
   "summary": "Corrected phenytoin = measured total level ÷ (0.2 × albumin g/dL + 0.1); with CrCl <10 mL/min or ESRD, ÷ (0.1 × albumin + 0.1). The therapeutic total range is 10–20 mg/L; a free phenytoin level is preferred when available.",
   "formula": "Corrected = measured ÷ (0.2 × albumin + 0.1)   ·   CrCl <10: measured ÷ (0.1 × albumin + 0.1)   ·   albumin in g/dL",
   "inputs": [
    {
     "id": "pht",
     "label": "Measured total phenytoin",
     "kind": "num",
     "unit": "mg/L",
     "units": [
      "mg/L",
      "µg/mL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 100
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 6.5
    },
    {
     "id": "renal",
     "label": "Renal function",
     "kind": "sel",
     "options": [
      {
       "value": "normal",
       "label": "CrCl ≥ 10 mL/min"
      },
      {
       "value": "esrd",
       "label": "CrCl < 10 mL/min / ESRD / dialysis"
      }
     ],
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Liponi DF, Winter ME, Tozer TN. Renal function and therapeutic concentrations of phenytoin. Neurology 1984;34:395–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/6538287/"
    },
    {
     "title": "Anderson GD et al. Revised Winter-Tozer equation for normalized phenytoin concentrations in trauma and elderly patients with hypoalbuminemia. Ann Pharmacother 1997;31:279–84.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9066931/"
    }
   ]
  },
  {
   "id": "qtc",
   "name": "Corrected QT Interval (QTc)",
   "short": "QTc",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/qtc/",
   "summary": "Corrects the QT interval for heart rate. Bazett: QT/√RR (primary); Fridericia: QT/∛RR; Framingham: QT + 154 × (1 − RR); Hodges: QT + 1.75 × (HR − 60). QTc ≥450 ms (men) or ≥460 ms (women) is prolonged; ≥500 ms markedly raises torsades risk.",
   "formula": "RR (s) = 60 ÷ HR · Bazett: QT ÷ √RR · Fridericia: QT ÷ ∛RR · Framingham: QT + 154 × (1 − RR) · Hodges: QT + 1.75 × (HR − 60) · Rautaharju: QT × (120 + HR) ÷ 180   (QT in ms)",
   "inputs": [
    {
     "id": "qt",
     "label": "QT interval",
     "kind": "num",
     "unit": "ms",
     "units": [
      "ms",
      "s"
     ],
     "min": 150,
     "max": 800
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 250
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ],
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Rautaharju PM et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram, part IV: the ST segment, T and U waves, and the QT interval. J Am Coll Cardiol 2009;53:982–91.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/19281931/"
    },
    {
     "title": "Sagie A et al. An improved method for adjusting the QT interval for heart rate (the Framingham Heart Study). Am J Cardiol 1992;70:797–801.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1519533/"
    },
    {
     "title": "Luo S et al. A comparison of commonly used QT correction formulae: the effect of heart rate on the QTc of normal ECGs. J Electrocardiol 2004;37 Suppl:81–90.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/15534815/"
    }
   ]
  },
  {
   "id": "corrected-sodium",
   "name": "Corrected Sodium in Hyperglycemia",
   "short": "Corrected Na",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/corrected-sodium/",
   "summary": "In hyperglycaemia, serum sodium falls as water shifts out of cells. Corrected Na = Na + 1.6 × (glucose − 100)/100 mg/dL (Katz) or + 2.4 per 100 mg/dL (Hillier, more accurate at very high glucose). In SI, add 1.6 or 2.4 per 5.6 mmol/L of glucose above 5.6.",
   "formula": "Katz: Na + 1.6 × (glucose mg/dL − 100) ÷ 100. Hillier: Na + 2.4 × (glucose − 100) ÷ 100. SI: glucose mg/dL = mmol/L × 18. No correction applied when glucose ≤100 mg/dL (5.6 mmol/L).",
   "inputs": [
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "glucose",
     "label": "Serum glucose",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 10,
     "max": 3000
    }
   ],
   "references": [
    {
     "title": "Katz MA. Hyperglycemia-induced hyponatremia — calculation of expected serum sodium depression. N Engl J Med 1973;289:843–4.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4763428/"
    },
    {
     "title": "Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med 1999;106:399–403.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10225241/"
    }
   ]
  },
  {
   "id": "steroid-conversion",
   "name": "Corticosteroid Equivalent Dose Conversion",
   "short": "Steroid conversion",
   "category": "Pharmacology & Dosing",
   "url": "https://askcalc.site/calc/steroid-conversion/",
   "summary": "Converts a systemic glucocorticoid dose to the equivalent dose of another using approximate anti-inflammatory equivalents: prednisone 5 mg = prednisolone 5 mg = methylprednisolone 4 mg = triamcinolone 4 mg = hydrocortisone 20 mg = cortisone 25 mg = dexamethasone 0.75 mg = betamethasone 0.6 mg.",
   "formula": "Target dose = current dose ÷ equivalent dose(current) × equivalent dose(target). Equivalents (mg): cortisone 25, hydrocortisone 20, prednisone 5, prednisolone 5, methylprednisolone 4, triamcinolone 4, dexamethasone 0.75, betamethasone 0.6.",
   "inputs": [
    {
     "id": "from",
     "label": "Current steroid",
     "kind": "sel",
     "options": [
      {
       "value": "hydrocortisone",
       "label": "Hydrocortisone"
      },
      {
       "value": "cortisone",
       "label": "Cortisone"
      },
      {
       "value": "prednisone",
       "label": "Prednisone"
      },
      {
       "value": "prednisolone",
       "label": "Prednisolone"
      },
      {
       "value": "methylprednisolone",
       "label": "Methylprednisolone"
      },
      {
       "value": "triamcinolone",
       "label": "Triamcinolone"
      },
      {
       "value": "dexamethasone",
       "label": "Dexamethasone"
      },
      {
       "value": "betamethasone",
       "label": "Betamethasone"
      }
     ]
    },
    {
     "id": "dose",
     "label": "Current dose (mg)",
     "kind": "num",
     "min": 0,
     "max": 5000
    },
    {
     "id": "to",
     "label": "Target steroid",
     "kind": "sel",
     "options": [
      {
       "value": "hydrocortisone",
       "label": "Hydrocortisone"
      },
      {
       "value": "cortisone",
       "label": "Cortisone"
      },
      {
       "value": "prednisone",
       "label": "Prednisone"
      },
      {
       "value": "prednisolone",
       "label": "Prednisolone"
      },
      {
       "value": "methylprednisolone",
       "label": "Methylprednisolone"
      },
      {
       "value": "triamcinolone",
       "label": "Triamcinolone"
      },
      {
       "value": "dexamethasone",
       "label": "Dexamethasone"
      },
      {
       "value": "betamethasone",
       "label": "Betamethasone"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Liu D et al. A practical guide to the monitoring and management of the complications of systemic corticosteroid therapy. Allergy Asthma Clin Immunol 2013;9:30 (Table 3).",
     "url": "https://pubmed.ncbi.nlm.nih.gov/23947590/"
    }
   ]
  },
  {
   "id": "cows",
   "name": "COWS Clinical Opiate Withdrawal Scale",
   "short": "COWS",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/cows/",
   "summary": "The COWS rates 11 opioid withdrawal signs, total 0–48: 5–12 mild, 13–24 moderate, 25–36 moderately severe and >36 severe. It is commonly used to time buprenorphine induction, typically once the score is about 8–12 or higher.",
   "formula": "Pulse (≤80 = 0, 81–100 = 1, 101–120 = 2, >120 = 4) + sweating 0–4 + restlessness 0–5 + pupils 0–5 + bone/joint aches 0–4 + runny nose/tearing 0–4 + GI upset 0–5 + tremor 0–4 + yawning 0–4 + anxiety/irritability 0–4 + gooseflesh 0–5. Range 0–48.",
   "inputs": [
    {
     "id": "hr",
     "label": "Resting pulse rate (after sitting 1 minute)",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 250
    },
    {
     "id": "sweating",
     "label": "Sweating (past ½ h, not due to room temperature or activity)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No report of chills or flushing",
       "points": 0
      },
      {
       "value": "1",
       "label": "Subjective report of chills or flushing",
       "points": 1
      },
      {
       "value": "2",
       "label": "Flushed or observable moistness on face",
       "points": 2
      },
      {
       "value": "3",
       "label": "Beads of sweat on brow or face",
       "points": 3
      },
      {
       "value": "4",
       "label": "Sweat streaming off face",
       "points": 4
      }
     ]
    },
    {
     "id": "restlessness",
     "label": "Restlessness (observed during assessment)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Able to sit still",
       "points": 0
      },
      {
       "value": "1",
       "label": "Reports difficulty sitting still, but is able to do so",
       "points": 1
      },
      {
       "value": "3",
       "label": "Frequent shifting or extraneous movements of legs/arms",
       "points": 3
      },
      {
       "value": "5",
       "label": "Unable to sit still for more than a few seconds",
       "points": 5
      }
     ]
    },
    {
     "id": "pupils",
     "label": "Pupil size",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Pupils pinned or normal size for room light",
       "points": 0
      },
      {
       "value": "1",
       "label": "Pupils possibly larger than normal for room light",
       "points": 1
      },
      {
       "value": "2",
       "label": "Pupils moderately dilated",
       "points": 2
      },
      {
       "value": "5",
       "label": "Pupils so dilated that only the rim of the iris is visible",
       "points": 5
      }
     ]
    },
    {
     "id": "aches",
     "label": "Bone or joint aches (new)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not present",
       "points": 0
      },
      {
       "value": "1",
       "label": "Mild diffuse discomfort",
       "points": 1
      },
      {
       "value": "2",
       "label": "Severe diffuse aching of joints/muscles",
       "points": 2
      },
      {
       "value": "4",
       "label": "Rubbing joints or muscles and unable to sit still because of discomfort",
       "points": 4
      }
     ]
    },
    {
     "id": "rhinorrhea",
     "label": "Runny nose or tearing (not from cold or allergy)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not present",
       "points": 0
      },
      {
       "value": "1",
       "label": "Nasal stuffiness or unusually moist eyes",
       "points": 1
      },
      {
       "value": "2",
       "label": "Nose running or tearing",
       "points": 2
      },
      {
       "value": "4",
       "label": "Nose constantly running or tears streaming down cheeks",
       "points": 4
      }
     ]
    },
    {
     "id": "gi",
     "label": "GI upset (past ½ h)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No GI symptoms",
       "points": 0
      },
      {
       "value": "1",
       "label": "Stomach cramps",
       "points": 1
      },
      {
       "value": "2",
       "label": "Nausea or loose stool",
       "points": 2
      },
      {
       "value": "3",
       "label": "Vomiting or diarrhea",
       "points": 3
      },
      {
       "value": "5",
       "label": "Multiple episodes of diarrhea or vomiting",
       "points": 5
      }
     ]
    },
    {
     "id": "tremor",
     "label": "Tremor (outstretched hands)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No tremor",
       "points": 0
      },
      {
       "value": "1",
       "label": "Tremor can be felt, but not observed",
       "points": 1
      },
      {
       "value": "2",
       "label": "Slight tremor observable",
       "points": 2
      },
      {
       "value": "4",
       "label": "Gross tremor or muscle twitching",
       "points": 4
      }
     ]
    },
    {
     "id": "yawning",
     "label": "Yawning (during assessment)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No yawning",
       "points": 0
      },
      {
       "value": "1",
       "label": "Yawning once or twice during assessment",
       "points": 1
      },
      {
       "value": "2",
       "label": "Yawning three or more times during assessment",
       "points": 2
      },
      {
       "value": "4",
       "label": "Yawning several times per minute",
       "points": 4
      }
     ]
    },
    {
     "id": "anxiety",
     "label": "Anxiety or irritability",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "None",
       "points": 0
      },
      {
       "value": "1",
       "label": "Reports increasing irritability or anxiousness",
       "points": 1
      },
      {
       "value": "2",
       "label": "Obviously irritable or anxious",
       "points": 2
      },
      {
       "value": "4",
       "label": "So irritable or anxious that participation in the assessment is difficult",
       "points": 4
      }
     ]
    },
    {
     "id": "gooseflesh",
     "label": "Gooseflesh skin",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Skin is smooth",
       "points": 0
      },
      {
       "value": "3",
       "label": "Piloerection can be felt or hairs standing up on arms",
       "points": 3
      },
      {
       "value": "5",
       "label": "Prominent piloerection",
       "points": 5
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Wesson DR, Ling W. The Clinical Opiate Withdrawal Scale (COWS). J Psychoactive Drugs 2003;35:253–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12924748/"
    }
   ]
  },
  {
   "id": "crb-65",
   "name": "CRB-65 Score for Pneumonia (no labs)",
   "short": "CRB-65",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/crb-65/",
   "summary": "CRB-65 is CURB-65 without urea, for use where blood tests are unavailable: Confusion, Respiratory rate ≥30, SBP <90 or DBP ≤60, and age ≥65 (0–4 points). 0 is low risk (home treatment usually appropriate), 1–2 intermediate (consider hospital referral), 3–4 high risk (urgent admission).",
   "formula": "One point each: Confusion · RR ≥30/min · SBP <90 or DBP ≤60 mmHg · Age ≥65",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "confusion",
     "label": "New confusion",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 80
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "dbp",
     "label": "Diastolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 200
    }
   ],
   "references": [
    {
     "title": "Lim WS et al. Defining community acquired pneumonia severity on presentation to hospital. Thorax 2003;58:377–82.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12728155/"
    },
    {
     "title": "Bauer TT et al. CRB-65 predicts death from community-acquired pneumonia. J Intern Med 2006;260:93–101.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16789984/"
    }
   ]
  },
  {
   "id": "cockcroft-gault",
   "name": "Creatinine Clearance (Cockcroft-Gault)",
   "short": "CrCl",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/cockcroft-gault/",
   "summary": "Cockcroft-Gault estimates creatinine clearance as (140 − age) × weight ÷ (72 × serum creatinine), × 0.85 in women. It is still the reference for most renal drug-dosing labels; CrCl <30 mL/min usually triggers major dose reduction.",
   "formula": "CrCl (mL/min) = (140 − age) × weight (kg) ÷ (72 × Scr mg/dL) × 0.85 if female. SI: (140 − age) × weight × 1.23 ÷ Scr (µmol/L) [× 0.85 female]. IBW = 50 kg (M) / 45.5 kg (F) + 0.9055 × (height cm − 152.4). Adjusted BW = IBW + 0.4 × (actual − IBW).",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 25,
     "max": 300
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 120,
     "max": 230,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 1976;16:31–41.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1244564/"
    }
   ]
  },
  {
   "id": "cdai-crohns",
   "name": "Crohn's Disease Activity Index (CDAI)",
   "short": "CDAI",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/cdai-crohns/",
   "summary": "The CDAI (Best 1976) measures Crohn's disease activity from a 7-day diary plus exam, hematocrit and weight. CDAI <150 is remission, 150–219 mild, 220–450 moderate and >450 severe; a fall of ≥100 points (≥70 in some trials) defines response.",
   "formula": "CDAI = 2 × liquid stools (7-day sum) + 5 × abdominal pain (7-day sum, 0–3/day) + 7 × well-being (7-day sum, 0–4/day) + 20 × number of complication categories + 30 × antidiarrheal use + 10 × abdominal mass (0/2/5) + 6 × (expected Hct − Hct; 47 men, 42 women) + 1 × % below standard weight [100 × (1 − weight/standard weight)]",
   "inputs": [
    {
     "id": "stools7",
     "label": "Liquid or very soft stools: total over 7 days",
     "kind": "num",
     "min": 0,
     "max": 300
    },
    {
     "id": "pain7",
     "label": "Abdominal pain ratings summed over 7 days (each day 0 none – 3 severe)",
     "kind": "num",
     "min": 0,
     "max": 21
    },
    {
     "id": "wellbeing7",
     "label": "General well-being ratings summed over 7 days (each day 0 well – 4 terrible)",
     "kind": "num",
     "min": 0,
     "max": 28
    },
    {
     "id": "arthritis",
     "label": "Arthritis or arthralgia",
     "kind": "yn",
     "points": 20,
     "optional": true
    },
    {
     "id": "iritis",
     "label": "Iritis or uveitis",
     "kind": "yn",
     "points": 20,
     "optional": true
    },
    {
     "id": "skinMouth",
     "label": "Erythema nodosum, pyoderma gangrenosum or aphthous stomatitis",
     "kind": "yn",
     "points": 20,
     "optional": true
    },
    {
     "id": "perianal",
     "label": "Anal fissure, fistula or abscess",
     "kind": "yn",
     "points": 20,
     "optional": true
    },
    {
     "id": "otherFistula",
     "label": "Other fistula (e.g. enterocutaneous, enterovesical)",
     "kind": "yn",
     "points": 20,
     "optional": true
    },
    {
     "id": "fever",
     "label": "Fever >37.8 °C during the past week",
     "kind": "yn",
     "points": 20,
     "optional": true
    },
    {
     "id": "antidiarrheal",
     "label": "Taking loperamide/diphenoxylate/opiates for diarrhea",
     "kind": "yn",
     "points": 30,
     "optional": true
    },
    {
     "id": "mass",
     "label": "Abdominal mass",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "questionable",
       "label": "Questionable",
       "points": 2
      },
      {
       "value": "definite",
       "label": "Definite",
       "points": 5
      }
     ]
    },
    {
     "id": "hct",
     "label": "Hematocrit",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 10,
     "max": 70
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 0.3,
     "max": 400
    },
    {
     "id": "stdWeight",
     "label": "Standard (ideal) body weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 20,
     "max": 150
    }
   ],
   "references": [
    {
     "title": "Best WR et al. Development of a Crohn's disease activity index. National Cooperative Crohn's Disease Study. Gastroenterology 1976;70:439–44.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1248701/"
    }
   ]
  },
  {
   "id": "ctsi-balthazar",
   "name": "CT Severity Index (Balthazar) for Acute Pancreatitis",
   "short": "CTSI",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/ctsi-balthazar/",
   "summary": "The CT Severity Index adds the Balthazar grade (A–E, 0–4 points) to the extent of pancreatic necrosis (none 0, ≤30% 2, 30–50% 4, >50% 6) for a 0–10 score: 0–3 mild, 4–6 moderate, 7–10 severe acute pancreatitis.",
   "formula": "CTSI = Balthazar grade (A 0, B 1, C 2, D 3, E 4) + necrosis (none 0, ≤30% 2, 30–50% 4, >50% 6)",
   "inputs": [
    {
     "id": "grade",
     "label": "Balthazar CT grade",
     "kind": "sel",
     "options": [
      {
       "value": "A",
       "label": "A: normal pancreas",
       "points": 0
      },
      {
       "value": "B",
       "label": "B: focal or diffuse enlargement",
       "points": 1
      },
      {
       "value": "C",
       "label": "C: pancreatic inflammation / peripancreatic fat stranding",
       "points": 2
      },
      {
       "value": "D",
       "label": "D: single peripancreatic fluid collection",
       "points": 3
      },
      {
       "value": "E",
       "label": "E: ≥2 collections or retroperitoneal gas",
       "points": 4
      }
     ]
    },
    {
     "id": "necrosis",
     "label": "Pancreatic necrosis",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "le30",
       "label": "≤ 30%",
       "points": 2
      },
      {
       "value": "30to50",
       "label": "30–50%",
       "points": 4
      },
      {
       "value": "gt50",
       "label": "> 50%",
       "points": 6
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Balthazar EJ et al. Acute pancreatitis: value of CT in establishing prognosis. Radiology 1990;174:331–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/2296641/"
    }
   ]
  },
  {
   "id": "curb-65",
   "name": "CURB-65 Score for Pneumonia Severity",
   "short": "CURB-65",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/curb-65/",
   "summary": "CURB-65 scores community-acquired pneumonia severity from Confusion, Urea >7 mmol/L (BUN >19 mg/dL), Respiratory rate ≥30, low Blood pressure (SBP <90 or DBP ≤60) and age ≥65 (0–5 points). 0–1 suggests outpatient care, 2 short admission or supervised outpatient care, and 3–5 severe pneumonia needing hospital (consider ICU at 4–5).",
   "formula": "One point each: Confusion · Urea >7 mmol/L (BUN >19 mg/dL) · RR ≥30/min · SBP <90 or DBP ≤60 mmHg · Age ≥65",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "confusion",
     "label": "New confusion (disorientation to person, place or time)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "bun",
     "label": "BUN (or urea in mmol/L)",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 80
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "dbp",
     "label": "Diastolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 200
    }
   ],
   "references": [
    {
     "title": "Lim WS et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax 2003;58:377–82.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12728155/"
    }
   ]
  },
  {
   "id": "das28-crp",
   "name": "DAS28-CRP (Disease Activity Score, 28 joints, CRP) for Rheumatoid Arthritis",
   "short": "DAS28-CRP",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/das28-crp/",
   "summary": "DAS28-CRP combines 28-joint tender and swollen counts, CRP (mg/L) and the patient global health rating (0–100 mm). The DAS28 thresholds (<2.6 remission, ≤3.2 low, ≤5.1 moderate, >5.1 high) are conventionally applied, although DAS28-CRP runs lower than DAS28-ESR.",
   "formula": "DAS28-CRP = 0.56 × √TJC28 + 0.28 × √SJC28 + 0.36 × ln(CRP mg/L + 1) + 0.014 × patient global health (0–100 mm) + 0.96",
   "inputs": [
    {
     "id": "tjc",
     "label": "Tender joint count (28 joints)",
     "kind": "num",
     "unit": "joints",
     "units": [
      "joints"
     ],
     "min": 0,
     "max": 28
    },
    {
     "id": "sjc",
     "label": "Swollen joint count (28 joints)",
     "kind": "num",
     "unit": "joints",
     "units": [
      "joints"
     ],
     "min": 0,
     "max": 28
    },
    {
     "id": "crp",
     "label": "C-reactive protein",
     "kind": "num",
     "unit": "mg/L",
     "units": [
      "mg/L",
      "mg/dL"
     ],
     "min": 0,
     "max": 500
    },
    {
     "id": "gh",
     "label": "Patient global health (VAS 0–100 mm)",
     "kind": "num",
     "min": 0,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Wells G et al. Validation of the 28-joint Disease Activity Score (DAS28) and EULAR response criteria based on C-reactive protein against disease progression in RA, and comparison with the DAS28 based on ESR. Ann Rheum Dis 2009;68:954–60.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18490431/"
    },
    {
     "title": "Prevoo ML et al. Modified disease activity scores that include twenty-eight-joint counts. Arthritis Rheum 1995;38:44–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/7818570/"
    }
   ]
  },
  {
   "id": "das28-esr",
   "name": "DAS28-ESR (Disease Activity Score, 28 joints, ESR) for Rheumatoid Arthritis",
   "short": "DAS28-ESR",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/das28-esr/",
   "summary": "DAS28-ESR combines 28-joint tender and swollen counts, ESR and the patient global health rating (0–100 mm) into a rheumatoid arthritis activity score. Thresholds: <2.6 remission, ≤3.2 low, >3.2–5.1 moderate, >5.1 high disease activity.",
   "formula": "DAS28-ESR = 0.56 × √TJC28 + 0.28 × √SJC28 + 0.70 × ln(ESR mm/h) + 0.014 × patient global health (0–100 mm)",
   "inputs": [
    {
     "id": "tjc",
     "label": "Tender joint count (28 joints)",
     "kind": "num",
     "unit": "joints",
     "units": [
      "joints"
     ],
     "min": 0,
     "max": 28
    },
    {
     "id": "sjc",
     "label": "Swollen joint count (28 joints)",
     "kind": "num",
     "unit": "joints",
     "units": [
      "joints"
     ],
     "min": 0,
     "max": 28
    },
    {
     "id": "esr",
     "label": "Erythrocyte sedimentation rate (ESR)",
     "kind": "num",
     "unit": "mm/h",
     "units": [
      "mm/h"
     ],
     "min": 1,
     "max": 150
    },
    {
     "id": "gh",
     "label": "Patient global health (VAS 0–100 mm)",
     "kind": "num",
     "min": 0,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Prevoo ML et al. Modified disease activity scores that include twenty-eight-joint counts. Arthritis Rheum 1995;38:44–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/7818570/"
    },
    {
     "title": "Aletaha D, Smolen J. The SDAI and the CDAI: a review of their usefulness and validity in rheumatoid arthritis. Clin Exp Rheumatol 2005;23(5 Suppl 39):S100–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16273793/"
    }
   ]
  },
  {
   "id": "delta-gap",
   "name": "Delta Gap and Delta Ratio",
   "short": "Delta ratio",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/delta-gap/",
   "summary": "The delta ratio (ΔAG ÷ ΔHCO₃, with AG normal 12 and HCO₃ normal 24) detects mixed disorders in a high-anion-gap acidosis: <0.4 normal-gap acidosis, 0.4–0.8 combined high- and normal-gap acidosis, 0.8–2 pure high-gap acidosis, >2 concurrent metabolic alkalosis (or chronic respiratory acidosis).",
   "formula": "Delta ratio = (AG − 12) ÷ (24 − HCO₃⁻). Delta gap = (AG − 12) − (24 − HCO₃⁻). AG = Na⁺ − (Cl⁻ + HCO₃⁻), optionally + 2.5 × (4 − albumin g/dL).",
   "inputs": [
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "cl",
     "label": "Serum chloride",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 60,
     "max": 150
    },
    {
     "id": "hco3",
     "label": "Serum bicarbonate (HCO₃⁻)",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 60
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 6.5,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Rastegar A. Use of the ΔAG/ΔHCO3− ratio in the diagnosis of mixed acid-base disorders. J Am Soc Nephrol 2007;18:2429–31.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/17656477/"
    }
   ]
  },
  {
   "id": "duke-treadmill",
   "name": "Duke Treadmill Score",
   "short": "Duke treadmill",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/duke-treadmill/",
   "summary": "Duke Treadmill Score = exercise time (min, Bruce) − 5 × maximal ST deviation (mm) − 4 × angina index. ≥+5 is low risk (~99% 4-year survival), −10 to +4 moderate (~95%), ≤−11 high (~79%).",
   "formula": "DTS = exercise time (min) − (5 × ST deviation in mm) − (4 × angina index); angina index 0 none, 1 non-limiting, 2 exercise-limiting",
   "inputs": [
    {
     "id": "ex_time",
     "label": "Exercise time (Bruce protocol)",
     "kind": "num",
     "unit": "min",
     "units": [
      "min"
     ],
     "min": 0,
     "max": 30
    },
    {
     "id": "st_dev",
     "label": "Maximal ST deviation (any lead, excluding aVR)",
     "kind": "num",
     "unit": "mm",
     "units": [
      "mm"
     ],
     "min": 0,
     "max": 10
    },
    {
     "id": "angina",
     "label": "Angina during test",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "None",
       "points": 0
      },
      {
       "value": "1",
       "label": "Non-limiting angina",
       "points": 1
      },
      {
       "value": "2",
       "label": "Exercise-limiting angina",
       "points": 2
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Mark DB et al. Prognostic value of a treadmill exercise score in outpatients with suspected coronary artery disease. N Engl J Med 1991;325:849–53.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1875969/"
    },
    {
     "title": "Mark DB et al. Exercise treadmill score for predicting prognosis in coronary artery disease. Ann Intern Med 1987;106:793–800.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3579066/"
    }
   ]
  },
  {
   "id": "ecog-karnofsky",
   "name": "ECOG Performance Status ↔ Karnofsky (KPS) Conversion",
   "short": "ECOG / KPS",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/ecog-karnofsky/",
   "summary": "Converts between ECOG (Zubrod/WHO) performance status 0–5 and the Karnofsky Performance Status 100–0 using the ECOG-ACRIN comparison: KPS 100–90 = ECOG 0, 80–70 = 1, 60–50 = 2, 40–30 = 3, 20–10 = 4, 0 = 5. ECOG 0–1 is the usual eligibility range for most chemotherapy trials.",
   "formula": "ECOG-ACRIN comparison: KPS 100–90 → ECOG 0; 80–70 → 1; 60–50 → 2; 40–30 → 3; 20–10 → 4; 0 → 5.",
   "inputs": [
    {
     "id": "status",
     "label": "Performance status (choose an ECOG grade or a Karnofsky score)",
     "kind": "sel",
     "options": [
      {
       "value": "ecog-0",
       "label": "ECOG 0: Fully active, able to carry on all pre-disease performance without restriction"
      },
      {
       "value": "ecog-1",
       "label": "ECOG 1: Restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature (e.g. light house work, office work)"
      },
      {
       "value": "ecog-2",
       "label": "ECOG 2: Ambulatory and capable of all self-care but unable to carry out any work activities; up and about more than 50% of waking hours"
      },
      {
       "value": "ecog-3",
       "label": "ECOG 3: Capable of only limited self-care; confined to bed or chair more than 50% of waking hours"
      },
      {
       "value": "ecog-4",
       "label": "ECOG 4: Completely disabled; cannot carry on any self-care; totally confined to bed or chair"
      },
      {
       "value": "ecog-5",
       "label": "ECOG 5: Dead"
      },
      {
       "value": "kps-100",
       "label": "KPS 100: Normal, no complaints; no evidence of disease"
      },
      {
       "value": "kps-90",
       "label": "KPS 90: Able to carry on normal activity; minor signs or symptoms of disease"
      },
      {
       "value": "kps-80",
       "label": "KPS 80: Normal activity with effort; some signs or symptoms of disease"
      },
      {
       "value": "kps-70",
       "label": "KPS 70: Cares for self but unable to carry on normal activity or to do active work"
      },
      {
       "value": "kps-60",
       "label": "KPS 60: Requires occasional assistance but is able to care for most personal needs"
      },
      {
       "value": "kps-50",
       "label": "KPS 50: Requires considerable assistance and frequent medical care"
      },
      {
       "value": "kps-40",
       "label": "KPS 40: Disabled; requires special care and assistance"
      },
      {
       "value": "kps-30",
       "label": "KPS 30: Severely disabled; hospitalization is indicated although death not imminent"
      },
      {
       "value": "kps-20",
       "label": "KPS 20: Very ill; hospitalization and active supportive care necessary"
      },
      {
       "value": "kps-10",
       "label": "KPS 10: Moribund"
      },
      {
       "value": "kps-0",
       "label": "KPS 0: Dead"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Oken MM et al. Toxicity and response criteria of the Eastern Cooperative Oncology Group. Am J Clin Oncol 1982;5:649–55.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/7165009/"
    },
    {
     "title": "ECOG-ACRIN Cancer Research Group. ECOG Performance Status Scale.",
     "url": "https://ecog-acrin.org/resources/ecog-performance-status/"
    }
   ]
  },
  {
   "id": "edacs",
   "name": "EDACS (Emergency Department Assessment of Chest Pain Score)",
   "short": "EDACS",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/edacs/",
   "summary": "EDACS scores possible cardiac chest pain from age, sex, risk factors and pain features. EDACS < 16 with no new ischemia on ECG and negative 0 h and 2 h troponins (EDACS-ADP) is low risk for 30-day MACE (sensitivity 99–100%) and suitable for early discharge.",
   "formula": "Age: 18–45 = 2, then +2 per 5-year band (46–50 = 4, 51–55 = 6 … 81–85 = 18, ≥86 = 20) · male +6 · age 18–50 with known CAD or ≥3 risk factors +4 · diaphoresis +3 · radiation to arm/shoulder/neck/jaw +5 · pain with inspiration −4 · pain reproduced by palpation −6",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "cad_rf",
     "label": "Known CAD or ≥3 risk factors (counts only if age 18–50)",
     "kind": "yn",
     "points": 4
    },
    {
     "id": "diaphoresis",
     "label": "Diaphoresis",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "radiation",
     "label": "Pain radiates to arm, shoulder, neck or jaw",
     "kind": "yn",
     "points": 5
    },
    {
     "id": "pleuritic",
     "label": "Pain occurred or worsened with inspiration",
     "kind": "yn",
     "points": -4
    },
    {
     "id": "palpation",
     "label": "Pain reproduced by palpation",
     "kind": "yn",
     "points": -6
    }
   ],
   "references": [
    {
     "title": "Than M et al. Development and validation of the Emergency Department Assessment of Chest pain Score and 2 h accelerated diagnostic protocol. Emerg Med Australas 2014;26:34–44.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/24428678/"
    }
   ]
  },
  {
   "id": "epds",
   "name": "Edinburgh Postnatal Depression Scale (EPDS)",
   "short": "EPDS",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/epds/",
   "summary": "The EPDS is a 10-item self-report screen for perinatal depression scored 0–30 over the past 7 days. A score ≥10 suggests possible depression and ≥13 probable depression; any positive answer to item 10 (thoughts of self-harm) needs immediate assessment.",
   "formula": "Ten items scored 0–3. Items 1, 2 and 4 score 0→3 in printed order; items 3 and 5–10 are reverse-scored (3→0). Range 0–30.",
   "inputs": [
    {
     "id": "q1",
     "label": "I have been able to laugh and see the funny side of things",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "As much as I always could",
       "points": 0
      },
      {
       "value": "1",
       "label": "Not quite so much now",
       "points": 1
      },
      {
       "value": "2",
       "label": "Definitely not so much now",
       "points": 2
      },
      {
       "value": "3",
       "label": "Not at all",
       "points": 3
      }
     ]
    },
    {
     "id": "q2",
     "label": "I have looked forward with enjoyment to things",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "As much as I ever did",
       "points": 0
      },
      {
       "value": "1",
       "label": "Rather less than I used to",
       "points": 1
      },
      {
       "value": "2",
       "label": "Definitely less than I used to",
       "points": 2
      },
      {
       "value": "3",
       "label": "Hardly at all",
       "points": 3
      }
     ]
    },
    {
     "id": "q3",
     "label": "I have blamed myself unnecessarily when things went wrong",
     "kind": "sel",
     "options": [
      {
       "value": "3",
       "label": "Yes, most of the time",
       "points": 3
      },
      {
       "value": "2",
       "label": "Yes, some of the time",
       "points": 2
      },
      {
       "value": "1",
       "label": "Not very often",
       "points": 1
      },
      {
       "value": "0",
       "label": "No, never",
       "points": 0
      }
     ]
    },
    {
     "id": "q4",
     "label": "I have been anxious or worried for no good reason",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No, not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Hardly ever",
       "points": 1
      },
      {
       "value": "2",
       "label": "Yes, sometimes",
       "points": 2
      },
      {
       "value": "3",
       "label": "Yes, very often",
       "points": 3
      }
     ]
    },
    {
     "id": "q5",
     "label": "I have felt scared or panicky for no very good reason",
     "kind": "sel",
     "options": [
      {
       "value": "3",
       "label": "Yes, quite a lot",
       "points": 3
      },
      {
       "value": "2",
       "label": "Yes, sometimes",
       "points": 2
      },
      {
       "value": "1",
       "label": "No, not much",
       "points": 1
      },
      {
       "value": "0",
       "label": "No, not at all",
       "points": 0
      }
     ]
    },
    {
     "id": "q6",
     "label": "Things have been getting on top of me",
     "kind": "sel",
     "options": [
      {
       "value": "3",
       "label": "Yes, most of the time I haven't been able to cope at all",
       "points": 3
      },
      {
       "value": "2",
       "label": "Yes, sometimes I haven't been coping as well as usual",
       "points": 2
      },
      {
       "value": "1",
       "label": "No, most of the time I have coped quite well",
       "points": 1
      },
      {
       "value": "0",
       "label": "No, I have been coping as well as ever",
       "points": 0
      }
     ]
    },
    {
     "id": "q7",
     "label": "I have been so unhappy that I have had difficulty sleeping",
     "kind": "sel",
     "options": [
      {
       "value": "3",
       "label": "Yes, most of the time",
       "points": 3
      },
      {
       "value": "2",
       "label": "Yes, sometimes",
       "points": 2
      },
      {
       "value": "1",
       "label": "Not very often",
       "points": 1
      },
      {
       "value": "0",
       "label": "No, not at all",
       "points": 0
      }
     ]
    },
    {
     "id": "q8",
     "label": "I have felt sad or miserable",
     "kind": "sel",
     "options": [
      {
       "value": "3",
       "label": "Yes, most of the time",
       "points": 3
      },
      {
       "value": "2",
       "label": "Yes, quite often",
       "points": 2
      },
      {
       "value": "1",
       "label": "Not very often",
       "points": 1
      },
      {
       "value": "0",
       "label": "No, not at all",
       "points": 0
      }
     ]
    },
    {
     "id": "q9",
     "label": "I have been so unhappy that I have been crying",
     "kind": "sel",
     "options": [
      {
       "value": "3",
       "label": "Yes, most of the time",
       "points": 3
      },
      {
       "value": "2",
       "label": "Yes, quite often",
       "points": 2
      },
      {
       "value": "1",
       "label": "Only occasionally",
       "points": 1
      },
      {
       "value": "0",
       "label": "No, never",
       "points": 0
      }
     ]
    },
    {
     "id": "q10",
     "label": "The thought of harming myself has occurred to me",
     "kind": "sel",
     "options": [
      {
       "value": "3",
       "label": "Yes, quite often",
       "points": 3
      },
      {
       "value": "2",
       "label": "Sometimes",
       "points": 2
      },
      {
       "value": "1",
       "label": "Hardly ever",
       "points": 1
      },
      {
       "value": "0",
       "label": "Never",
       "points": 0
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Cox JL, Holden JM, Sagovsky R. Detection of postnatal depression: development of the 10-item Edinburgh Postnatal Depression Scale. Br J Psychiatry 1987;150:782–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3651732/"
    }
   ]
  },
  {
   "id": "egfr-ckd-epi-2021-cys",
   "name": "eGFR (CKD-EPI 2021 Creatinine–Cystatin C)",
   "short": "eGFRcr-cys",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/egfr-ckd-epi-2021-cys/",
   "summary": "The race-free 2021 CKD-EPI creatinine–cystatin C equation combines both markers and is the most accurate routine eGFR; KDIGO recommends it to confirm CKD when creatinine-based eGFR is near a decision threshold or muscle mass is atypical. Normal is ≥90 mL/min/1.73 m².",
   "formula": "eGFR = 135 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−0.544 × min(Scys/0.8, 1)^−0.323 × max(Scys/0.8, 1)^−0.778 × 0.9961^age × 0.963 [if female]; κ = 0.7 (F) / 0.9 (M); α = −0.219 (F) / −0.144 (M). Scr in mg/dL, Scys in mg/L.",
   "inputs": [
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "cys",
     "label": "Serum cystatin C",
     "kind": "num",
     "min": 0.2,
     "max": 10
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Inker LA et al. New creatinine- and cystatin C–based equations to estimate GFR without race. N Engl J Med 2021;385:1737–49.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/34554658/"
    },
    {
     "title": "KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD. Kidney Int 2024;105(4S):S117–S314.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/38490803/"
    }
   ]
  },
  {
   "id": "egfr-ckd-epi-2021",
   "name": "eGFR (CKD-EPI 2021, race-free)",
   "short": "eGFR",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/egfr-ckd-epi-2021/",
   "summary": "Estimates glomerular filtration rate from serum creatinine, age and sex using the race-free 2021 CKD-EPI creatinine equation, the current recommended equation in North America. Normal is ≥90 mL/min/1.73 m².",
   "formula": "eGFR = 142 × min(Scr/κ, 1)^α × max(Scr/κ, 1)^−1.200 × 0.9938^age × 1.012 [if female]; κ = 0.7 (F) / 0.9 (M); α = −0.241 (F) / −0.302 (M)",
   "inputs": [
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Inker LA et al. New creatinine- and cystatin C–based equations to estimate GFR without race. N Engl J Med 2021;385:1737–49.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/34554658/"
    }
   ]
  },
  {
   "id": "egfr-mdrd",
   "name": "eGFR (MDRD Study equation)",
   "short": "MDRD eGFR",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/egfr-mdrd/",
   "summary": "The 4-variable IDMS-traceable MDRD equation, 175 × Scr^−1.154 × age^−0.203 (× 0.742 female), estimates GFR in mL/min/1.73 m². It has been superseded by CKD-EPI 2021 and underestimates GFR above 60.",
   "formula": "eGFR = 175 × Scr (mg/dL)^−1.154 × age^−0.203 × 0.742 [if female] × 1.212 [if Black, original equation]",
   "inputs": [
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "black",
     "label": "Black race (original race coefficient ×1.212)",
     "kind": "yn",
     "points": 0,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Levey AS et al. Using standardized serum creatinine values in the MDRD Study equation for estimating GFR. Ann Intern Med 2006;145:247–54.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16908915/"
    }
   ]
  },
  {
   "id": "estimated-conception-date",
   "name": "Estimated Conception Date from LMP",
   "short": "Conception date",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/estimated-conception-date/",
   "summary": "Estimated conception (ovulation) date = first day of the last menstrual period + 14 days, adjusted by (cycle length − 28) days. It is an estimate: fertilisation can occur up to about 5 days after intercourse.",
   "formula": "Conception ≈ LMP + 14 days + (cycle length − 28) days",
   "inputs": [
    {
     "id": "lmp",
     "label": "First day of last menstrual period (LMP)",
     "kind": "date"
    },
    {
     "id": "cycle",
     "label": "Usual cycle length",
     "kind": "num",
     "min": 20,
     "max": 45,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "ACOG Committee Opinion No 700: Methods for Estimating the Due Date. Obstet Gynecol 2017;129:e150–4.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/28426621/"
    },
    {
     "title": "MedCalc-Bench reference implementation (estimated_conception_date.py).",
     "url": "https://github.com/ncbi-nlp/MedCalc-Bench/tree/main/calculator_implementations"
    }
   ]
  },
  {
   "id": "respiratory-compensation",
   "name": "Expected HCO3 in Respiratory Acidosis / Alkalosis",
   "short": "Resp compensation",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/respiratory-compensation/",
   "summary": "Expected HCO₃ for a primary respiratory disorder per 10 mmHg change in pCO₂ from 40: acute acidosis +1, chronic acidosis +3.5, acute alkalosis −2, chronic alkalosis −4 mmol/L. A measured HCO₃ outside ±2 suggests an additional metabolic disorder.",
   "formula": "Expected HCO₃⁻ = 24 + k × (pCO₂ − 40); k = 0.1 (acute acidosis), 0.35 (chronic acidosis), 0.2 (acute alkalosis), 0.4 (chronic alkalosis). Range ± 2 mmol/L.",
   "inputs": [
    {
     "id": "pco2",
     "label": "Arterial pCO₂",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 5,
     "max": 150
    },
    {
     "id": "chronicity",
     "label": "Duration",
     "kind": "sel",
     "options": [
      {
       "value": "acute",
       "label": "Acute (< 24–48 h)"
      },
      {
       "value": "chronic",
       "label": "Chronic (> 3–5 days)"
      }
     ]
    },
    {
     "id": "hco3",
     "label": "Measured HCO₃⁻ (optional)",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 60,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Berend K, de Vries APJ, Gans ROB. Physiological approach to assessment of acid–base disturbances. N Engl J Med 2014;371:1434–45.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/25295502/"
    }
   ]
  },
  {
   "id": "expected-pco2-metabolic-alkalosis",
   "name": "Expected pCO2 in Metabolic Alkalosis",
   "short": "pCO2 in met alk",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/expected-pco2-metabolic-alkalosis/",
   "summary": "In metabolic alkalosis pCO₂ rises about 0.7 mmHg per 1 mmol/L rise in HCO₃: expected pCO₂ ≈ 40 + 0.7 × (HCO₃ − 24) ± 5 mmHg. Compensation rarely pushes pCO₂ above about 55 mmHg.",
   "formula": "Expected pCO₂ (mmHg) = 40 + 0.7 × (HCO₃⁻ − 24) ± 5 (≈ 0.7 × HCO₃⁻ + 23). Upper limit of compensation ≈ 55 mmHg.",
   "inputs": [
    {
     "id": "hco3",
     "label": "Serum bicarbonate (HCO₃⁻)",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 24,
     "max": 60
    },
    {
     "id": "pco2",
     "label": "Measured pCO₂ (optional)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 5,
     "max": 150,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Berend K, de Vries APJ, Gans ROB. Physiological approach to assessment of acid–base disturbances. N Engl J Med 2014;371:1434–45.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/25295502/"
    },
    {
     "title": "Merck Manual Professional. Primary changes and compensations in simple acid-base disorders (table).",
     "url": "https://www.merckmanuals.com/professional/multimedia/table/primary-changes-and-compensations-in-simple-acid-base-disorders"
    }
   ]
  },
  {
   "id": "feverpain",
   "name": "FeverPAIN Score for Streptococcal Pharyngitis",
   "short": "FeverPAIN",
   "category": "Infectious Disease",
   "url": "https://askcalc.site/calc/feverpain/",
   "summary": "FeverPAIN scores 1 point each for Fever in the past 24 h, Purulence, Attending rapidly (≤3 days), severely Inflamed tonsils and No cough or coryza (0–5). 0–1: no antibiotic; 2–3: consider no or delayed antibiotic; 4–5: immediate or delayed antibiotic (NICE NG84).",
   "formula": "Fever (24 h) 1 · Purulence 1 · Attend rapidly ≤3 days 1 · severely Inflamed tonsils 1 · No cough/coryza 1",
   "inputs": [
    {
     "id": "fever",
     "label": "Fever in past 24 hours",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "purulence",
     "label": "Purulence (pharyngeal/tonsillar exudate)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "rapid",
     "label": "Attended rapidly (symptom onset ≤3 days)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "inflamed",
     "label": "Severely inflamed tonsils",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "nocough",
     "label": "No cough or coryza",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Little P et al. Clinical score and rapid antigen detection test to guide antibiotic use for sore throats: randomised controlled trial of PRISM. BMJ 2013;347:f5806.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/24114306/"
    },
    {
     "title": "MedCalc-Bench reference implementation (feverpain.py).",
     "url": "https://github.com/ncbi-nlp/MedCalc-Bench/tree/main/calculator_implementations"
    }
   ]
  },
  {
   "id": "fib-4",
   "name": "FIB-4 Index for Liver Fibrosis",
   "short": "FIB-4",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/fib-4/",
   "summary": "FIB-4 = (age × AST) ÷ (platelets × √ALT) estimates advanced liver fibrosis. In MASLD/NAFLD, <1.3 makes advanced fibrosis unlikely, 1.3–2.67 is indeterminate (needs elastography) and >2.67 indicates high risk; for age ≥65 the low cut-off is 2.0.",
   "formula": "FIB-4 = age (years) × AST (U/L) ÷ [platelets (10⁹/L) × √ALT (U/L)]",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "ast",
     "label": "AST",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 1,
     "max": 20000
    },
    {
     "id": "alt",
     "label": "ALT",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 1,
     "max": 20000
    },
    {
     "id": "plt",
     "label": "Platelet count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 1,
     "max": 2000
    }
   ],
   "references": [
    {
     "title": "Sterling RK et al. Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection. Hepatology 2006;43:1317–25.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16729309/"
    },
    {
     "title": "Shah AG et al. Comparison of noninvasive markers of fibrosis in patients with nonalcoholic fatty liver disease. Clin Gastroenterol Hepatol 2009;7:1104–12.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/19523535/"
    },
    {
     "title": "McPherson S et al. Age as a confounding factor for the accurate non-invasive diagnosis of advanced NAFLD fibrosis. Am J Gastroenterol 2017;112:740–51.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/27725647/"
    }
   ]
  },
  {
   "id": "findrisc",
   "name": "FINDRISC (Finnish Diabetes Risk Score)",
   "short": "FINDRISC",
   "category": "Endocrine & Metabolic",
   "url": "https://askcalc.site/calc/findrisc/",
   "summary": "FINDRISC (0–26) estimates 10-year risk of type 2 diabetes from age, BMI, waist, activity, diet, antihypertensives, prior high glucose and family history. <7 low (~1%), 7–11 slightly elevated (~4%), 12–14 moderate (~17%), 15–20 high (~33%), >20 very high (~50%); ≥12 (or ≥15) warrants glucose testing.",
   "formula": "Age <45 0 · 45–54 2 · 55–64 3 · ≥65 4. BMI <25 0 · 25–30 1 · >30 3. Waist men <94 0 · 94–102 3 · >102 4 (women <80 / 80–88 / >88). No daily 30-min activity 2. Not daily vegetables/fruit 1. Antihypertensive drugs 2. History of high glucose 5. Family history: second-degree 3, first-degree 5.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "bmi",
     "label": "Body mass index",
     "kind": "num",
     "min": 10,
     "max": 100
    },
    {
     "id": "waist",
     "label": "Waist circumference",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "in"
     ],
     "min": 40,
     "max": 250
    },
    {
     "id": "active",
     "label": "At least 30 minutes of physical activity daily (work or leisure)",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "veg",
     "label": "Eats vegetables, fruit or berries every day",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "bp_meds",
     "label": "Ever regularly taken antihypertensive medication",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "high_glucose",
     "label": "Ever found to have high blood glucose (check-up, illness, pregnancy)",
     "kind": "yn",
     "points": 5
    },
    {
     "id": "family",
     "label": "Family history of diabetes",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "No",
       "points": 0
      },
      {
       "value": "second",
       "label": "Yes: grandparent, aunt, uncle or first cousin",
       "points": 3
      },
      {
       "value": "first",
       "label": "Yes: parent, sibling or child",
       "points": 5
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Lindström J, Tuomilehto J. The diabetes risk score: a practical tool to predict type 2 diabetes risk. Diabetes Care 2003;26:725–31.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12610029/"
    },
    {
     "title": "Saaristo T et al. Cross-sectional evaluation of the Finnish Diabetes Risk Score. Diab Vasc Dis Res 2005;2:67–72.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16305061/"
    }
   ]
  },
  {
   "id": "fena",
   "name": "Fractional Excretion of Sodium (FENa)",
   "short": "FENa",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/fena/",
   "summary": "FENa = (urine Na × plasma creatinine) ÷ (plasma Na × urine creatinine) × 100. In oliguric AKI, FENa <1% suggests a prerenal cause and >2% suggests acute tubular necrosis; diuretics invalidate it (use FEUrea).",
   "formula": "FENa (%) = (U_Na × P_Cr) ÷ (P_Na × U_Cr) × 100 (creatinine in the same units for plasma and urine).",
   "inputs": [
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "una",
     "label": "Urine sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 400
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "ucreat",
     "label": "Urine creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L",
      "mmol/L"
     ],
     "min": 1,
     "max": 1000
    }
   ],
   "references": [
    {
     "title": "Espinel CH. The FENa test: use in the differential diagnosis of acute renal failure. JAMA 1976;236:579–81.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/947239/"
    }
   ]
  },
  {
   "id": "feurea",
   "name": "Fractional Excretion of Urea (FEUrea)",
   "short": "FEUrea",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/feurea/",
   "summary": "FEUrea = (urine urea × plasma creatinine) ÷ (plasma urea × urine creatinine) × 100. FEUrea ≤35% suggests prerenal AKI and >50% suggests ATN; unlike FENa it remains useful after diuretics.",
   "formula": "FEUrea (%) = (U_urea × P_Cr) ÷ (P_urea × U_Cr) × 100 (urea and creatinine each in matching units for plasma and urine).",
   "inputs": [
    {
     "id": "bun",
     "label": "BUN / serum urea",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "uurea",
     "label": "Urine urea (UUN)",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 10,
     "max": 5000
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "ucreat",
     "label": "Urine creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L",
      "mmol/L"
     ],
     "min": 1,
     "max": 1000
    }
   ],
   "references": [
    {
     "title": "Carvounis CP, Nisar S, Guro-Razuman S. Significance of the fractional excretion of urea in the differential diagnosis of acute renal failure. Kidney Int 2002;62:2223–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12427149/"
    }
   ]
  },
  {
   "id": "framingham-risk-score",
   "name": "Framingham Risk Score (ATP III, 10-Year Hard CHD)",
   "short": "Framingham (ATP III)",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/framingham-risk-score/",
   "summary": "The ATP III Framingham equation estimates 10-year risk of hard coronary heart disease (MI or coronary death) in adults 30–79 without diabetes or CHD, from age, sex, total and HDL cholesterol, systolic BP, BP treatment and smoking. <10% low, 10–20% intermediate, >20% high (CHD risk equivalent).",
   "formula": "Risk = 1 − S₀^exp(Σβx). Men (S₀ 0.9402): 52.00961·ln(age) + 20.014077·ln(TC) − 0.905964·ln(HDL) + 1.305784·ln(SBP) + 0.241549·BPtx + 12.096316·smoker − 4.605038·ln(age)·ln(TC) − 2.84367·ln(age*)·smoker − 2.93323·ln(age)² − 172.300168. Women (S₀ 0.98767): 31.764001·ln(age) + 22.465206·ln(TC) − 1.187731·ln(HDL) + 2.552905·ln(SBP) + 0.420251·BPtx + 13.07543·smoker − 5.060998·ln(age)·ln(TC) − 2.996945·ln(age*)·smoker − 146.5933061. age* = age capped at 70 (men) or 78 (women); TC, HDL in mg/dL.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 30,
     "max": 79
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "tc",
     "label": "Total cholesterol",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 100,
     "max": 500
    },
    {
     "id": "hdl",
     "label": "HDL cholesterol",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 10,
     "max": 150
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 70,
     "max": 250
    },
    {
     "id": "bptx",
     "label": "On blood-pressure medication",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "smoker",
     "label": "Current smoker",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "NCEP Expert Panel. Third Report of the NCEP Adult Treatment Panel III (ATP III) final report. Circulation 2002;106:3143–421.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12485966/"
    },
    {
     "title": "Wilson PW et al. Prediction of coronary heart disease using risk factor categories. Circulation 1998;97:1837–47.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9603539/"
    },
    {
     "title": "MedCalc-Bench reference implementation (framingham_risk_score.py).",
     "url": "https://github.com/ncbi-nlp/MedCalc-Bench/tree/main/calculator_implementations"
    }
   ]
  },
  {
   "id": "free-water-deficit",
   "name": "Free Water Deficit in Hypernatremia",
   "short": "Free water deficit",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/free-water-deficit/",
   "summary": "Free water deficit = total body water × (Na/140 − 1), with TBW = 0.6 × weight (men), 0.5 (women, older men), 0.45 (older women). Correct chronic hypernatraemia by no more than about 10 mmol/L per 24 h, and add ongoing losses.",
   "formula": "FWD (L) = TBW × (Na⁺/140 − 1). TBW = weight × 0.6 (children and men <65), 0.5 (women <65, men ≥65), 0.45 (women ≥65).",
   "inputs": [
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Adrogué HJ, Madias NE. Hypernatremia. N Engl J Med 2000;342:1493–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10816188/"
    }
   ]
  },
  {
   "id": "gad-7",
   "name": "GAD-7 Generalized Anxiety Disorder Scale",
   "short": "GAD-7",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/gad-7/",
   "summary": "The GAD-7 rates seven anxiety symptoms from 0 to 3 over the last 2 weeks, total 0–21. Scores of 5, 10 and 15 mark mild, moderate and severe anxiety; ≥10 identifies probable generalized anxiety disorder (sensitivity 89%, specificity 82%).",
   "formula": "Sum of 7 items, each 0 (not at all) to 3 (nearly every day) over the past 2 weeks. Range 0–21.",
   "inputs": [
    {
     "id": "q1",
     "label": "Feeling nervous, anxious, or on edge",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q2",
     "label": "Not being able to stop or control worrying",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q3",
     "label": "Worrying too much about different things",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q4",
     "label": "Trouble relaxing",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q5",
     "label": "Being so restless that it is hard to sit still",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q6",
     "label": "Becoming easily annoyed or irritable",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q7",
     "label": "Feeling afraid, as if something awful might happen",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Spitzer RL, Kroenke K, Williams JBW, Löwe B. A brief measure for assessing generalized anxiety disorder: the GAD-7. Arch Intern Med 2006;166:1092–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16717171/"
    }
   ]
  },
  {
   "id": "gestational-age-from-edd",
   "name": "Gestational Age from Due Date",
   "short": "GA from EDD",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/gestational-age-from-edd/",
   "summary": "Gestational age on a given date equals 280 days minus the days remaining until the estimated due date (EDD), expressed in completed weeks and days. Term is 37w0d–41w6d.",
   "formula": "GA (days) = 280 − (EDD − date)   ·   weeks = ⌊GA ÷ 7⌋, days = GA mod 7",
   "inputs": [
    {
     "id": "edd",
     "label": "Estimated due date (EDD)",
     "kind": "date"
    },
    {
     "id": "asOf",
     "label": "Date to calculate GA on",
     "kind": "date"
    }
   ],
   "references": [
    {
     "title": "ACOG Committee Opinion No 700: Methods for Estimating the Due Date. Obstet Gynecol 2017;129:e150–4.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/28426621/"
    }
   ]
  },
  {
   "id": "gahs",
   "name": "Glasgow Alcoholic Hepatitis Score (GAHS)",
   "short": "GAHS",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/gahs/",
   "summary": "The Glasgow Alcoholic Hepatitis Score (5–12) uses age, white cell count, urea, PT ratio/INR and bilirubin to predict mortality in alcohol-associated hepatitis. A score ≥9 predicts poor survival and identifies patients who may benefit from corticosteroids.",
   "formula": "Age <50 = 1, ≥50 = 2 · WCC <15 = 1, ≥15 ×10⁹/L = 2 · Urea <5 = 1, ≥5 mmol/L (BUN ≥14 mg/dL) = 2 · PT ratio/INR <1.5 = 1, 1.5–2.0 = 2, >2.0 = 3 · Bilirubin <125 = 1, 125–250 = 2, >250 µmol/L (7.3 / 14.6 mg/dL) = 3",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "wbc",
     "label": "White blood cell count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0.1,
     "max": 300
    },
    {
     "id": "bun",
     "label": "Urea (or BUN)",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "inr",
     "label": "PT ratio or INR",
     "kind": "num",
     "min": 0.5,
     "max": 20
    },
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    }
   ],
   "references": [
    {
     "title": "Forrest EH et al. Analysis of factors predictive of mortality in alcoholic hepatitis and derivation and validation of the Glasgow alcoholic hepatitis score. Gut 2005;54:1174–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16009691/"
    }
   ]
  },
  {
   "id": "gcs",
   "name": "Glasgow Coma Scale (GCS)",
   "short": "GCS",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/gcs/",
   "summary": "The Glasgow Coma Scale sums eye opening (1–4), verbal response (1–5) and motor response (1–6) for a total of 3–15. Head injury severity: 13–15 mild, 9–12 moderate, ≤8 severe (consider airway protection).",
   "formula": "GCS = Eye (1–4) + Verbal (1–5) + Motor (1–6); range 3–15",
   "inputs": [
    {
     "id": "eye",
     "label": "Eye opening",
     "kind": "sel",
     "options": [
      {
       "value": "4",
       "label": "Spontaneous (4)",
       "points": 4
      },
      {
       "value": "3",
       "label": "To sound / voice (3)",
       "points": 3
      },
      {
       "value": "2",
       "label": "To pressure / pain (2)",
       "points": 2
      },
      {
       "value": "1",
       "label": "None (1)",
       "points": 1
      }
     ]
    },
    {
     "id": "verbal",
     "label": "Verbal response",
     "kind": "sel",
     "options": [
      {
       "value": "5",
       "label": "Oriented (5)",
       "points": 5
      },
      {
       "value": "4",
       "label": "Confused (4)",
       "points": 4
      },
      {
       "value": "3",
       "label": "Inappropriate words (3)",
       "points": 3
      },
      {
       "value": "2",
       "label": "Incomprehensible sounds (2)",
       "points": 2
      },
      {
       "value": "1",
       "label": "None (1)",
       "points": 1
      }
     ]
    },
    {
     "id": "motor",
     "label": "Motor response",
     "kind": "sel",
     "options": [
      {
       "value": "6",
       "label": "Obeys commands (6)",
       "points": 6
      },
      {
       "value": "5",
       "label": "Localizes to pain (5)",
       "points": 5
      },
      {
       "value": "4",
       "label": "Normal flexion / withdraws (4)",
       "points": 4
      },
      {
       "value": "3",
       "label": "Abnormal flexion / decorticate (3)",
       "points": 3
      },
      {
       "value": "2",
       "label": "Extension / decerebrate (2)",
       "points": 2
      },
      {
       "value": "1",
       "label": "None (1)",
       "points": 1
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Teasdale G, Jennett B. Assessment of coma and impaired consciousness: a practical scale. Lancet 1974;2:81–4.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4136544/"
    }
   ]
  },
  {
   "id": "glasgow-blatchford",
   "name": "Glasgow-Blatchford Bleeding Score (GBS)",
   "short": "Glasgow-Blatchford",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/glasgow-blatchford/",
   "summary": "The Glasgow-Blatchford score (0–23) predicts need for transfusion, endoscopic therapy or surgery in upper GI bleeding using urea, hemoglobin, systolic BP, pulse and clinical features. A score of 0–1 identifies very-low-risk patients suitable for outpatient management (ACG 2021).",
   "formula": "Urea (mmol/L) 6.5–<8 = 2, 8–<10 = 3, 10–<25 = 4, ≥25 = 6 · Hb men 12–<13 = 1, 10–<12 = 3, <10 = 6; women 10–<12 = 1, <10 = 6 · SBP 100–109 = 1, 90–99 = 2, <90 = 3 · Pulse ≥100 = 1 · Melena 1 · Syncope 2 · Hepatic disease 2 · Cardiac failure 2. (BUN mg/dL = urea mmol/L × 2.8)",
   "inputs": [
    {
     "id": "bun",
     "label": "Blood urea (or BUN)",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "hgb",
     "label": "Hemoglobin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 2,
     "max": 25
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 250
    },
    {
     "id": "melena",
     "label": "Melena",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "syncope",
     "label": "Presented with syncope",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "liver",
     "label": "Hepatic disease (known history or clinical/lab evidence)",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "hf",
     "label": "Cardiac failure (known history or clinical/echo evidence)",
     "kind": "yn",
     "points": 2
    }
   ],
   "references": [
    {
     "title": "Blatchford O et al. A risk score to predict need for treatment for upper-gastrointestinal haemorrhage. Lancet 2000;356:1318–21.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11073021/"
    },
    {
     "title": "Laine L et al. ACG Clinical Guideline: upper gastrointestinal and ulcer bleeding. Am J Gastroenterol 2021;116:899–917.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/33929377/"
    }
   ]
  },
  {
   "id": "glasgow-imrie",
   "name": "Glasgow-Imrie Criteria for Acute Pancreatitis Severity",
   "short": "Glasgow-Imrie",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/glasgow-imrie/",
   "summary": "The modified Glasgow (Imrie) score counts 8 laboratory criteria within 48 hours of admission for acute pancreatitis (PaO₂ <60 mmHg, age >55, WBC >15, Ca <8 mg/dL, BUN >45 mg/dL, LDH >600, albumin <3.2 g/dL, glucose >180 mg/dL). A score ≥3 predicts severe pancreatitis.",
   "formula": "One point each (worst value within 48 h): PaO₂ <8 kPa (60 mmHg); age >55; WBC >15 ×10⁹/L; Ca <2.0 mmol/L; urea >16 mmol/L (BUN >45 mg/dL); LDH >600 U/L; albumin <32 g/L; glucose >10 mmol/L",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "wbc",
     "label": "White cell count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 200
    },
    {
     "id": "glucose",
     "label": "Glucose",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 10,
     "max": 3000
    },
    {
     "id": "bun",
     "label": "BUN / serum urea",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "pao2",
     "label": "PaO₂",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 20,
     "max": 700
    },
    {
     "id": "calcium",
     "label": "Serum calcium",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 2,
     "max": 20
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 6.5
    },
    {
     "id": "ldh",
     "label": "LDH",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 10,
     "max": 20000
    }
   ],
   "references": [
    {
     "title": "Blamey SL et al. Prognostic factors in acute pancreatitis. Gut 1984;25:1340–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/6510766/"
    }
   ]
  },
  {
   "id": "grace-acs",
   "name": "GRACE Score for In-Hospital Mortality in ACS",
   "short": "GRACE",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/grace-acs/",
   "summary": "The GRACE score (Granger 2003) estimates in-hospital mortality across the ACS spectrum from age, heart rate, SBP, creatinine, Killip class, cardiac arrest, ST deviation and cardiac enzymes. For NSTE-ACS, ≤108 is low (<1%), 109–140 intermediate (1–3%), >140 high (>3%) risk.",
   "formula": "Points: Killip (I 0, II 20, III 39, IV 59) · SBP (< 80: 58, 80–99: 53, 100–119: 43, 120–139: 34, 140–159: 24, 160–199: 10, ≥ 200: 0) · HR (< 50: 0, 50–69: 3, 70–89: 9, 90–109: 15, 110–149: 24, 150–199: 38, ≥ 200: 46) · Age (< 30: 0, 30–39: 8, 40–49: 25, 50–59: 41, 60–69: 58, 70–79: 75, 80–89: 91, ≥ 90: 100) · Creatinine mg/dL (< 0.4: 1, 0.4–0.79: 4, 0.8–1.19: 7, 1.2–1.59: 10, 1.6–1.99: 13, 2.0–3.99: 21, ≥ 4: 28) · cardiac arrest 39 · ST deviation 28 · elevated enzymes 14. Mortality from the published nomogram (points 60→0.2%, 70→0.3, 80→0.4, 90→0.6, 100→0.8, 110→1.1, 120→1.6, 130→2.1, 140→2.9, 150→3.9, 160→5.4, 170→7.3, 180→9.8, 190→13, 200→18, 210→23, 220→29, 230→36, 240→44, 250→52), linearly interpolated between 10-point steps.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 300
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "killip",
     "label": "Killip class",
     "kind": "sel",
     "options": [
      {
       "value": "I",
       "label": "I: no heart failure",
       "points": 0
      },
      {
       "value": "II",
       "label": "II: rales/crackles, S3 or JVP raised",
       "points": 20
      },
      {
       "value": "III",
       "label": "III: pulmonary edema",
       "points": 39
      },
      {
       "value": "IV",
       "label": "IV: cardiogenic shock",
       "points": 59
      }
     ]
    },
    {
     "id": "arrest",
     "label": "Cardiac arrest at admission",
     "kind": "yn",
     "points": 39
    },
    {
     "id": "st",
     "label": "ST-segment deviation",
     "kind": "yn",
     "points": 28
    },
    {
     "id": "enzymes",
     "label": "Elevated cardiac enzymes/markers",
     "kind": "yn",
     "points": 14
    }
   ],
   "references": [
    {
     "title": "Granger CB et al. Predictors of hospital mortality in the Global Registry of Acute Coronary Events. Arch Intern Med 2003;163:2345–53.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/14581255/"
    }
   ]
  },
  {
   "id": "h2fpef",
   "name": "H2FPEF Score for HFpEF Probability",
   "short": "H2FPEF",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/h2fpef/",
   "summary": "H₂FPEF (0–9) estimates the probability of heart failure with preserved ejection fraction in unexplained dyspnea: Heavy (BMI >30) 2, Hypertensive (≥2 drugs) 1, AF 3, Pulmonary hypertension (PASP >35) 1, Elder (>60) 1, Filling pressure (E/e′ >9) 1. 0–1 low, 2–5 intermediate (further testing), 6–9 high probability.",
   "formula": "H: BMI > 30 kg/m² 2 · H: ≥ 2 antihypertensive drugs 1 · F: atrial fibrillation 3 · P: PASP > 35 mmHg 1 · E: age > 60 1 · F: E/e′ > 9 1",
   "inputs": [
    {
     "id": "bmi",
     "label": "Body mass index",
     "kind": "num",
     "unit": "kg/m²",
     "units": [
      "kg/m²"
     ],
     "min": 10,
     "max": 90
    },
    {
     "id": "bp_meds",
     "label": "Number of antihypertensive medications",
     "kind": "num",
     "unit": "drugs",
     "units": [
      "drugs"
     ],
     "min": 0,
     "max": 10
    },
    {
     "id": "af",
     "label": "Atrial fibrillation (paroxysmal or persistent)",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "pasp",
     "label": "Pulmonary artery systolic pressure (echo)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 5,
     "max": 150
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "e_eprime",
     "label": "E/e′ ratio (echo)",
     "kind": "num",
     "unit": "ratio",
     "units": [
      "ratio"
     ],
     "min": 1,
     "max": 50
    }
   ],
   "references": [
    {
     "title": "Reddy YNV et al. A simple, evidence-based approach to help guide diagnosis of heart failure with preserved ejection fraction. Circulation 2018;138:861–70.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/29792299/"
    }
   ]
  },
  {
   "id": "ham-d",
   "name": "Hamilton Depression Rating Scale (HAM-D 17-item)",
   "short": "HAM-D",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/ham-d/",
   "summary": "The 17-item Hamilton Depression Rating Scale is a clinician-rated measure of depression severity scored 0–52. Recommended severity bands (Zimmerman 2013) are 0–7 no depression, 8–16 mild, 17–23 moderate and ≥24 severe; remission is usually defined as ≤7.",
   "formula": "Sum of 17 clinician-rated items. Items 1, 2, 3, 7, 8, 9, 10, 11 and 15 are scored 0–4; items 4, 5, 6, 12, 13, 14, 16 and 17 are scored 0–2. Range 0–52.",
   "inputs": [
    {
     "id": "q1",
     "label": "1. Depressed mood (sadness, hopeless, helpless, worthless)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Absent",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Indicated only on questioning",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Spontaneously reported verbally",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Communicated non-verbally (facial expression, posture, voice, tendency to weep)",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Virtually only these feelings reported, verbally and non-verbally",
       "points": 4
      }
     ]
    },
    {
     "id": "q2",
     "label": "2. Feelings of guilt",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Absent",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Self-reproach, feels he/she has let people down",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Ideas of guilt or rumination over past errors or sinful deeds",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Present illness is a punishment; delusions of guilt",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Hears accusatory or denunciatory voices and/or threatening visual hallucinations",
       "points": 4
      }
     ]
    },
    {
     "id": "q3",
     "label": "3. Suicide",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Absent",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Feels life is not worth living",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Wishes he/she were dead or any thoughts of possible death to self",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Suicidal ideas or gesture",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Attempts at suicide",
       "points": 4
      }
     ]
    },
    {
     "id": "q4",
     "label": "4. Insomnia: early (difficulty falling asleep)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No difficulty falling asleep",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Occasional difficulty falling asleep (more than ½ hour)",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Nightly difficulty falling asleep",
       "points": 2
      }
     ]
    },
    {
     "id": "q5",
     "label": "5. Insomnia: middle (waking during the night)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No difficulty",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Restless and disturbed during the night",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Waking during the night; any getting out of bed (except to void)",
       "points": 2
      }
     ]
    },
    {
     "id": "q6",
     "label": "6. Insomnia: late (early-morning waking)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No difficulty",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Waking in early hours but goes back to sleep",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Unable to fall asleep again if he/she gets out of bed",
       "points": 2
      }
     ]
    },
    {
     "id": "q7",
     "label": "7. Work and activities",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No difficulty",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Thoughts and feelings of incapacity, fatigue or weakness related to activities, work or hobbies",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Loss of interest in activities, hobbies or work (reported, or listlessness, indecision, vacillation)",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Decrease in actual time spent in activities or decrease in productivity",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Stopped working because of present illness",
       "points": 4
      }
     ]
    },
    {
     "id": "q8",
     "label": "8. Retardation (slowness of thought and speech, impaired concentration, decreased motor activity)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Normal speech and thought",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Slight retardation at interview",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Obvious retardation at interview",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Interview difficult",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Complete stupor",
       "points": 4
      }
     ]
    },
    {
     "id": "q9",
     "label": "9. Agitation",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: None",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Fidgetiness",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Playing with hands, hair, etc.",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Moving about, can't sit still",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Hand wringing, nail biting, hair-pulling, biting of lips",
       "points": 4
      }
     ]
    },
    {
     "id": "q10",
     "label": "10. Anxiety: psychic",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No difficulty",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Subjective tension and irritability",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Worrying about minor matters",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Apprehensive attitude apparent in face or speech",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Fears expressed without questioning",
       "points": 4
      }
     ]
    },
    {
     "id": "q11",
     "label": "11. Anxiety: somatic (GI, CV, respiratory, urinary frequency, sweating)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Absent",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Mild",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Moderate",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Severe",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Incapacitating",
       "points": 4
      }
     ]
    },
    {
     "id": "q12",
     "label": "12. Somatic symptoms: gastrointestinal",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: None",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Loss of appetite but eating without encouragement",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Difficulty eating without urging; requests laxatives or GI medication",
       "points": 2
      }
     ]
    },
    {
     "id": "q13",
     "label": "13. General somatic symptoms",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: None",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Heaviness in limbs, back or head; backaches, headache, muscle aches; loss of energy and fatigability",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Any clear-cut symptom",
       "points": 2
      }
     ]
    },
    {
     "id": "q14",
     "label": "14. Genital symptoms (loss of libido, menstrual disturbance)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Absent",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Mild",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Severe",
       "points": 2
      }
     ]
    },
    {
     "id": "q15",
     "label": "15. Hypochondriasis",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Not present",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Self-absorption (bodily)",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Preoccupation with health",
       "points": 2
      },
      {
       "value": "3",
       "label": "3: Frequent complaints, requests for help, etc.",
       "points": 3
      },
      {
       "value": "4",
       "label": "4: Hypochondriacal delusions",
       "points": 4
      }
     ]
    },
    {
     "id": "q16",
     "label": "16. Loss of weight",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: No weight loss (or <1 lb/week if measured)",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Probable weight loss associated with present illness (or >1 lb/week)",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Definite weight loss according to patient (or >2 lb/week)",
       "points": 2
      }
     ]
    },
    {
     "id": "q17",
     "label": "17. Insight",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0: Acknowledges being depressed and ill",
       "points": 0
      },
      {
       "value": "1",
       "label": "1: Acknowledges illness but attributes cause to bad food, climate, overwork, virus, need for rest, etc.",
       "points": 1
      },
      {
       "value": "2",
       "label": "2: Denies being ill at all",
       "points": 2
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Hamilton M. A rating scale for depression. J Neurol Neurosurg Psychiatry 1960;23:56–62.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/14399272/"
    },
    {
     "title": "Zimmerman M et al. Severity classification on the Hamilton Depression Rating Scale. J Affect Disord 2013;150:384–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/23759278/"
    }
   ]
  },
  {
   "id": "harris-benedict",
   "name": "Harris-Benedict Equation (Revised, Roza & Shizgal 1984)",
   "short": "Harris-Benedict",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/harris-benedict/",
   "summary": "Revised Harris-Benedict (Roza & Shizgal 1984) estimates resting energy expenditure: men 88.362 + 13.397W + 4.799H − 5.677A; women 447.593 + 9.247W + 3.098H − 4.330A (W kg, H cm, A years). Multiply by an activity or stress factor for total needs; precision is about ±14%.",
   "formula": "Men: 88.362 + 13.397 × W + 4.799 × H − 5.677 × A.  Women: 447.593 + 9.247 × W + 3.098 × H − 4.330 × A.  (W kg, H cm, A years)",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 20,
     "max": 400
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 100,
     "max": 250
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Roza AM, Shizgal HM. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. Am J Clin Nutr 1984;40:168–82.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/6741850/"
    }
   ]
  },
  {
   "id": "harvey-bradshaw",
   "name": "Harvey-Bradshaw Index (Crohn's Disease)",
   "short": "HBI",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/harvey-bradshaw/",
   "summary": "The Harvey-Bradshaw Index scores Crohn's disease activity from well-being, abdominal pain, liquid stools per day, abdominal mass and complications. A score <5 indicates remission, 5–7 mild, 8–16 moderate and >16 severe disease; a fall of ≥3 points indicates clinical response.",
   "formula": "HBI = well-being (0–4) + abdominal pain (0–3) + number of liquid stools yesterday + abdominal mass (0–3) + 1 per complication (arthralgia, uveitis, erythema nodosum, aphthous ulcers, pyoderma gangrenosum, anal fissure, new fistula, abscess)",
   "inputs": [
    {
     "id": "wellbeing",
     "label": "General well-being (yesterday)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Very well",
       "points": 0
      },
      {
       "value": "1",
       "label": "Slightly below par",
       "points": 1
      },
      {
       "value": "2",
       "label": "Poor",
       "points": 2
      },
      {
       "value": "3",
       "label": "Very poor",
       "points": 3
      },
      {
       "value": "4",
       "label": "Terrible",
       "points": 4
      }
     ]
    },
    {
     "id": "pain",
     "label": "Abdominal pain (yesterday)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "None",
       "points": 0
      },
      {
       "value": "1",
       "label": "Mild",
       "points": 1
      },
      {
       "value": "2",
       "label": "Moderate",
       "points": 2
      },
      {
       "value": "3",
       "label": "Severe",
       "points": 3
      }
     ]
    },
    {
     "id": "stools",
     "label": "Number of liquid or soft stools (yesterday)",
     "kind": "num",
     "min": 0,
     "max": 50
    },
    {
     "id": "mass",
     "label": "Abdominal mass",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "None",
       "points": 0
      },
      {
       "value": "1",
       "label": "Dubious",
       "points": 1
      },
      {
       "value": "2",
       "label": "Definite",
       "points": 2
      },
      {
       "value": "3",
       "label": "Definite and tender",
       "points": 3
      }
     ]
    },
    {
     "id": "arthralgia",
     "label": "Arthralgia",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "uveitis",
     "label": "Uveitis",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "en",
     "label": "Erythema nodosum",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "aphthous",
     "label": "Aphthous ulcers",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "pg",
     "label": "Pyoderma gangrenosum",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "fissure",
     "label": "Anal fissure",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "fistula",
     "label": "New fistula",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "abscess",
     "label": "Abscess",
     "kind": "yn",
     "points": 1,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Harvey RF, Bradshaw JM. A simple index of Crohn's-disease activity. Lancet 1980;1:514.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/6102236/"
    },
    {
     "title": "Vermeire S et al. Correlation between the Crohn's disease activity and Harvey-Bradshaw indices in assessing Crohn's disease severity. Clin Gastroenterol Hepatol 2010;8:357–63.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/20096379/"
    }
   ]
  },
  {
   "id": "has-bled",
   "name": "HAS-BLED Score for Major Bleeding Risk in Atrial Fibrillation",
   "short": "HAS-BLED",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/has-bled/",
   "summary": "HAS-BLED estimates 1-year major bleeding risk in atrial fibrillation patients on anticoagulation (0–9 points). A score ≥3 indicates high bleeding risk, which calls for closer follow-up and correction of modifiable factors, not withholding anticoagulation.",
   "formula": "H: uncontrolled hypertension (SBP > 160) 1 · A: abnormal renal 1, abnormal liver 1 · S: stroke 1 · B: bleeding history/predisposition 1 · L: labile INR 1 · E: elderly (> 65) 1 · D: antiplatelet/NSAID 1, alcohol ≥ 8 drinks/week 1",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "htn",
     "label": "Uncontrolled hypertension (SBP > 160 mmHg)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "renal",
     "label": "Abnormal renal function (dialysis, transplant or Cr ≥ 2.26 mg/dL / 200 µmol/L)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "liver",
     "label": "Abnormal liver function (cirrhosis, or bilirubin > 2× ULN with AST/ALT > 3× ULN)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "stroke",
     "label": "Prior stroke",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "bleeding",
     "label": "Prior major bleeding or predisposition to bleeding (e.g. anemia)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "inr",
     "label": "Labile INR (time in therapeutic range < 60%)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "drugs",
     "label": "Antiplatelet or NSAID use",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "alcohol",
     "label": "Alcohol use (≥ 8 drinks/week)",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Pisters R et al. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation. Chest 2010;138:1093–100.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/20299623/"
    }
   ]
  },
  {
   "id": "a1c-eag",
   "name": "HbA1c to Estimated Average Glucose (ADAG)",
   "short": "eAG",
   "category": "Endocrine & Metabolic",
   "url": "https://askcalc.site/calc/a1c-eag/",
   "summary": "Estimated average glucose (eAG) from HbA1c by the ADAG equation: eAG (mg/dL) = 28.7 × A1c − 46.7 (mmol/L = 1.59 × A1c − 2.59). An A1c of 7% corresponds to about 154 mg/dL (8.6 mmol/L).",
   "formula": "eAG (mg/dL) = 28.7 × A1c (%) − 46.7;  eAG (mmol/L) = 1.59 × A1c − 2.59.  IFCC (mmol/mol) = (A1c% − 2.15) × 10.929",
   "inputs": [
    {
     "id": "a1c",
     "label": "HbA1c",
     "kind": "num",
     "unit": "%",
     "units": [
      "%",
      "mmol/mol"
     ],
     "min": 3,
     "max": 20
    }
   ],
   "references": [
    {
     "title": "Nathan DM et al. Translating the A1C assay into estimated average glucose values. Diabetes Care 2008;31:1473–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18540046/"
    }
   ]
  },
  {
   "id": "heart-score",
   "name": "HEART Score for Major Cardiac Events in Chest Pain",
   "short": "HEART",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/heart-score/",
   "summary": "The HEART score (0–10) risk-stratifies emergency department chest pain for 6-week major adverse cardiac events: 0–3 low (MACE ~1.7%, candidate for early discharge), 4–6 moderate (~16.6%, observe/investigate), 7–10 high (~50%, early invasive strategy).",
   "formula": "History 0–2 · ECG 0–2 · Age (< 45: 0, 45–64: 1, ≥ 65: 2) · Risk factors (none 0, 1–2: 1, ≥ 3 or known atherosclerosis 2) · Troponin (≤ ULN 0, 1–3×: 1, > 3×: 2). Risk factors: hypertension, hypercholesterolemia, diabetes, obesity (BMI > 30), current or recent smoking, family history.",
   "inputs": [
    {
     "id": "history",
     "label": "History",
     "kind": "sel",
     "options": [
      {
       "value": "slight",
       "label": "Slightly suspicious",
       "points": 0
      },
      {
       "value": "moderate",
       "label": "Moderately suspicious",
       "points": 1
      },
      {
       "value": "high",
       "label": "Highly suspicious",
       "points": 2
      }
     ]
    },
    {
     "id": "ecg",
     "label": "ECG",
     "kind": "sel",
     "options": [
      {
       "value": "normal",
       "label": "Normal",
       "points": 0
      },
      {
       "value": "nonspecific",
       "label": "Non-specific repolarization disturbance (LBBB, LVH, paced, repolarization changes)",
       "points": 1
      },
      {
       "value": "st",
       "label": "Significant ST deviation",
       "points": 2
      }
     ]
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "risk",
     "label": "Risk factors",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "No known risk factors",
       "points": 0
      },
      {
       "value": "1-2",
       "label": "1–2 risk factors",
       "points": 1
      },
      {
       "value": "3+",
       "label": "≥ 3 risk factors or known atherosclerotic disease",
       "points": 2
      }
     ]
    },
    {
     "id": "troponin",
     "label": "Initial troponin",
     "kind": "sel",
     "options": [
      {
       "value": "normal",
       "label": "≤ normal limit",
       "points": 0
      },
      {
       "value": "1-3x",
       "label": "1–3× normal limit",
       "points": 1
      },
      {
       "value": ">3x",
       "label": "> 3× normal limit",
       "points": 2
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Six AJ, Backus BE, Kelder JC. Chest pain in the emergency room: value of the HEART score. Neth Heart J 2008;16:191–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18665203/"
    },
    {
     "title": "Backus BE et al. A prospective validation of the HEART score for chest pain patients at the emergency department. Int J Cardiol 2013;168:2153–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/23465250/"
    }
   ]
  },
  {
   "id": "hemorr2hages",
   "name": "HEMORR2HAGES Bleeding Risk Score",
   "short": "HEMORR2HAGES",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/hemorr2hages/",
   "summary": "HEMORR₂HAGES estimates bleeding risk on warfarin in elderly AF patients (0–12): 2 points for prior bleed, 1 for each other factor. Bleeds per 100 patient-years: 1.9 (0), 2.5 (1), 5.3 (2), 8.4 (3), 10.4 (4), 12.3 (≥5).",
   "formula": "H: hepatic or renal disease 1 · E: ethanol abuse 1 · M: malignancy 1 · O: older (age >75) 1 · R: reduced platelet count/function 1 · R₂: rebleeding (prior bleed) 2 · H: uncontrolled hypertension 1 · A: anemia 1 · G: genetic factors (CYP2C9) 1 · E: excessive fall risk 1 · S: stroke 1 (max 12)",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "hepatic_renal",
     "label": "Hepatic or renal disease",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "etoh",
     "label": "Ethanol abuse",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "malignancy",
     "label": "Malignancy",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "plt_reduced",
     "label": "Reduced platelet count or function (incl. aspirin)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "rebleed",
     "label": "Prior bleed",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "htn_uncontrolled",
     "label": "Uncontrolled hypertension",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "anemia",
     "label": "Anemia",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "genetic",
     "label": "Genetic factors (CYP2C9 variant)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "falls",
     "label": "Excessive fall risk (incl. neuropsychiatric disease)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "stroke",
     "label": "Prior stroke",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Gage BF et al. Clinical classification schemes for predicting hemorrhage: results from the National Registry of Atrial Fibrillation (NRAF). Am Heart J 2006;151:713–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16504638/"
    }
   ]
  },
  {
   "id": "hestia",
   "name": "Hestia Criteria for Outpatient Pulmonary Embolism Treatment",
   "short": "Hestia",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/hestia/",
   "summary": "Hestia is an 11-item checklist for confirmed acute PE: if all answers are \"no\", the patient is eligible for outpatient anticoagulation (2.0% recurrent VTE, 1.0% mortality at 3 months in the derivation study). Any \"yes\" means admit.",
   "formula": "Count of 11 yes/no criteria: hemodynamic instability · thrombolysis/embolectomy needed · active bleeding or high bleeding risk · O₂ >24 h for SaO₂ >90% · PE on anticoagulation · IV analgesia >24 h · medical/social reason to admit >24 h · CrCl <30 · severe liver impairment · pregnancy · history of HIT. Any positive → not eligible.",
   "inputs": [
    {
     "id": "unstable",
     "label": "Hemodynamically unstable (SBP <100 with HR >100, needs ICU, or catecholamines)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "lysis",
     "label": "Thrombolysis or embolectomy needed",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "bleeding",
     "label": "Active bleeding or high risk of bleeding",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "oxygen",
     "label": "Oxygen needed >24 h to keep SaO₂ >90%",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "on_anticoag",
     "label": "PE diagnosed while on anticoagulation",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "iv_pain",
     "label": "Severe pain needing IV analgesia >24 h",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "social",
     "label": "Medical or social reason for admission >24 h",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "crcl30",
     "label": "Creatinine clearance <30 mL/min",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "liver",
     "label": "Severe liver impairment",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "pregnant",
     "label": "Pregnant",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "hit",
     "label": "Documented history of heparin-induced thrombocytopenia",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Zondag W et al. Outpatient treatment in patients with acute pulmonary embolism: the Hestia Study. J Thromb Haemost 2011;9:1500–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/21645235/"
    }
   ]
  },
  {
   "id": "homa-ir",
   "name": "HOMA-IR (Homeostatic Model Assessment of Insulin Resistance)",
   "short": "HOMA-IR",
   "category": "Endocrine & Metabolic",
   "url": "https://askcalc.site/calc/homa-ir/",
   "summary": "HOMA-IR = fasting glucose (mg/dL) × fasting insulin (µU/mL) ÷ 405 (or glucose in mmol/L × insulin ÷ 22.5). Higher values mean more insulin resistance; there is no universal cut-off, but values above about 2.5 are commonly taken to suggest insulin resistance in adults.",
   "formula": "HOMA-IR = glucose (mg/dL) × insulin (µU/mL) ÷ 405 = glucose (mmol/L) × insulin ÷ 22.5.  HOMA-%β = 20 × insulin ÷ (glucose mmol/L − 3.5).",
   "inputs": [
    {
     "id": "glucose",
     "label": "Fasting glucose",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 30,
     "max": 600
    },
    {
     "id": "insulin",
     "label": "Fasting insulin",
     "kind": "num",
     "unit": "µU/mL",
     "units": [
      "µU/mL",
      "pmol/L"
     ],
     "min": 0.5,
     "max": 500
    }
   ],
   "references": [
    {
     "title": "Matthews DR et al. Homeostasis model assessment: insulin resistance and β-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia 1985;28:412–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3899825/"
    }
   ]
  },
  {
   "id": "hscore",
   "name": "HScore for Reactive Hemophagocytic Lymphohistiocytosis (HLH)",
   "short": "HScore",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/hscore/",
   "summary": "The HScore (Fardet 2014) estimates the probability of reactive hemophagocytic syndrome from 9 clinical, laboratory and marrow features (0–337 points). The best cutoff is 169 (sensitivity 93%, specificity 86%); probability is <1% at ≤90 and >99% at ≥250.",
   "formula": "Immunosuppression 18 · Temp <38.4 0 / 38.4–39.4 33 / >39.4 49 · Organomegaly none 0 / liver or spleen 23 / both 38 · Cytopenias (Hb ≤9.2 g/dL, WBC ≤5 ×10⁹/L, plt ≤110 ×10⁹/L): 1 lineage 0 / 2 24 / 3 34 · Ferritin <2000 0 / 2000–6000 35 / >6000 50 ng/mL · TG <1.5 0 / 1.5–4 44 / >4 64 mmol/L · Fibrinogen >2.5 0 / ≤2.5 30 g/L · AST <30 0 / ≥30 19 U/L · Marrow hemophagocytosis 35. Probability = linear interpolation of Fardet 2014 Table 5 (published every 10 points).",
   "inputs": [
    {
     "id": "immuno",
     "label": "Known underlying immunosuppression (HIV or long-term immunosuppressive therapy)",
     "kind": "yn",
     "points": 18
    },
    {
     "id": "temp",
     "label": "Maximum temperature",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 30,
     "max": 45
    },
    {
     "id": "organomegaly",
     "label": "Organomegaly",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "one",
       "label": "Hepatomegaly or splenomegaly",
       "points": 23
      },
      {
       "value": "both",
       "label": "Hepatomegaly and splenomegaly",
       "points": 38
      }
     ]
    },
    {
     "id": "hgb",
     "label": "Hemoglobin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 2,
     "max": 25
    },
    {
     "id": "wbc",
     "label": "White cell count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 500
    },
    {
     "id": "plt",
     "label": "Platelet count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 2000
    },
    {
     "id": "ferritin",
     "label": "Ferritin",
     "kind": "num",
     "unit": "ng/mL",
     "units": [
      "ng/mL",
      "µg/L"
     ],
     "min": 1,
     "max": 500000
    },
    {
     "id": "tg",
     "label": "Triglycerides (fasting)",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mg/dL"
     ],
     "min": 0.1,
     "max": 60
    },
    {
     "id": "fibrinogen",
     "label": "Fibrinogen",
     "kind": "num",
     "unit": "g/L",
     "units": [
      "g/L",
      "mg/dL"
     ],
     "min": 0.1,
     "max": 15
    },
    {
     "id": "ast",
     "label": "AST (SGOT)",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 1,
     "max": 20000
    },
    {
     "id": "marrow",
     "label": "Hemophagocytosis on bone marrow aspirate",
     "kind": "yn",
     "points": 35,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Fardet L et al. Development and validation of the HScore, a score for the diagnosis of reactive hemophagocytic syndrome. Arthritis Rheumatol 2014;66:2613–20.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/24782338/"
    }
   ]
  },
  {
   "id": "hunt-hess",
   "name": "Hunt and Hess Scale for Subarachnoid Hemorrhage",
   "short": "Hunt-Hess",
   "category": "Neurology",
   "url": "https://askcalc.site/calc/hunt-hess/",
   "summary": "The Hunt and Hess scale grades aneurysmal subarachnoid haemorrhage I–V from the clinical picture (I minimal headache → V deep coma). The original 1968 scale adds one grade for serious systemic disease or severe vasospasm on angiography. Higher grade means higher surgical risk and mortality.",
   "formula": "Grade I–V by clinical description; +1 grade for serious systemic disease or severe angiographic vasospasm (original scale).",
   "inputs": [
    {
     "id": "grade",
     "label": "Clinical grade",
     "kind": "sel",
     "options": [
      {
       "value": "1",
       "label": "I – Asymptomatic, or minimal headache and slight nuchal rigidity"
      },
      {
       "value": "2",
       "label": "II – Moderate-to-severe headache, nuchal rigidity, no deficit other than cranial nerve palsy"
      },
      {
       "value": "3",
       "label": "III – Drowsiness, confusion or mild focal deficit"
      },
      {
       "value": "4",
       "label": "IV – Stupor, moderate-to-severe hemiparesis, possible early decerebrate rigidity"
      },
      {
       "value": "5",
       "label": "V – Deep coma, decerebrate rigidity, moribund"
      }
     ]
    },
    {
     "id": "systemic",
     "label": "Serious systemic disease (HTN, DM, severe atherosclerosis, COPD) or severe vasospasm on angiography",
     "kind": "yn",
     "points": 1,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Hunt WE, Hess RM. Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg 1968;28:14–20.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/5635959/"
    }
   ]
  },
  {
   "id": "ich-score",
   "name": "ICH Score (Intracerebral Hemorrhage)",
   "short": "ICH Score",
   "category": "Neurology",
   "url": "https://askcalc.site/calc/ich-score/",
   "summary": "The ICH score (0–6) predicts 30-day mortality after spontaneous intracerebral haemorrhage from GCS, hematoma volume ≥30 mL, intraventricular extension, infratentorial origin and age ≥80. Observed 30-day mortality: 0 = 0%, 1 = 13%, 2 = 26%, 3 = 72%, 4 = 97%, 5 = 100%.",
   "formula": "GCS 3–4: 2, 5–12: 1, 13–15: 0 · Volume ≥30 mL: 1 · IVH: 1 · Infratentorial origin: 1 · Age ≥80: 1",
   "inputs": [
    {
     "id": "gcs",
     "label": "GCS on presentation",
     "kind": "num",
     "min": 3,
     "max": 15
    },
    {
     "id": "volume",
     "label": "ICH volume (ABC/2)",
     "kind": "num",
     "min": 0,
     "max": 300
    },
    {
     "id": "ivh",
     "label": "Intraventricular hemorrhage",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "infratentorial",
     "label": "Infratentorial origin",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    }
   ],
   "references": [
    {
     "title": "Hemphill JC 3rd et al. The ICH score: a simple, reliable grading scale for intracerebral hemorrhage. Stroke 2001;32:891–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11283388/"
    }
   ]
  },
  {
   "id": "ibw",
   "name": "Ideal Body Weight (Devine)",
   "short": "IBW",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/ibw/",
   "summary": "Devine ideal body weight: men 50 kg + 2.3 kg per inch over 5 feet; women 45.5 kg + 2.3 kg per inch over 5 feet. Used for drug dosing (e.g. aminoglycosides, CrCl) and, as ARDSNet predicted body weight, for setting tidal volume (6–8 mL/kg).",
   "formula": "IBW (kg) = 50 (men) or 45.5 (women) + 2.3 × (height in inches − 60)",
   "inputs": [
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 100,
     "max": 250
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Pai MP, Paloucek FP. The origin of the \"ideal\" body weight equations. Ann Pharmacother 2000;34:1066–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10981254/"
    }
   ]
  },
  {
   "id": "insulin-starting-dose",
   "name": "Inpatient Basal-Bolus Insulin Starting Dose (RABBIT 2)",
   "short": "Basal-bolus start",
   "category": "Endocrine & Metabolic",
   "url": "https://askcalc.site/calc/insulin-starting-dose/",
   "summary": "Weight-based inpatient basal-bolus insulin for non-critically ill adults with type 2 diabetes (RABBIT 2 trials): total daily dose 0.4 U/kg if glucose 140–200 mg/dL or 0.5 U/kg if 201–400 mg/dL (medical); 0.5 U/kg in general surgery, reduced to 0.3 U/kg if age ≥70 or creatinine ≥2.0 mg/dL. Give half as basal once daily and half as prandial insulin split over 3 meals.",
   "formula": "Medical (RABBIT 2): TDD = 0.4 U/kg if glucose 140–200 mg/dL, 0.5 U/kg if 201–400 mg/dL.  Surgical (RABBIT 2 Surgery): TDD = 0.5 U/kg, or 0.3 U/kg if age ≥70 y and/or creatinine ≥2.0 mg/dL.  50% basal once daily + 50% prandial divided before 3 meals.",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "glucose",
     "label": "Current blood glucose",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 140,
     "max": 400
    },
    {
     "id": "setting",
     "label": "Patient population",
     "kind": "sel",
     "options": [
      {
       "value": "medical",
       "label": "General medicine (RABBIT 2)"
      },
      {
       "value": "surgical",
       "label": "General surgery (RABBIT 2 Surgery)"
      }
     ]
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120,
     "optional": true
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Umpierrez GE et al. Randomized study of basal-bolus insulin therapy in the inpatient management of patients with type 2 diabetes (RABBIT 2 trial). Diabetes Care 2007;30:2181–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/17513708/"
    },
    {
     "title": "Umpierrez GE et al. Randomized study of basal-bolus insulin therapy in patients with type 2 diabetes undergoing general surgery (RABBIT 2 Surgery). Diabetes Care 2011;34:256–61.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/21228246/"
    }
   ]
  },
  {
   "id": "ipi-dlbcl",
   "name": "International Prognostic Index (IPI) for Aggressive Lymphoma",
   "short": "IPI",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/ipi-dlbcl/",
   "summary": "The IPI scores 5 adverse factors in aggressive non-Hodgkin lymphoma: age >60, stage III–IV, elevated LDH, ECOG ≥2 and >1 extranodal site. 0–1 is low risk (5-year OS 73%), 2 low-intermediate (51%), 3 high-intermediate (43%) and 4–5 high (26%) in the pre-rituximab era.",
   "formula": "1 point each: age >60 y · Ann Arbor stage III or IV · LDH > upper limit of normal · ECOG ≥2 · >1 extranodal site",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "stage",
     "label": "Ann Arbor stage",
     "kind": "sel",
     "options": [
      {
       "value": "I",
       "label": "Stage I"
      },
      {
       "value": "II",
       "label": "Stage II"
      },
      {
       "value": "III",
       "label": "Stage III"
      },
      {
       "value": "IV",
       "label": "Stage IV"
      }
     ]
    },
    {
     "id": "ldh_high",
     "label": "LDH above upper limit of normal",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "ecog",
     "label": "ECOG performance status",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "ECOG 0"
      },
      {
       "value": "1",
       "label": "ECOG 1"
      },
      {
       "value": "2",
       "label": "ECOG 2"
      },
      {
       "value": "3",
       "label": "ECOG 3"
      },
      {
       "value": "4",
       "label": "ECOG 4"
      }
     ]
    },
    {
     "id": "extranodal",
     "label": "Number of extranodal sites",
     "kind": "num",
     "min": 0,
     "max": 20
    }
   ],
   "references": [
    {
     "title": "International Non-Hodgkin's Lymphoma Prognostic Factors Project. A predictive model for aggressive non-Hodgkin's lymphoma. N Engl J Med 1993;329:987–94.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8141877/"
    }
   ]
  },
  {
   "id": "iron-deficit-ganzoni",
   "name": "Iron Deficit (Ganzoni Formula)",
   "short": "Ganzoni",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/iron-deficit-ganzoni/",
   "summary": "The Ganzoni formula estimates total body iron deficit for IV iron: weight (kg) × (target Hb − actual Hb, g/dL) × 2.4 + iron stores (500 mg if ≥35 kg). Default target Hb is 15 g/dL (13 g/dL below 35 kg, with stores 15 mg/kg).",
   "formula": "Total iron deficit (mg) = weight (kg) × (target Hb − actual Hb) (g/dL) × 2.4 + iron stores (mg). Stores = 500 mg if ≥35 kg, else 15 mg/kg. Target Hb 15 g/dL (≥35 kg) or 13 g/dL (<35 kg).",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 2,
     "max": 400
    },
    {
     "id": "hgb",
     "label": "Actual hemoglobin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 1,
     "max": 25
    },
    {
     "id": "target",
     "label": "Target hemoglobin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 8,
     "max": 18,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Ganzoni AM. Intravenous iron-dextran: therapeutic and experimental possibilities. Schweiz Med Wochenschr 1970;100:301–3.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/5413918/"
    }
   ]
  },
  {
   "id": "isth-dic",
   "name": "ISTH Overt DIC Score",
   "short": "ISTH DIC",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/isth-dic/",
   "summary": "The ISTH overt DIC score (0–8) combines platelet count, fibrin-related marker (D-dimer/FDP), PT prolongation and fibrinogen in a patient with an underlying disorder known to cause DIC. A score ≥5 is compatible with overt DIC; <5 is suggestive of non-overt DIC, repeat in 1–2 days.",
   "formula": "Platelets ≥100 = 0, 50–99 = 1, <50 = 2 · fibrin marker none 0, moderate 2, strong 3 · PT prolongation <3 s = 0, 3–6 s = 1, >6 s = 2 · fibrinogen ≥1 g/L = 0, <1 g/L = 1",
   "inputs": [
    {
     "id": "plt",
     "label": "Platelet count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 2000
    },
    {
     "id": "fibrin_marker",
     "label": "Fibrin-related marker (D-dimer / FDP)",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "No increase",
       "points": 0
      },
      {
       "value": "moderate",
       "label": "Moderate increase",
       "points": 2
      },
      {
       "value": "strong",
       "label": "Strong increase",
       "points": 3
      }
     ]
    },
    {
     "id": "pt_prolong",
     "label": "PT prolongation above upper limit of normal",
     "kind": "num",
     "unit": "s",
     "units": [
      "s"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "fibrinogen",
     "label": "Fibrinogen",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "g/L"
     ],
     "min": 0,
     "max": 1500
    }
   ],
   "references": [
    {
     "title": "Taylor FB Jr et al. Towards definition, clinical and laboratory criteria, and a scoring system for disseminated intravascular coagulation. Thromb Haemost 2001;86:1327–30.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11816725/"
    }
   ]
  },
  {
   "id": "due-date-from-ivf",
   "name": "IVF Due Date (Embryo Transfer Date)",
   "short": "IVF due date",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/due-date-from-ivf/",
   "summary": "For IVF pregnancies the due date is set from the embryo transfer date: EDD = transfer date + 266 days − embryo age, i.e. +261 days for a day-5 (blastocyst) transfer and +263 days for a day-3 transfer (ACOG).",
   "formula": "EDD = transfer date + (266 − embryo age in days)   ·   GA (days) = (date − transfer) + 14 + embryo age",
   "inputs": [
    {
     "id": "transfer",
     "label": "Embryo transfer date",
     "kind": "date"
    },
    {
     "id": "embryoDay",
     "label": "Embryo age at transfer",
     "kind": "sel",
     "options": [
      {
       "value": "3",
       "label": "Day 3 (cleavage stage)"
      },
      {
       "value": "5",
       "label": "Day 5 (blastocyst)"
      },
      {
       "value": "6",
       "label": "Day 6 (blastocyst)"
      }
     ]
    },
    {
     "id": "asOf",
     "label": "Calculate gestational age as of (optional)",
     "kind": "date",
     "optional": true
    }
   ],
   "references": [
    {
     "title": "ACOG Committee Opinion No 700: Methods for Estimating the Due Date. Obstet Gynecol 2017;129:e150–4.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/28426621/"
    }
   ]
  },
  {
   "id": "khorana",
   "name": "Khorana Score for Chemotherapy-Associated VTE",
   "short": "Khorana",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/khorana/",
   "summary": "The Khorana score predicts symptomatic VTE in ambulatory cancer patients starting chemotherapy (0–6). Score 0 is low risk (~0.8% at 2.5 months), 1–2 intermediate (~1.8%) and ≥3 high (~7%); ASCO suggests considering primary thromboprophylaxis at a score of ≥2.",
   "formula": "Stomach/pancreas 2 · lung, lymphoma, gynecologic, bladder, testicular 1 · pre-chemo platelets ≥350 ×10⁹/L 1 · Hb <10 g/dL or ESA use 1 · WBC >11 ×10⁹/L 1 · BMI ≥35 kg/m² 1",
   "inputs": [
    {
     "id": "site",
     "label": "Primary cancer site",
     "kind": "sel",
     "options": [
      {
       "value": "very_high",
       "label": "Very high risk: stomach, pancreas",
       "points": 2
      },
      {
       "value": "high",
       "label": "High risk: lung, lymphoma, gynecologic, bladder, testicular",
       "points": 1
      },
      {
       "value": "other",
       "label": "Other site (e.g. breast, colorectal, prostate)",
       "points": 0
      }
     ]
    },
    {
     "id": "plt",
     "label": "Platelet count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 2000
    },
    {
     "id": "hgb",
     "label": "Hemoglobin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 1,
     "max": 25
    },
    {
     "id": "esa",
     "label": "Using erythropoiesis-stimulating agent",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "wbc",
     "label": "White blood cell count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 500
    },
    {
     "id": "bmi",
     "label": "Body mass index",
     "kind": "num",
     "min": 10,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Khorana AA et al. Development and validation of a predictive model for chemotherapy-associated thrombosis. Blood 2008;111:4902–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18216292/"
    }
   ]
  },
  {
   "id": "kfre",
   "name": "Kidney Failure Risk Equation (KFRE, 4-variable)",
   "short": "KFRE",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/kfre/",
   "summary": "The 4-variable KFRE (age, sex, eGFR, urine ACR) predicts 2- and 5-year risk of kidney failure requiring dialysis or transplant in CKD G3–G5. A 5-year risk ≥3–5% supports nephrology referral; a 2-year risk >40% supports preparing for kidney replacement therapy.",
   "formula": "Risk = 1 − S₀^exp(L); L = −0.2201 × (age/10 − 7.036) + 0.2467 × (male − 0.5642) − 0.5567 × (eGFR/5 − 7.222) + 0.4510 × (ln ACR [mg/g] − 5.137). S₀ North America: 0.9750 (2 y), 0.9240 (5 y); non-North America: 0.9832 (2 y), 0.9365 (5 y). ACR mg/mmol × 8.84 = mg/g.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "egfr",
     "label": "eGFR",
     "kind": "num",
     "min": 5,
     "max": 60
    },
    {
     "id": "acr",
     "label": "Urine albumin:creatinine ratio (ACR)",
     "kind": "num",
     "unit": "mg/g",
     "units": [
      "mg/g",
      "mg/mmol"
     ],
     "min": 0.5,
     "max": 30000
    },
    {
     "id": "region",
     "label": "Calibration",
     "kind": "sel",
     "options": [
      {
       "value": "na",
       "label": "North America"
      },
      {
       "value": "non",
       "label": "Outside North America"
      }
     ],
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Tangri N et al. A predictive model for progression of chronic kidney disease to kidney failure. JAMA 2011;305:1553–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/21482743/"
    },
    {
     "title": "Tangri N et al. Multinational assessment of accuracy of equations for predicting risk of kidney failure: a meta-analysis. JAMA 2016;315:164–74.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/26757465/"
    },
    {
     "title": "KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD. Kidney Int 2024;105(4S):S117–S314.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/38490803/"
    }
   ]
  },
  {
   "id": "kings-college-criteria",
   "name": "King's College Criteria for Liver Transplant in Acute Liver Failure",
   "short": "King's College",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/kings-college-criteria/",
   "summary": "King's College Criteria identify acute liver failure patients unlikely to survive without transplant. Acetaminophen: arterial pH <7.30 after resuscitation, OR all of INR >6.5, creatinine >3.4 mg/dL (300 µmol/L) and grade III–IV encephalopathy. Non-acetaminophen: INR >6.5, OR any 3 of age <10 or >40, unfavourable aetiology, jaundice >7 days before encephalopathy, INR >3.5, bilirubin >17.5 mg/dL (300 µmol/L).",
   "formula": "Acetaminophen: pH <7.30 OR (INR >6.5 AND creatinine >3.4 mg/dL [300 µmol/L] AND grade III/IV encephalopathy). Non-acetaminophen: INR >6.5 OR ≥3 of: age <10 or >40; non-A non-B hepatitis, halothane or idiosyncratic drug reaction; jaundice → encephalopathy >7 days; INR >3.5; bilirubin >17.5 mg/dL (300 µmol/L).",
   "inputs": [
    {
     "id": "etiology",
     "label": "Cause of acute liver failure",
     "kind": "sel",
     "options": [
      {
       "value": "apap",
       "label": "Acetaminophen (paracetamol)"
      },
      {
       "value": "other",
       "label": "Non-acetaminophen"
      }
     ]
    },
    {
     "id": "ph",
     "label": "Arterial pH (after resuscitation)",
     "kind": "num",
     "min": 6.5,
     "max": 7.8,
     "optional": true
    },
    {
     "id": "inr",
     "label": "INR",
     "kind": "num",
     "min": 0.5,
     "max": 25,
     "optional": true
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25,
     "optional": true
    },
    {
     "id": "enceph",
     "label": "Hepatic encephalopathy grade",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None"
      },
      {
       "value": "g12",
       "label": "Grade I–II"
      },
      {
       "value": "g34",
       "label": "Grade III–IV"
      }
     ],
     "optional": true
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120,
     "optional": true
    },
    {
     "id": "unfav",
     "label": "Unfavourable aetiology (seronegative / non-A–E hepatitis, halothane, idiosyncratic drug reaction)",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "jdays",
     "label": "Days from jaundice to encephalopathy",
     "kind": "num",
     "min": 0,
     "max": 365,
     "optional": true
    },
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "O'Grady JG et al. Early indicators of prognosis in fulminant hepatic failure. Gastroenterology 1989;97:439–45.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/2490426/"
    },
    {
     "title": "Bernal W et al. Blood lactate as an early predictor of outcome in paracetamol-induced acute liver failure. Lancet 2002;359:558–63.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11867109/"
    }
   ]
  },
  {
   "id": "kocher-criteria",
   "name": "Kocher Criteria for Septic Arthritis of the Hip (Children)",
   "short": "Kocher criteria",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/kocher-criteria/",
   "summary": "Kocher criteria (non-weight-bearing, fever >38.5 °C, ESR >40 mm/h, WBC >12,000) distinguish septic arthritis of the hip from transient synovitis in children. Predicted probability of septic arthritis: 0 criteria 0.2%, 1 3%, 2 40%, 3 93%, 4 99.6%.",
   "formula": "1 point each: non-weight-bearing; temperature >38.5 °C; ESR >40 mm/h; WBC >12 ×10⁹/L. Probabilities from the derivation cohort.",
   "inputs": [
    {
     "id": "nwb",
     "label": "Non-weight-bearing on affected side",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "temp",
     "label": "Temperature (highest)",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 30,
     "max": 44
    },
    {
     "id": "esr",
     "label": "ESR",
     "kind": "num",
     "unit": "mm/h",
     "units": [
      "mm/h"
     ],
     "min": 0,
     "max": 200
    },
    {
     "id": "wbc",
     "label": "Serum WBC",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Kocher MS et al. Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm. J Bone Joint Surg Am 1999;81:1662–70.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10608376/"
    }
   ]
  },
  {
   "id": "lean-body-weight",
   "name": "Lean Body Weight (Janmahasatian)",
   "short": "LBW",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/lean-body-weight/",
   "summary": "Janmahasatian lean body weight (fat-free mass): men 9270 × W ÷ (6680 + 216 × BMI); women 9270 × W ÷ (8780 + 244 × BMI). Valid across extremes of body size and used for scaling drug doses in obesity.",
   "formula": "Men: LBW = 9270 × W ÷ (6680 + 216 × BMI).  Women: LBW = 9270 × W ÷ (8780 + 244 × BMI).  W in kg, BMI in kg/m².",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 20,
     "max": 400
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 100,
     "max": 250
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Janmahasatian S et al. Quantification of lean bodyweight. Clin Pharmacokinet 2005;44:1051–65.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16176118/"
    }
   ]
  },
  {
   "id": "lights-criteria",
   "name": "Light's Criteria for Pleural Effusion",
   "short": "Light's",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/lights-criteria/",
   "summary": "Light's criteria classify a pleural effusion as an exudate if ANY of: pleural/serum protein ratio >0.5, pleural/serum LDH ratio >0.6, or pleural LDH >2/3 of the upper limit of normal serum LDH. If none is met, it is a transudate.",
   "formula": "Exudate if any: pleural protein ÷ serum protein >0.5 · pleural LDH ÷ serum LDH >0.6 · pleural LDH >⅔ × upper limit of normal serum LDH",
   "inputs": [
    {
     "id": "pf_protein",
     "label": "Pleural fluid protein",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0,
     "max": 15
    },
    {
     "id": "s_protein",
     "label": "Serum total protein",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 1,
     "max": 15
    },
    {
     "id": "pf_ldh",
     "label": "Pleural fluid LDH",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 0,
     "max": 50000
    },
    {
     "id": "s_ldh",
     "label": "Serum LDH",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 10,
     "max": 50000
    },
    {
     "id": "ldh_uln",
     "label": "Upper limit of normal serum LDH",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 100,
     "max": 1000
    }
   ],
   "references": [
    {
     "title": "Light RW et al. Pleural effusions: the diagnostic separation of transudates and exudates. Ann Intern Med 1972;77:507–13.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4642731/"
    }
   ]
  },
  {
   "id": "lille",
   "name": "Lille Model (Day 7, Alcoholic Hepatitis)",
   "short": "Lille",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/lille/",
   "summary": "The Lille model assesses response to corticosteroids in severe alcohol-associated hepatitis using day-0 values and the change in bilirubin at day 7. A score ≥0.45 indicates non-response (6-month survival ~25%) and supports stopping steroids.",
   "formula": "R = 3.19 − 0.101 × age + 0.147 × albumin d0 (g/L) + 0.0165 × [bilirubin d0 − bilirubin d7] (µmol/L) − 0.206 × renal insufficiency (Cr >1.3 mg/dL) − 0.0065 × bilirubin d0 (µmol/L) − 0.0096 × PT (s). Lille = e^(−R) ÷ (1 + e^(−R)).",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "albumin",
     "label": "Albumin at day 0",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 7
    },
    {
     "id": "bili0",
     "label": "Bilirubin at day 0",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    },
    {
     "id": "bili7",
     "label": "Bilirubin at day 7",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    },
    {
     "id": "creat",
     "label": "Creatinine at day 0 (>1.3 mg/dL = renal insufficiency)",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "pt",
     "label": "Prothrombin time at day 0",
     "kind": "num",
     "min": 5,
     "max": 200
    }
   ],
   "references": [
    {
     "title": "Louvet A et al. The Lille model: a new tool for therapeutic strategy in patients with severe alcoholic hepatitis treated with steroids. Hepatology 2007;45:1348–54.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/17518367/"
    }
   ]
  },
  {
   "id": "maddrey-df",
   "name": "Maddrey Discriminant Function (Alcoholic Hepatitis)",
   "short": "Maddrey DF",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/maddrey-df/",
   "summary": "Maddrey's modified discriminant function = 4.6 × (patient PT − control PT) + bilirubin (mg/dL). A score ≥32 defines severe alcohol-associated hepatitis with high 1-month mortality, where corticosteroids may be considered.",
   "formula": "DF = 4.6 × [patient PT (s) − control PT (s)] + total bilirubin (mg/dL)   (bilirubin µmol/L ÷ 17.1)",
   "inputs": [
    {
     "id": "pt",
     "label": "Prothrombin time (patient)",
     "kind": "num",
     "min": 5,
     "max": 200
    },
    {
     "id": "ptControl",
     "label": "Control (reference) prothrombin time",
     "kind": "num",
     "min": 5,
     "max": 30,
     "optional": true
    },
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    }
   ],
   "references": [
    {
     "title": "Carithers RL Jr et al. Methylprednisolone therapy in patients with severe alcoholic hepatitis. Ann Intern Med 1989;110:685–90.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/2648927/"
    },
    {
     "title": "Maddrey WC et al. Corticosteroid therapy of alcoholic hepatitis. Gastroenterology 1978;75:193–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/352788/"
    }
   ]
  },
  {
   "id": "holliday-segar",
   "name": "Maintenance IV Fluids (Holliday-Segar 4-2-1 Rule)",
   "short": "Maintenance fluids",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/holliday-segar/",
   "summary": "Holliday-Segar maintenance fluid: 4 mL/kg/h for the first 10 kg, 2 mL/kg/h for the next 10 kg and 1 mL/kg/h for each kg above 20 (the 4-2-1 rule); daily equivalent 100/50/20 mL/kg/day. A 25 kg child needs 65 mL/h.",
   "formula": "mL/h = 4 × (first 10 kg) + 2 × (next 10 kg) + 1 × (each kg > 20)   ·   mL/day = 100 × (first 10 kg) + 50 × (next 10 kg) + 20 × (each kg > 20)",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 2,
     "max": 150
    }
   ],
   "references": [
    {
     "title": "Holliday MA, Segar WE. The maintenance need for water in parenteral fluid therapy. Pediatrics 1957;19:823–32.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/13431307/"
    }
   ]
  },
  {
   "id": "mascc",
   "name": "MASCC Risk Index for Febrile Neutropenia",
   "short": "MASCC",
   "category": "Infectious Disease",
   "url": "https://askcalc.site/calc/mascc/",
   "summary": "The MASCC risk index (0–26) identifies febrile neutropenic cancer patients at low risk of serious complications. A score ≥21 is low risk (candidates for oral/outpatient therapy if otherwise suitable); <21 is high risk and warrants inpatient IV antibiotics.",
   "formula": "Burden of illness: none/mild 5, moderate 3, severe 0 · no hypotension (SBP ≥90) 5 · no COPD 4 · solid tumor or hematologic malignancy without prior fungal infection 4 · no dehydration requiring IV fluids 3 · outpatient at fever onset 3 · age <60 2",
   "inputs": [
    {
     "id": "burden",
     "label": "Burden of illness (symptoms)",
     "kind": "sel",
     "options": [
      {
       "value": "mild",
       "label": "No or mild symptoms",
       "points": 5
      },
      {
       "value": "moderate",
       "label": "Moderate symptoms",
       "points": 3
      },
      {
       "value": "severe",
       "label": "Severe symptoms or moribund",
       "points": 0
      }
     ]
    },
    {
     "id": "hypotension",
     "label": "Hypotension (SBP <90 mmHg)",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "copd",
     "label": "Chronic obstructive pulmonary disease",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "tumor",
     "label": "Tumor type",
     "kind": "sel",
     "options": [
      {
       "value": "solid",
       "label": "Solid tumor",
       "points": 4
      },
      {
       "value": "heme_no_fungal",
       "label": "Hematologic malignancy, no previous fungal infection",
       "points": 4
      },
      {
       "value": "heme_fungal",
       "label": "Hematologic malignancy with previous fungal infection",
       "points": 0
      }
     ]
    },
    {
     "id": "dehydration",
     "label": "Dehydration requiring IV fluids",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "inpatient",
     "label": "Inpatient at onset of fever",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    }
   ],
   "references": [
    {
     "title": "Klastersky J et al. The Multinational Association for Supportive Care in Cancer risk index: a multinational scoring system for identifying low-risk febrile neutropenic cancer patients. J Clin Oncol 2000;18:3038–51.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10944139/"
    }
   ]
  },
  {
   "id": "map",
   "name": "Mean Arterial Pressure (MAP)",
   "short": "MAP",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/map/",
   "summary": "Mean arterial pressure ≈ (SBP + 2 × DBP) ÷ 3, i.e. diastolic plus one-third of pulse pressure. Normal is about 70–100 mmHg; a MAP ≥65 mmHg is the usual initial target in septic shock.",
   "formula": "MAP = (SBP + 2 × DBP) ÷ 3 = DBP + (SBP − DBP) ÷ 3",
   "inputs": [
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "dbp",
     "label": "Diastolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 200
    }
   ],
   "references": [
    {
     "title": "Meaney E et al. Formula and nomogram for the sphygmomanometric calculation of the mean arterial pressure. Heart 2000;84:64.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10862592/"
    }
   ]
  },
  {
   "id": "meld-3",
   "name": "MELD 3.0 (Kim 2021, OPTN 2023)",
   "short": "MELD 3.0",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/meld-3/",
   "summary": "MELD 3.0 adds female sex and albumin to MELD-Na with updated coefficients and a creatinine cap of 3.0 mg/dL; it has been used for US liver allocation since July 2023. Range 6–40; higher scores mean higher 90-day waitlist mortality (score 20 ≈ 5% 90-day mortality).",
   "formula": "MELD 3.0 = 1.33 (if female) + 4.56 ln(bili) + 0.82 (137 − Na) − 0.24 (137 − Na) ln(bili) + 9.09 ln(INR) + 11.14 ln(Cr) + 1.85 (3.5 − Alb) − 1.83 (3.5 − Alb) ln(Cr) + 6; rounded. Bounds: labs <1 → 1; Cr max 3.0 (3.0 if dialysis ≥2×/wk or CVVHD); Na 125–137; albumin 1.5–3.5 g/dL; max 40.",
   "inputs": [
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    },
    {
     "id": "inr",
     "label": "INR",
     "kind": "num",
     "min": 0.5,
     "max": 20
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 100,
     "max": 180
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 7
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "dialysis",
     "label": "Dialysis ≥2 times in the past week (or CVVHD ≥24 h)",
     "kind": "yn",
     "points": 0
    }
   ],
   "references": [
    {
     "title": "Kim WR et al. MELD 3.0: the Model for End-Stage Liver Disease updated for the modern era. Gastroenterology 2021;161:1887–95.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/34481845/"
    }
   ]
  },
  {
   "id": "meld",
   "name": "MELD Score (original UNOS MELD)",
   "short": "MELD",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/meld/",
   "summary": "The original MELD score (UNOS version) predicts 3-month mortality in cirrhosis from bilirubin, INR and creatinine; range 6–40. Scores ≥15 generally warrant transplant referral; MELD-Na and MELD 3.0 have since replaced it for US organ allocation.",
   "formula": "MELD = 10 × [0.957 × ln(Cr) + 0.378 × ln(bilirubin) + 1.120 × ln(INR) + 0.643], rounded. Values <1.0 set to 1.0; creatinine capped at 4.0 mg/dL and set to 4.0 if dialysed ≥2× in the past week (or CVVHD ≥24 h); maximum 40.",
   "inputs": [
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    },
    {
     "id": "inr",
     "label": "INR",
     "kind": "num",
     "min": 0.5,
     "max": 20
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "dialysis",
     "label": "Dialysis ≥2 times in the past week (or CVVHD ≥24 h)",
     "kind": "yn",
     "points": 0
    }
   ],
   "references": [
    {
     "title": "Kamath PS et al. A model to predict survival in patients with end-stage liver disease. Hepatology 2001;33:464–70.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11172350/"
    },
    {
     "title": "Malinchoc M et al. A model to predict poor survival in patients undergoing TIPS. Hepatology 2000;31:864–71.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10733541/"
    },
    {
     "title": "Wiesner R et al. MELD and allocation of donor livers. Gastroenterology 2003;124:91–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12512033/"
    }
   ]
  },
  {
   "id": "meld-na",
   "name": "MELD-Na Score (UNOS/OPTN 2016)",
   "short": "MELD-Na",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/meld-na/",
   "summary": "MELD-Na adds serum sodium (bounded 125–137 mmol/L) to MELD and was used for US liver allocation from 2016 to 2023. The sodium correction applies only when MELD >11; range 6–40, with referral for transplant evaluation usually at ≥15.",
   "formula": "MELD(i) = round[0.957 ln(Cr) + 0.378 ln(bili) + 1.120 ln(INR) + 0.643, 1 dp] × 10 (labs <1 → 1; Cr ≤4.0; dialysis ≥2×/wk → Cr 4.0). If MELD(i) >11: MELD-Na = MELD(i) + 1.32 × (137 − Na) − 0.033 × MELD(i) × (137 − Na), Na bounded 125–137 mmol/L; rounded, max 40.",
   "inputs": [
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 80
    },
    {
     "id": "inr",
     "label": "INR",
     "kind": "num",
     "min": 0.5,
     "max": 20
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 100,
     "max": 180
    },
    {
     "id": "dialysis",
     "label": "Dialysis ≥2 times in the past week (or CVVHD ≥24 h)",
     "kind": "yn",
     "points": 0
    }
   ],
   "references": [
    {
     "title": "Kim WR et al. Hyponatremia and mortality among patients on the liver-transplant waiting list. N Engl J Med 2008;359:1018–26.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18768945/"
    },
    {
     "title": "Kim WR et al. MELD 3.0: the Model for End-Stage Liver Disease updated for the modern era. Gastroenterology 2021;161:1887–95 (describes the OPTN MELD-Na rules).",
     "url": "https://pubmed.ncbi.nlm.nih.gov/34481845/"
    }
   ]
  },
  {
   "id": "mentzer-index",
   "name": "Mentzer Index (Thalassemia Trait vs Iron Deficiency)",
   "short": "Mentzer index",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/mentzer-index/",
   "summary": "Mentzer index = MCV (fL) ÷ RBC count (×10¹²/L). In microcytic anaemia, <13 suggests thalassaemia trait and >13 suggests iron deficiency.",
   "formula": "Mentzer index = MCV (fL) ÷ RBC (×10¹²/L, = millions/µL)",
   "inputs": [
    {
     "id": "mcv",
     "label": "MCV",
     "kind": "num",
     "min": 40,
     "max": 130
    },
    {
     "id": "rbc",
     "label": "Red cell count",
     "kind": "num",
     "unit": "×10¹²/L",
     "units": [
      "×10¹²/L",
      "×10⁶/µL"
     ],
     "min": 0.5,
     "max": 9
    }
   ],
   "references": [
    {
     "title": "Mentzer WC Jr. Differentiation of iron deficiency from thalassaemia trait. Lancet 1973;1:882.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4123424/"
    }
   ]
  },
  {
   "id": "mifflin-st-jeor",
   "name": "Mifflin-St Jeor Equation (Resting Energy Expenditure)",
   "short": "Mifflin-St Jeor",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/mifflin-st-jeor/",
   "summary": "Mifflin-St Jeor estimates resting energy expenditure: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (y) + 5 for men, or − 161 for women. It is the most accurate predictive equation for healthy and obese adults; multiply by an activity factor for total daily needs.",
   "formula": "REE (kcal/day) = 10 × W (kg) + 6.25 × H (cm) − 5 × A (y) + 5 (men) or − 161 (women)",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 20,
     "max": 400
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 100,
     "max": 250
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Mifflin MD et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51:241–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/2305711/"
    }
   ]
  },
  {
   "id": "milan-criteria",
   "name": "Milan Criteria for Liver Transplantation in Hepatocellular Carcinoma",
   "short": "Milan criteria",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/milan-criteria/",
   "summary": "Milan criteria: a single HCC ≤5 cm, or up to 3 tumours each ≤3 cm, with no macrovascular invasion and no extrahepatic spread. Patients within Milan have about 75% 4-year survival after liver transplant, similar to non-HCC indications.",
   "formula": "Within Milan = (1 tumour ≤5 cm OR 2–3 tumours each ≤3 cm) AND no macrovascular invasion AND no extrahepatic spread",
   "inputs": [
    {
     "id": "n",
     "label": "Number of tumours",
     "kind": "num",
     "min": 1,
     "max": 20
    },
    {
     "id": "size",
     "label": "Largest tumour diameter",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "mm"
     ],
     "min": 0.1,
     "max": 30
    },
    {
     "id": "vasc",
     "label": "Macrovascular invasion (e.g. portal vein tumour thrombus)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "extra",
     "label": "Extrahepatic spread (nodes or metastases)",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Mazzaferro V et al. Liver transplantation for the treatment of small hepatocellular carcinomas in patients with cirrhosis. N Engl J Med 1996;334:693–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8594428/"
    }
   ]
  },
  {
   "id": "modified-marshall",
   "name": "Modified Marshall Score for Organ Failure (Acute Pancreatitis)",
   "short": "Modified Marshall",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/modified-marshall/",
   "summary": "The modified Marshall score (revised Atlanta 2012) grades respiratory (PaO₂/FiO₂), renal (creatinine) and cardiovascular (systolic BP) function 0–4 each. A score ≥2 in any system defines organ failure; lasting >48 h it is persistent organ failure and defines severe acute pancreatitis.",
   "formula": "Respiratory P/F: >400 0, 301–400 1, 201–300 2, 101–200 3, ≤101 4 · Renal creatinine µmol/L: ≤134 0, 134–169 1, 170–310 2, 311–439 3, >439 4 · CV: SBP ≥90 0, <90 fluid-responsive 1, <90 not responsive 2, <90 & pH <7.3 3, <90 & pH <7.2 4",
   "inputs": [
    {
     "id": "pao2",
     "label": "PaO₂",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 20,
     "max": 700
    },
    {
     "id": "fio2",
     "label": "FiO₂ (blank = room air 21%)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 21,
     "max": 100,
     "optional": true
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "cv",
     "label": "Systolic BP / circulation",
     "kind": "sel",
     "options": [
      {
       "value": "normal",
       "label": "SBP ≥ 90 mmHg",
       "points": 0
      },
      {
       "value": "fluid-resp",
       "label": "SBP < 90, fluid responsive",
       "points": 1
      },
      {
       "value": "not-resp",
       "label": "SBP < 90, not fluid responsive",
       "points": 2
      },
      {
       "value": "ph73",
       "label": "SBP < 90 and pH < 7.3",
       "points": 3
      },
      {
       "value": "ph72",
       "label": "SBP < 90 and pH < 7.2",
       "points": 4
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Banks PA et al. Classification of acute pancreatitis—2012: revision of the Atlanta classification and definitions by international consensus. Gut 2013;62:102–11.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/23100216/"
    }
   ]
  },
  {
   "id": "opioid-mme",
   "name": "Morphine Milligram Equivalents (MME) Calculator, CDC 2022",
   "short": "MME",
   "category": "Pharmacology & Dosing",
   "url": "https://askcalc.site/calc/opioid-mme/",
   "summary": "Total daily morphine milligram equivalents (MME) from the CDC 2022 conversion factors (e.g. oxycodone 1.5, hydromorphone 5, methadone 4.7, fentanyl patch 2.4 per mcg/h). Overdose risk rises with dose; ≥50 MME/day warrants reassessment and naloxone, and ≥90 MME/day should be avoided or carefully justified. MME is a risk measure, not a tool for converting between opioids.",
   "formula": "MME/day = Σ (total daily dose × CDC 2022 conversion factor). Factors: codeine 0.15, dihydrocodeine 0.25, fentanyl patch 2.4 (per mcg/h), hydrocodone 1, hydromorphone 5, methadone 4.7, morphine 1, oxycodone 1.5, oxymorphone 3, tapentadol 0.4, tramadol 0.2.",
   "inputs": [
    {
     "id": "drug",
     "label": "Opioid",
     "kind": "sel",
     "options": [
      {
       "value": "morphine",
       "label": "Morphine (mg/day)"
      },
      {
       "value": "codeine",
       "label": "Codeine (mg/day)"
      },
      {
       "value": "dihydrocodeine",
       "label": "Dihydrocodeine (mg/day)"
      },
      {
       "value": "hydrocodone",
       "label": "Hydrocodone (mg/day)"
      },
      {
       "value": "hydromorphone",
       "label": "Hydromorphone (mg/day)"
      },
      {
       "value": "methadone",
       "label": "Methadone (mg/day)"
      },
      {
       "value": "oxycodone",
       "label": "Oxycodone (mg/day)"
      },
      {
       "value": "oxymorphone",
       "label": "Oxymorphone (mg/day)"
      },
      {
       "value": "tapentadol",
       "label": "Tapentadol (mg/day)"
      },
      {
       "value": "tramadol",
       "label": "Tramadol (mg/day)"
      },
      {
       "value": "fentanyl-patch",
       "label": "Fentanyl transdermal patch (mcg/h)"
      }
     ]
    },
    {
     "id": "dose",
     "label": "Total daily dose (mg/day; fentanyl patch: mcg/h)",
     "kind": "num",
     "min": 0,
     "max": 5000
    },
    {
     "id": "drug2",
     "label": "Second opioid (optional)",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None"
      },
      {
       "value": "morphine",
       "label": "Morphine (mg/day)"
      },
      {
       "value": "codeine",
       "label": "Codeine (mg/day)"
      },
      {
       "value": "dihydrocodeine",
       "label": "Dihydrocodeine (mg/day)"
      },
      {
       "value": "hydrocodone",
       "label": "Hydrocodone (mg/day)"
      },
      {
       "value": "hydromorphone",
       "label": "Hydromorphone (mg/day)"
      },
      {
       "value": "methadone",
       "label": "Methadone (mg/day)"
      },
      {
       "value": "oxycodone",
       "label": "Oxycodone (mg/day)"
      },
      {
       "value": "oxymorphone",
       "label": "Oxymorphone (mg/day)"
      },
      {
       "value": "tapentadol",
       "label": "Tapentadol (mg/day)"
      },
      {
       "value": "tramadol",
       "label": "Tramadol (mg/day)"
      },
      {
       "value": "fentanyl-patch",
       "label": "Fentanyl transdermal patch (mcg/h)"
      }
     ],
     "optional": true
    },
    {
     "id": "dose2",
     "label": "Second opioid total daily dose (mg/day; fentanyl patch: mcg/h)",
     "kind": "num",
     "min": 0,
     "max": 5000,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Dowell D et al. CDC Clinical Practice Guideline for Prescribing Opioids for Pain — United States, 2022. MMWR Recomm Rep 2022;71(3):1–95.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/36327391/"
    }
   ]
  },
  {
   "id": "nafld-fibrosis-score",
   "name": "NAFLD Fibrosis Score",
   "short": "NFS",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/nafld-fibrosis-score/",
   "summary": "The NAFLD Fibrosis Score combines age, BMI, diabetes/IFG, AST/ALT ratio, platelets and albumin to estimate advanced fibrosis in fatty liver disease. Below −1.455 advanced fibrosis is unlikely; above 0.676 it is likely; values between are indeterminate.",
   "formula": "NFS = −1.675 + 0.037 × age + 0.094 × BMI + 1.13 × IFG/diabetes (1/0) + 0.99 × AST/ALT − 0.013 × platelets (10⁹/L) − 0.66 × albumin (g/dL)",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "bmi",
     "label": "BMI",
     "kind": "num",
     "min": 10,
     "max": 90
    },
    {
     "id": "ifg",
     "label": "Impaired fasting glucose or diabetes",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "ast",
     "label": "AST",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 1,
     "max": 20000
    },
    {
     "id": "alt",
     "label": "ALT",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 1,
     "max": 20000
    },
    {
     "id": "plt",
     "label": "Platelet count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 1,
     "max": 2000
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 7
    }
   ],
   "references": [
    {
     "title": "Angulo P et al. The NAFLD fibrosis score: a noninvasive system that identifies liver fibrosis in patients with NAFLD. Hepatology 2007;45:846–54.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/17393509/"
    },
    {
     "title": "McPherson S et al. Age as a confounding factor for the accurate non-invasive diagnosis of advanced NAFLD fibrosis. Am J Gastroenterol 2017;112:740–51.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/27725647/"
    }
   ]
  },
  {
   "id": "news2",
   "name": "NEWS2 (National Early Warning Score 2)",
   "short": "NEWS2",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/news2/",
   "summary": "NEWS2 (Royal College of Physicians, 2017) aggregates respiratory rate, SpO₂ (Scale 1, or Scale 2 for hypercapnic patients with target 88–92%), supplemental oxygen, systolic BP, pulse, consciousness (ACVPU) and temperature. 0–4 is low risk, a 3 in any single parameter needs urgent ward review, 5–6 is medium risk (urgent response) and ≥7 is high risk (emergency response).",
   "formula": "RR ≤8 3, 9–11 1, 12–20 0, 21–24 2, ≥25 3 · SpO₂ Scale 1: ≤91 3, 92–93 2, 94–95 1, ≥96 0 · SpO₂ Scale 2: ≤83 3, 84–85 2, 86–87 1, 88–92 (or ≥93 on air) 0, 93–94 on O₂ 1, 95–96 on O₂ 2, ≥97 on O₂ 3 · Supplemental O₂ 2 · SBP ≤90 3, 91–100 2, 101–110 1, 111–219 0, ≥220 3 · Pulse ≤40 3, 41–50 1, 51–90 0, 91–110 1, 111–130 2, ≥131 3 · New confusion/V/P/U 3 · Temp ≤35.0 3, 35.1–36.0 1, 36.1–38.0 0, 38.1–39.0 1, ≥39.1 2",
   "inputs": [
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 80
    },
    {
     "id": "spo2",
     "label": "SpO₂",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 40,
     "max": 100
    },
    {
     "id": "scale",
     "label": "SpO₂ scale",
     "kind": "sel",
     "options": [
      {
       "value": "1",
       "label": "Scale 1 (standard)"
      },
      {
       "value": "2",
       "label": "Scale 2 (hypercapnic respiratory failure, target 88–92%)"
      }
     ]
    },
    {
     "id": "o2",
     "label": "Air or oxygen",
     "kind": "sel",
     "options": [
      {
       "value": "air",
       "label": "Room air",
       "points": 0
      },
      {
       "value": "oxygen",
       "label": "Supplemental oxygen",
       "points": 2
      }
     ]
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "avpu",
     "label": "Consciousness (ACVPU)",
     "kind": "sel",
     "options": [
      {
       "value": "A",
       "label": "Alert",
       "points": 0
      },
      {
       "value": "CVPU",
       "label": "New confusion, or responds to Voice/Pain, or Unresponsive",
       "points": 3
      }
     ]
    },
    {
     "id": "temp",
     "label": "Temperature",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 20,
     "max": 45
    }
   ],
   "references": [
    {
     "title": "Royal College of Physicians. National Early Warning Score (NEWS) 2: Standardising the assessment of acute-illness severity in the NHS. London: RCP, 2017.",
     "url": "https://www.rcp.ac.uk/improving-care/resources/national-early-warning-score-news-2/"
    },
    {
     "title": "Smith GB et al. The ability of the National Early Warning Score (NEWS) to discriminate patients at risk of early cardiac arrest, unanticipated ICU admission, and death. Resuscitation 2013;84:465–70.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/23295778/"
    }
   ]
  },
  {
   "id": "nexus-c-spine",
   "name": "NEXUS Criteria for C-Spine Imaging",
   "short": "NEXUS",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/nexus-c-spine/",
   "summary": "After blunt trauma, cervical spine imaging is not required if all five NEXUS low-risk criteria are met: no posterior midline tenderness, no intoxication, normal alertness, no focal neurological deficit and no painful distracting injury. Sensitivity 99.6% in the validation cohort.",
   "formula": "No imaging if ALL: no posterior midline tenderness · no intoxication · normal alertness · no focal neuro deficit · no painful distracting injury.",
   "inputs": [
    {
     "id": "midline",
     "label": "Posterior midline cervical tenderness",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "intox",
     "label": "Evidence of intoxication",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "altered",
     "label": "Altered alertness",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "focal",
     "label": "Focal neurological deficit",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "distracting",
     "label": "Painful distracting injury",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Hoffman JR et al. Validity of a set of clinical criteria to rule out injury to the cervical spine in patients with blunt trauma. N Engl J Med 2000;343:94–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10891516/"
    }
   ]
  },
  {
   "id": "nihss",
   "name": "NIH Stroke Scale (NIHSS)",
   "short": "NIHSS",
   "category": "Neurology",
   "url": "https://askcalc.site/calc/nihss/",
   "summary": "The NIHSS quantifies acute stroke deficit across 15 items (total 0–42). 0 = no measurable deficit, 1–4 minor, 5–15 moderate, 16–20 moderate-to-severe, 21–42 severe stroke.",
   "formula": "Sum of 15 items: 1a LOC 0–3 · 1b questions 0–2 · 1c commands 0–2 · 2 gaze 0–2 · 3 visual 0–3 · 4 facial 0–3 · 5a/5b arms 0–4 each · 6a/6b legs 0–4 each · 7 ataxia 0–2 · 8 sensory 0–2 · 9 language 0–3 · 10 dysarthria 0–2 · 11 extinction 0–2. Max 42. UN items are not added.",
   "inputs": [
    {
     "id": "loc",
     "label": "1a. Level of consciousness",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – Alert",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Not alert, arousable by minor stimulation",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Not alert, needs repeated or painful stimulation",
       "points": 2
      },
      {
       "value": "3",
       "label": "3 – Unresponsive or reflex responses only",
       "points": 3
      }
     ]
    },
    {
     "id": "loc_q",
     "label": "1b. LOC questions (month, age)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – Answers both correctly",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Answers one correctly",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Answers neither correctly",
       "points": 2
      }
     ]
    },
    {
     "id": "loc_c",
     "label": "1c. LOC commands (open/close eyes, grip/release)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – Performs both tasks",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Performs one task",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Performs neither task",
       "points": 2
      }
     ]
    },
    {
     "id": "gaze",
     "label": "2. Best gaze",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – Normal",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Partial gaze palsy",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Forced deviation or total gaze paresis",
       "points": 2
      }
     ]
    },
    {
     "id": "visual",
     "label": "3. Visual fields",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – No visual loss",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Partial hemianopia",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Complete hemianopia",
       "points": 2
      },
      {
       "value": "3",
       "label": "3 – Bilateral hemianopia (blind incl. cortical blindness)",
       "points": 3
      }
     ]
    },
    {
     "id": "facial",
     "label": "4. Facial palsy",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – Normal symmetric movement",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Minor paralysis (flattened nasolabial fold)",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Partial paralysis (lower face)",
       "points": 2
      },
      {
       "value": "3",
       "label": "3 – Complete paralysis (upper and lower face)",
       "points": 3
      }
     ]
    },
    {
     "id": "arm_l",
     "label": "5a. Motor arm – left",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – No drift for 10 s",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Drift, does not hit bed",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Some effort against gravity",
       "points": 2
      },
      {
       "value": "3",
       "label": "3 – No effort against gravity, falls",
       "points": 3
      },
      {
       "value": "4",
       "label": "4 – No movement",
       "points": 4
      },
      {
       "value": "UN",
       "label": "UN – Amputation / joint fusion (not scored)",
       "points": 0
      }
     ]
    },
    {
     "id": "arm_r",
     "label": "5b. Motor arm – right",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – No drift for 10 s",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Drift, does not hit bed",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Some effort against gravity",
       "points": 2
      },
      {
       "value": "3",
       "label": "3 – No effort against gravity, falls",
       "points": 3
      },
      {
       "value": "4",
       "label": "4 – No movement",
       "points": 4
      },
      {
       "value": "UN",
       "label": "UN – Amputation / joint fusion (not scored)",
       "points": 0
      }
     ]
    },
    {
     "id": "leg_l",
     "label": "6a. Motor leg – left",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – No drift for 5 s",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Drift, does not hit bed",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Some effort against gravity",
       "points": 2
      },
      {
       "value": "3",
       "label": "3 – No effort against gravity, falls",
       "points": 3
      },
      {
       "value": "4",
       "label": "4 – No movement",
       "points": 4
      },
      {
       "value": "UN",
       "label": "UN – Amputation / joint fusion (not scored)",
       "points": 0
      }
     ]
    },
    {
     "id": "leg_r",
     "label": "6b. Motor leg – right",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – No drift for 5 s",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Drift, does not hit bed",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Some effort against gravity",
       "points": 2
      },
      {
       "value": "3",
       "label": "3 – No effort against gravity, falls",
       "points": 3
      },
      {
       "value": "4",
       "label": "4 – No movement",
       "points": 4
      },
      {
       "value": "UN",
       "label": "UN – Amputation / joint fusion (not scored)",
       "points": 0
      }
     ]
    },
    {
     "id": "ataxia",
     "label": "7. Limb ataxia",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – Absent (or cannot understand / paralysed)",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Present in one limb",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Present in two limbs",
       "points": 2
      }
     ]
    },
    {
     "id": "sensory",
     "label": "8. Sensory",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – Normal",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Mild-to-moderate sensory loss",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Severe to total sensory loss",
       "points": 2
      }
     ]
    },
    {
     "id": "language",
     "label": "9. Best language",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – No aphasia",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Mild-to-moderate aphasia",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Severe aphasia",
       "points": 2
      },
      {
       "value": "3",
       "label": "3 – Mute, global aphasia",
       "points": 3
      }
     ]
    },
    {
     "id": "dysarthria",
     "label": "10. Dysarthria",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – Normal",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Mild-to-moderate dysarthria",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Severe dysarthria (unintelligible or mute)",
       "points": 2
      },
      {
       "value": "UN",
       "label": "UN – Intubated / physical barrier (not scored)",
       "points": 0
      }
     ]
    },
    {
     "id": "extinction",
     "label": "11. Extinction and inattention (neglect)",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "0 – No abnormality",
       "points": 0
      },
      {
       "value": "1",
       "label": "1 – Inattention/extinction in one sensory modality",
       "points": 1
      },
      {
       "value": "2",
       "label": "2 – Profound hemi-inattention or in more than one modality",
       "points": 2
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Brott T et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke 1989;20:864–70.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/2749846/"
    }
   ]
  },
  {
   "id": "non-hdl-cholesterol",
   "name": "Non-HDL Cholesterol",
   "short": "Non-HDL-C",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/non-hdl-cholesterol/",
   "summary": "Non-HDL cholesterol = total cholesterol − HDL cholesterol; it captures all atherogenic (apoB) lipoproteins and is valid non-fasting. ATP III targets are 30 mg/dL above the LDL goal; <130 mg/dL (3.4 mmol/L) is desirable for primary prevention and ≥190 mg/dL is high.",
   "formula": "Non-HDL-C = total cholesterol − HDL-C. Goal = LDL-C goal + 30 mg/dL (0.8 mmol/L).",
   "inputs": [
    {
     "id": "tc",
     "label": "Total cholesterol",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 50,
     "max": 1000
    },
    {
     "id": "hdl",
     "label": "HDL cholesterol",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 5,
     "max": 200
    }
   ],
   "references": [
    {
     "title": "NCEP Expert Panel. Third Report of the NCEP Adult Treatment Panel III (ATP III) final report. Circulation 2002;106:3143–421.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12485966/"
    }
   ]
  },
  {
   "id": "nnt",
   "name": "Number Needed to Treat (NNT) / Harm (NNH)",
   "short": "NNT",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/nnt/",
   "summary": "From the control (CER) and experimental (EER) event rates: absolute risk reduction ARR = CER − EER, relative risk reduction RRR = ARR ÷ CER, and NNT = 1 ÷ ARR (rounded up). If the treatment increases events, the result is the number needed to harm (NNH).",
   "formula": "ARR = CER − EER · RR = EER ÷ CER · RRR = 1 − RR · NNT = 1 ÷ ARR (rounded up). If EER > CER: NNH = 1 ÷ (EER − CER).",
   "inputs": [
    {
     "id": "cer",
     "label": "Control event rate (%)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0,
     "max": 100
    },
    {
     "id": "eer",
     "label": "Experimental event rate (%)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Laupacis A, Sackett DL, Roberts RS. An assessment of clinically useful measures of the consequences of treatment. N Engl J Med 1988;318:1728–33.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3374545/"
    }
   ]
  },
  {
   "id": "oakland",
   "name": "Oakland Score for Lower GI Bleeding",
   "short": "Oakland",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/oakland/",
   "summary": "The Oakland score (0–35) predicts safe discharge in acute lower GI bleeding from age, sex, prior LGIB admission, rectal exam blood, heart rate, systolic BP and hemoglobin. A score ≤8 predicts a 95% probability of safe discharge for outpatient investigation (BSG 2019).",
   "formula": "Age <40 = 0, 40–69 = 1, ≥70 = 2 · Male 1 · Prior LGIB admission 1 · Blood on DRE 1 · HR <70 = 0, 70–89 = 1, 90–109 = 2, ≥110 = 3 · SBP 50–89 = 5, 90–119 = 4, 120–129 = 3, 130–159 = 2, ≥160 = 0 · Hb (g/L) 36–69 = 22, 70–89 = 17, 90–109 = 13, 110–129 = 8, 130–159 = 4, ≥160 = 0",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 16,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "prior",
     "label": "Previous admission with lower GI bleeding",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "dre",
     "label": "Blood on digital rectal examination",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 250
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "hgb",
     "label": "Hemoglobin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 2,
     "max": 25
    }
   ],
   "references": [
    {
     "title": "Oakland K et al. Derivation and validation of a novel risk score for safe discharge after acute lower gastrointestinal bleeding: a modelling study. Lancet Gastroenterol Hepatol 2017;2:635–43.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/28651935/"
    }
   ]
  },
  {
   "id": "orbit-bleeding",
   "name": "ORBIT Bleeding Risk Score for Atrial Fibrillation",
   "short": "ORBIT",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/orbit-bleeding/",
   "summary": "The ORBIT score (0–7) predicts major bleeding in AF patients on anticoagulation: 0–2 low (2.4 bleeds/100 patient-years), 3 medium (4.7), 4–7 high (8.1). Items: older age, reduced hemoglobin/anemia, bleeding history, insufficient kidney function, antiplatelet use.",
   "formula": "O: older (≥ 75) 1 · R: reduced Hb/Hct or anemia history 2 · B: bleeding history 2 · I: insufficient kidney function (eGFR < 60) 1 · T: treatment with antiplatelet 1",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "anemia",
     "label": "Reduced Hb (< 13 g/dL men, < 12 women), Hct (< 40% men, < 36% women) or history of anemia",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "bleeding",
     "label": "Bleeding history (GI, intracranial or hemorrhagic stroke)",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "renal",
     "label": "Insufficient kidney function (eGFR < 60)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "antiplatelet",
     "label": "Treatment with antiplatelet",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "O'Brien EC et al. The ORBIT bleeding score: a simple bedside score to assess bleeding risk in atrial fibrillation. Eur Heart J 2015;36:3258–64.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/26424865/"
    }
   ]
  },
  {
   "id": "ottawa-ankle",
   "name": "Ottawa Ankle Rules",
   "short": "Ottawa Ankle",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/ottawa-ankle/",
   "summary": "Ankle X-ray is indicated if there is malleolar-zone pain plus bone tenderness at the posterior edge or tip of either malleolus, or inability to bear weight (4 steps) both immediately and in the ED. Foot X-ray is indicated if there is midfoot-zone pain plus tenderness at the base of the 5th metatarsal or navicular, or inability to bear weight.",
   "formula": "Ankle series if malleolar-zone pain AND any: posterior edge/tip lateral malleolus tenderness · posterior edge/tip medial malleolus tenderness · unable to bear weight immediately and in ED. Foot series if midfoot-zone pain AND any: base of 5th MT tenderness · navicular tenderness · unable to bear weight.",
   "inputs": [
    {
     "id": "malleolar_pain",
     "label": "Pain in the malleolar zone",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "lat_mall",
     "label": "Bone tenderness: posterior edge or tip of lateral malleolus (distal 6 cm)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "med_mall",
     "label": "Bone tenderness: posterior edge or tip of medial malleolus (distal 6 cm)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "midfoot_pain",
     "label": "Pain in the midfoot zone",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "mt5",
     "label": "Bone tenderness: base of 5th metatarsal",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "navicular",
     "label": "Bone tenderness: navicular",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "no_wb",
     "label": "Unable to bear weight (4 steps) both immediately and in ED",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Stiell IG et al. A study to develop clinical decision rules for the use of radiography in acute ankle injuries. Ann Emerg Med 1992;21:384–90.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1554175/"
    },
    {
     "title": "Stiell IG et al. Decision rules for the use of radiography in acute ankle injuries. Refinement and prospective validation. JAMA 1993;269:1127–32.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8433468/"
    }
   ]
  },
  {
   "id": "ottawa-knee",
   "name": "Ottawa Knee Rule",
   "short": "Ottawa Knee",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/ottawa-knee/",
   "summary": "After acute knee injury, knee X-ray is indicated if any: age ≥55, isolated patellar tenderness, fibular head tenderness, inability to flex to 90°, or inability to bear weight (4 steps) both immediately and in the ED.",
   "formula": "X-ray if ANY: age ≥55 · isolated patellar tenderness · fibular head tenderness · inability to flex to 90° · inability to bear weight 4 steps immediately and in ED.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "patella",
     "label": "Isolated tenderness of the patella (no other bony tenderness)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "fibula",
     "label": "Tenderness at the head of the fibula",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "flex90",
     "label": "Unable to flex knee to 90°",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "no_wb",
     "label": "Unable to bear weight (4 steps) both immediately and in ED",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Stiell IG et al. Derivation of a decision rule for the use of radiography in acute knee injuries. Ann Emerg Med 1995;26:405–13.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/7574120/"
    },
    {
     "title": "Stiell IG et al. Implementation of the Ottawa Knee Rule for the use of radiography in acute knee injuries. JAMA 1997;278:2075–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9403421/"
    }
   ]
  },
  {
   "id": "ottawa-sah-rule",
   "name": "Ottawa Subarachnoid Hemorrhage (SAH) Rule",
   "short": "Ottawa SAH rule",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/ottawa-sah-rule/",
   "summary": "For alert patients ≥15 years with new severe non-traumatic headache peaking within 1 hour, SAH needs investigation if any is present: age ≥40, neck pain or stiffness, witnessed loss of consciousness, onset during exertion, thunderclap (instantly peaking) onset, or limited neck flexion. With none, SAH is ruled out (sensitivity 100%, specificity 15%).",
   "formula": "Positive if any: age ≥40 · neck pain or stiffness · witnessed loss of consciousness · onset during exertion · thunderclap (instantly peaking) headache · limited neck flexion on exam",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 15,
     "max": 120
    },
    {
     "id": "neck_pain",
     "label": "Neck pain or stiffness",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "loc",
     "label": "Witnessed loss of consciousness",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "exertion",
     "label": "Onset during exertion",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "thunderclap",
     "label": "Thunderclap headache (instantly peaking pain)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "neck_flexion",
     "label": "Limited neck flexion on examination",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Perry JJ et al. Clinical decision rules to rule out subarachnoid hemorrhage for acute headache. JAMA 2013;310:1248–55.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/24065011/"
    }
   ]
  },
  {
   "id": "oxygenation-index",
   "name": "Oxygenation Index (OI)",
   "short": "OI",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/oxygenation-index/",
   "summary": "Oxygenation index = (mean airway pressure × FiO₂ % ) ÷ PaO₂. In ventilated children (PALICC 2015), OI 4–8 is mild, 8–16 moderate and ≥16 severe pediatric ARDS; in neonates, OI >40 is a traditional ECMO threshold.",
   "formula": "OI = (mean airway pressure cmH₂O × FiO₂ %) ÷ PaO₂ mmHg",
   "inputs": [
    {
     "id": "mawp",
     "label": "Mean airway pressure (cmH₂O)",
     "kind": "num",
     "min": 1,
     "max": 60
    },
    {
     "id": "fio2",
     "label": "FiO₂ (% or fraction)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0.21,
     "max": 100
    },
    {
     "id": "pao2",
     "label": "PaO₂ (arterial)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 700
    }
   ],
   "references": [
    {
     "title": "Pediatric Acute Lung Injury Consensus Conference Group. Pediatric acute respiratory distress syndrome: consensus recommendations. Pediatr Crit Care Med 2015;16:428–39.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/25647235/"
    }
   ]
  },
  {
   "id": "pack-years",
   "name": "Pack-Years Smoking History",
   "short": "Pack-years",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/pack-years/",
   "summary": "Pack-years = packs smoked per day × years smoked (1 pack = 20 cigarettes). USPSTF 2021 recommends annual low-dose CT lung cancer screening for adults 50–80 with ≥20 pack-years who smoke now or quit within 15 years.",
   "formula": "Pack-years = (cigarettes per day ÷ 20) × years smoked",
   "inputs": [
    {
     "id": "ppd",
     "label": "Packs per day",
     "kind": "num",
     "unit": "packs/day",
     "units": [
      "packs/day",
      "cigarettes/day"
     ],
     "min": 0,
     "max": 10
    },
    {
     "id": "years",
     "label": "Years smoked",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "US Preventive Services Task Force. Screening for lung cancer: USPSTF recommendation statement. JAMA 2021;325:962–70.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/33687470/"
    }
   ]
  },
  {
   "id": "padua",
   "name": "Padua Prediction Score for VTE in Medical Inpatients",
   "short": "Padua",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/padua/",
   "summary": "The Padua Prediction Score stratifies VTE risk in hospitalized medical patients (0–20). A score ≥4 is high risk (11% VTE without prophylaxis vs 0.3% if <4), and pharmacologic thromboprophylaxis is recommended if bleeding risk allows.",
   "formula": "Active cancer 3 · previous VTE 3 · reduced mobility 3 · known thrombophilia 3 · trauma/surgery ≤1 month 2 · age ≥70 1 · heart/respiratory failure 1 · acute MI or ischemic stroke 1 · acute infection/rheumatologic disorder 1 · BMI ≥30 1 · ongoing hormonal treatment 1",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "cancer",
     "label": "Active cancer (local or distant metastases and/or chemo/radiotherapy in previous 6 months)",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "prior_vte",
     "label": "Previous VTE (excluding superficial vein thrombosis)",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "mobility",
     "label": "Reduced mobility (bed rest with bathroom privileges ≥ 3 days)",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "thrombophilia",
     "label": "Known thrombophilic condition",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "trauma_surg",
     "label": "Recent (≤ 1 month) trauma and/or surgery",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "hf_rf",
     "label": "Heart and/or respiratory failure",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "mi_stroke",
     "label": "Acute myocardial infarction or ischemic stroke",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "infection_rheum",
     "label": "Acute infection and/or rheumatologic disorder",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "obesity",
     "label": "Obesity (BMI ≥ 30)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "hormonal",
     "label": "Ongoing hormonal treatment",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Barbar S et al. A risk assessment model for the identification of hospitalized medical patients at risk for VTE: the Padua Prediction Score. J Thromb Haemost 2010;8:2450–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/20738765/"
    }
   ]
  },
  {
   "id": "pf-ratio",
   "name": "PaO2/FiO2 (P/F) Ratio with Berlin ARDS Severity",
   "short": "P/F ratio",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/pf-ratio/",
   "summary": "The PaO₂/FiO₂ ratio quantifies hypoxemia. Under the Berlin definition (with PEEP or CPAP ≥5 cmH₂O, acute onset, bilateral opacities and no cardiac explanation), ARDS is mild at 201–300 mmHg, moderate at 101–200 and severe at ≤100. Normal is roughly 400–500.",
   "formula": "P/F = PaO₂ (mmHg) ÷ FiO₂ (fraction). Berlin severity applies with PEEP or CPAP ≥5 cmH₂O.",
   "inputs": [
    {
     "id": "pao2",
     "label": "PaO₂ (arterial)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 700
    },
    {
     "id": "fio2",
     "label": "FiO₂ (% or fraction)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0.21,
     "max": 100
    },
    {
     "id": "peep",
     "label": "PEEP / CPAP (cmH₂O)",
     "kind": "num",
     "min": 0,
     "max": 40,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "ARDS Definition Task Force; Ranieri VM et al. Acute respiratory distress syndrome: the Berlin Definition. JAMA 2012;307:2526–33.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/22797452/"
    }
   ]
  },
  {
   "id": "parkland",
   "name": "Parkland Formula for Burn Resuscitation",
   "short": "Parkland",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/parkland/",
   "summary": "Parkland: 24-hour crystalloid (Ringer's lactate) = 4 mL × weight (kg) × %TBSA burned (partial + full thickness). Give half in the first 8 hours from the time of burn and the rest over the next 16 hours, titrated to urine output.",
   "formula": "Total 24 h = 4 mL × kg × %TBSA; ½ in first 8 h from injury, ½ over next 16 h.",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 0.3,
     "max": 400
    },
    {
     "id": "tbsa",
     "label": "%TBSA burned (partial + full thickness)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 1,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Baxter CR, Shires T. Physiological response to crystalloid resuscitation of severe burns. Ann N Y Acad Sci 1968;150:874–94.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4973463/"
    }
   ]
  },
  {
   "id": "mayo-uc-partial",
   "name": "Partial Mayo Score (Ulcerative Colitis)",
   "short": "Partial Mayo",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/mayo-uc-partial/",
   "summary": "The partial (non-invasive) Mayo score rates ulcerative colitis activity from stool frequency, rectal bleeding and physician global assessment (0–9) without endoscopy. Commonly: 0–1 remission, 2–4 mild, 5–6 moderate, 7–9 severe; a fall of ≥3 points best matched patient-reported improvement.",
   "formula": "Partial Mayo = stool frequency (0–3) + rectal bleeding (0–3) + physician global assessment (0–3). The full Mayo score adds the endoscopic subscore (0–3).",
   "inputs": [
    {
     "id": "stool",
     "label": "Stool frequency",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Normal for patient",
       "points": 0
      },
      {
       "value": "1",
       "label": "1–2 stools/day more than normal",
       "points": 1
      },
      {
       "value": "2",
       "label": "3–4 stools/day more than normal",
       "points": 2
      },
      {
       "value": "3",
       "label": "≥5 stools/day more than normal",
       "points": 3
      }
     ]
    },
    {
     "id": "bleeding",
     "label": "Rectal bleeding",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "No blood seen",
       "points": 0
      },
      {
       "value": "1",
       "label": "Streaks of blood with stool less than half the time",
       "points": 1
      },
      {
       "value": "2",
       "label": "Obvious blood with stool most of the time",
       "points": 2
      },
      {
       "value": "3",
       "label": "Blood alone passed",
       "points": 3
      }
     ]
    },
    {
     "id": "pga",
     "label": "Physician global assessment",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Normal",
       "points": 0
      },
      {
       "value": "1",
       "label": "Mild disease",
       "points": 1
      },
      {
       "value": "2",
       "label": "Moderate disease",
       "points": 2
      },
      {
       "value": "3",
       "label": "Severe disease",
       "points": 3
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Schroeder KW et al. Coated oral 5-aminosalicylic acid therapy for mildly to moderately active ulcerative colitis. N Engl J Med 1987;317:1625–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3317057/"
    },
    {
     "title": "Lewis JD et al. Use of the noninvasive components of the Mayo score to assess clinical response in ulcerative colitis. Inflamm Bowel Dis 2008;14:1660–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18623174/"
    }
   ]
  },
  {
   "id": "pecarn-febrile-infant",
   "name": "PECARN Febrile Infant Rule (29–60 days)",
   "short": "PECARN febrile infant",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/pecarn-febrile-infant/",
   "summary": "The PECARN rule classifies a well-appearing febrile infant (≥38.0 °C) as low risk for serious bacterial infection if the urinalysis is negative, ANC ≤ 4,090/µL and procalcitonin ≤ 1.71 ng/mL. Validation: sensitivity 97.7%, NPV 99.6%.",
   "formula": "Low risk if ALL: urinalysis negative (no LE, no nitrite, ≤ 5 WBC/hpf) AND ANC ≤ 4,090/µL AND procalcitonin ≤ 1.71 ng/mL",
   "inputs": [
    {
     "id": "ageDays",
     "label": "Age",
     "kind": "num",
     "min": 29,
     "max": 60
    },
    {
     "id": "uaPos",
     "label": "Positive urinalysis (any leukocyte esterase, nitrite, or > 5 WBC/hpf)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "anc",
     "label": "Absolute neutrophil count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL",
      "/µL",
      "/mm³"
     ],
     "min": 0,
     "max": 50
    },
    {
     "id": "pct",
     "label": "Procalcitonin",
     "kind": "num",
     "min": 0,
     "max": 500
    }
   ],
   "references": [
    {
     "title": "Kuppermann N et al. A clinical prediction rule to identify febrile infants 60 days and younger at low risk for serious bacterial infections. JAMA Pediatr 2019;173:342–51.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/30776077/"
    }
   ]
  },
  {
   "id": "pecarn-head-under2",
   "name": "PECARN Pediatric Head Injury Rule (< 2 years)",
   "short": "PECARN <2y",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/pecarn-head-under2/",
   "summary": "For children <2 years with minor head trauma (GCS 14–15): CT recommended if GCS 14/altered mental status or palpable skull fracture (ciTBI risk 4.4%); observation vs CT if non-frontal scalp hematoma, LOC ≥5 s, severe mechanism or not acting normally (0.9%); otherwise CT not recommended (<0.02%).",
   "formula": "Step 1: GCS 14 / altered mental status or palpable skull fracture → CT. Step 2: occipital/parietal/temporal scalp hematoma, LOC ≥5 s, severe mechanism, or not acting normally per parent → observation vs CT. Otherwise → no CT.",
   "inputs": [
    {
     "id": "ams",
     "label": "GCS 14 or other signs of altered mental status",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "skull_fx",
     "label": "Palpable skull fracture",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "hematoma",
     "label": "Occipital, parietal or temporal scalp hematoma",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "loc",
     "label": "Loss of consciousness ≥ 5 seconds",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "mechanism",
     "label": "Severe mechanism of injury",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "not_normal",
     "label": "Not acting normally per parent",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Kuppermann N et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. Lancet 2009;374:1160–70.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/19758692/"
    }
   ]
  },
  {
   "id": "pecarn-head-2plus",
   "name": "PECARN Pediatric Head Injury Rule (≥ 2 years)",
   "short": "PECARN ≥2y",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/pecarn-head-2plus/",
   "summary": "For children 2–17 years with minor head trauma (GCS 14–15): CT recommended if GCS 14/altered mental status or signs of basilar skull fracture (ciTBI risk 4.3%); observation vs CT if any LOC, vomiting, severe mechanism or severe headache (0.9%); otherwise CT not recommended (<0.05%).",
   "formula": "Step 1: GCS 14 / altered mental status or signs of basilar skull fracture → CT. Step 2: history of LOC, vomiting, severe mechanism, or severe headache → observation vs CT. Otherwise → no CT.",
   "inputs": [
    {
     "id": "ams",
     "label": "GCS 14 or other signs of altered mental status",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "basilar",
     "label": "Signs of basilar skull fracture",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "loc",
     "label": "History of loss of consciousness",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "vomit",
     "label": "History of vomiting",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "mechanism",
     "label": "Severe mechanism of injury",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "headache",
     "label": "Severe headache",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Kuppermann N et al. Identification of children at very low risk of clinically-important brain injuries after head trauma: a prospective cohort study. Lancet 2009;374:1160–70.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/19758692/"
    }
   ]
  },
  {
   "id": "pediatric-appendicitis-score",
   "name": "Pediatric Appendicitis Score (PAS, Samuel)",
   "short": "PAS",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/pediatric-appendicitis-score/",
   "summary": "The Pediatric Appendicitis Score (Samuel 2002) rates suspected appendicitis in children aged 4–15 on a 10-point scale. A score ≥6 is consistent with appendicitis (Samuel); ≤3 is low risk, and 4–5 is equivocal and usually warrants ultrasound or observation.",
   "formula": "Cough/percussion/hopping RLQ tenderness 2 · RIF tenderness 2 · anorexia 1 · fever ≥38 °C 1 · nausea/vomiting 1 · WBC >10 ×10⁹/L 1 · neutrophilia 1 · migration of pain to RLQ 1 (max 10)",
   "inputs": [
    {
     "id": "hop",
     "label": "Cough, percussion or hopping tenderness in RLQ",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "anorexia",
     "label": "Anorexia",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "fever",
     "label": "Pyrexia (≥38 °C)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "nausea",
     "label": "Nausea or vomiting",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "rlq_tender",
     "label": "Tenderness over right iliac fossa",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "wbc_high",
     "label": "Leukocytosis (WBC >10 ×10⁹/L)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "neutrophilia",
     "label": "Neutrophilia (ANC >7.5 ×10⁹/L)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "migration",
     "label": "Migration of pain to RLQ",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Samuel M. Pediatric appendicitis score. J Pediatr Surg 2002;37:877–81.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12037754/"
    }
   ]
  },
  {
   "id": "ett-size-peds",
   "name": "Pediatric Endotracheal Tube Size and Depth",
   "short": "Peds ETT size",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/ett-size-peds/",
   "summary": "Pediatric endotracheal tube internal diameter for children ≥2 years: uncuffed = (age/4) + 4 mm, cuffed = (age/4) + 3.5 mm. Oral insertion depth at the lip ≈ 3 × uncuffed tube ID (cm), or (age/2) + 12 cm.",
   "formula": "Uncuffed ID (mm) = age/4 + 4 (modified Cole) · Cuffed ID = age/4 + 3.5 (PALS) · Oral depth (cm) = 3 × ID or age/2 + 12",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years",
      "months"
     ],
     "min": 2,
     "max": 14
    }
   ],
   "references": [
    {
     "title": "Khine HH et al. Comparison of cuffed and uncuffed endotracheal tubes in young children during general anesthesia. Anesthesiology 1997;86:627–31.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9066329/"
    },
    {
     "title": "Cole F. Pediatric formulas for the anesthesiologist. AMA J Dis Child 1957;94:672–3.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/13478300/"
    },
    {
     "title": "Topjian AA et al. Part 4: Pediatric Basic and Advanced Life Support: 2020 AHA Guidelines for CPR and ECC. Circulation 2020;142:S469–523.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/33081526/"
    }
   ]
  },
  {
   "id": "pediatric-gcs",
   "name": "Pediatric Glasgow Coma Scale",
   "short": "Pediatric GCS",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/pediatric-gcs/",
   "summary": "The pediatric Glasgow Coma Scale (3–15) adapts verbal and motor responses for preverbal children: eye opening 1–4, verbal 1–5, motor 1–6. Severity: 13–15 mild, 9–12 moderate, ≤8 severe (consider airway protection).",
   "formula": "GCS = Eye (1–4) + Verbal (1–5) + Motor (1–6); preverbal descriptors for children ≤ 2 years",
   "inputs": [
    {
     "id": "eye",
     "label": "Eye opening",
     "kind": "sel",
     "options": [
      {
       "value": "4",
       "label": "Spontaneous",
       "points": 4
      },
      {
       "value": "3",
       "label": "To speech / sound",
       "points": 3
      },
      {
       "value": "2",
       "label": "To pain",
       "points": 2
      },
      {
       "value": "1",
       "label": "None",
       "points": 1
      }
     ]
    },
    {
     "id": "verbal",
     "label": "Verbal (preverbal infant / verbal child)",
     "kind": "sel",
     "options": [
      {
       "value": "5",
       "label": "Coos, babbles, smiles, follows objects / oriented",
       "points": 5
      },
      {
       "value": "4",
       "label": "Irritable cry but consolable / confused",
       "points": 4
      },
      {
       "value": "3",
       "label": "Cries to pain, inconsistently consolable, moaning / inappropriate words",
       "points": 3
      },
      {
       "value": "2",
       "label": "Moans to pain, inconsolable, agitated / incomprehensible sounds",
       "points": 2
      },
      {
       "value": "1",
       "label": "None",
       "points": 1
      }
     ]
    },
    {
     "id": "motor",
     "label": "Motor",
     "kind": "sel",
     "options": [
      {
       "value": "6",
       "label": "Moves spontaneously and purposefully / obeys commands",
       "points": 6
      },
      {
       "value": "5",
       "label": "Withdraws to touch / localises pain",
       "points": 5
      },
      {
       "value": "4",
       "label": "Withdraws to pain",
       "points": 4
      },
      {
       "value": "3",
       "label": "Abnormal flexion (decorticate)",
       "points": 3
      },
      {
       "value": "2",
       "label": "Extension (decerebrate)",
       "points": 2
      },
      {
       "value": "1",
       "label": "None",
       "points": 1
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Holmes JF et al. Performance of the pediatric Glasgow Coma Scale in children with blunt head trauma. Acad Emerg Med 2005;12:814–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16141014/"
    }
   ]
  },
  {
   "id": "apls-weight",
   "name": "Pediatric Weight Estimation by Age (APLS)",
   "short": "APLS weight",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/apls-weight/",
   "summary": "APLS (6th edition) age-based weight estimates for resuscitation: 0–12 months (0.5 × age in months) + 4 kg; 1–5 years (2 × age) + 8 kg; 6–12 years (3 × age) + 7 kg. Use a measured weight or length-based tape when available.",
   "formula": "0–12 mo: W = 0.5 × months + 4 · 1–5 y: W = 2 × years + 8 · 6–12 y: W = 3 × years + 7 (age in completed months/years)",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years",
      "months"
     ],
     "min": 0,
     "max": 12.999
    }
   ],
   "references": [
    {
     "title": "Luscombe MD, Owens BD, Burke D. Weight estimation in paediatrics: a comparison of the APLS formula and the formula \"Weight=3(age)+7\". Emerg Med J 2011;28:590–3.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/20659877/"
    }
   ]
  },
  {
   "id": "perc",
   "name": "PERC Rule for Pulmonary Embolism",
   "short": "PERC",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/perc/",
   "summary": "The PERC rule rules out PE without testing when pretest probability is low (<15%) and all 8 criteria are absent: age <50, HR <100, SpO₂ ≥95%, no hemoptysis, no estrogen use, no prior DVT/PE, no unilateral leg swelling, no recent surgery or trauma. Any positive criterion means PERC cannot be used to exclude PE.",
   "formula": "PERC negative only if ALL: age < 50 · HR < 100 · SpO₂ ≥ 95% · no hemoptysis · no estrogen use · no prior DVT/PE · no unilateral leg swelling · no surgery/trauma requiring hospitalization in past 4 weeks",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 300
    },
    {
     "id": "spo2",
     "label": "Oxygen saturation (SpO₂)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 40,
     "max": 100
    },
    {
     "id": "leg_swelling",
     "label": "Unilateral leg swelling",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "hemoptysis",
     "label": "Hemoptysis",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "surgery",
     "label": "Recent surgery or trauma (≤ 4 weeks, requiring general anesthesia/hospitalization)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "prior_vte",
     "label": "Previous DVT or PE",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "hormone",
     "label": "Hormone use (oral contraceptives, HRT or estrogen)",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Kline JA et al. Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism. J Thromb Haemost 2004;2:1247–55.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/15304025/"
    },
    {
     "title": "Kline JA et al. Prospective multicenter evaluation of the pulmonary embolism rule-out criteria. J Thromb Haemost 2008;6:772–80.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18318689/"
    }
   ]
  },
  {
   "id": "phq-9",
   "name": "PHQ-9 Depression Severity (Patient Health Questionnaire-9)",
   "short": "PHQ-9",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/phq-9/",
   "summary": "The PHQ-9 scores the nine DSM depression criteria from 0 (not at all) to 3 (nearly every day) over the last 2 weeks, total 0–27. Scores of 5, 10, 15 and 20 mark mild, moderate, moderately severe and severe depression; ≥10 has 88% sensitivity and specificity for major depression. Any positive answer to item 9 needs a same-day suicide risk assessment.",
   "formula": "Sum of 9 items, each 0 (not at all), 1 (several days), 2 (more than half the days), 3 (nearly every day) over the past 2 weeks. Range 0–27.",
   "inputs": [
    {
     "id": "q1",
     "label": "Little interest or pleasure in doing things",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q2",
     "label": "Feeling down, depressed, or hopeless",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q3",
     "label": "Trouble falling or staying asleep, or sleeping too much",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q4",
     "label": "Feeling tired or having little energy",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q5",
     "label": "Poor appetite or overeating",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q6",
     "label": "Feeling bad about yourself, or that you are a failure or have let yourself or your family down",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q7",
     "label": "Trouble concentrating on things, such as reading the newspaper or watching television",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q8",
     "label": "Moving or speaking so slowly that others could notice, or being so fidgety or restless that you move around a lot more than usual",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    },
    {
     "id": "q9",
     "label": "Thoughts that you would be better off dead, or of hurting yourself in some way",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "Not at all",
       "points": 0
      },
      {
       "value": "1",
       "label": "Several days",
       "points": 1
      },
      {
       "value": "2",
       "label": "More than half the days",
       "points": 2
      },
      {
       "value": "3",
       "label": "Nearly every day",
       "points": 3
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Kroenke K, Spitzer RL, Williams JB. The PHQ-9: validity of a brief depression severity measure. J Gen Intern Med 2001;16:606–13.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11556941/"
    }
   ]
  },
  {
   "id": "pitt-bacteremia",
   "name": "Pitt Bacteremia Score",
   "short": "Pitt",
   "category": "Infectious Disease",
   "url": "https://askcalc.site/calc/pitt-bacteremia/",
   "summary": "The Pitt bacteremia score grades acute illness severity in bloodstream infection from temperature, hypotension, mechanical ventilation, cardiac arrest and mental status (0–14). A score ≥4 indicates critical illness and is associated with substantially higher mortality.",
   "formula": "Temperature: ≤35.0 °C 2, 35.1–36.0 1, 36.1–38.9 0, 39.0–39.9 1, ≥40.0 2 · hypotension 2 · mechanical ventilation 2 · cardiac arrest 4 · mental status: alert 0, disoriented 1, stuporous 2, comatose 4",
   "inputs": [
    {
     "id": "temp",
     "label": "Temperature (oral)",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 20,
     "max": 45
    },
    {
     "id": "hypotension",
     "label": "Hypotension (acute SBP drop >30 and DBP drop >20 mmHg, SBP <90, or vasopressors)",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "vent",
     "label": "Mechanical ventilation",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "arrest",
     "label": "Cardiac arrest",
     "kind": "yn",
     "points": 4
    },
    {
     "id": "mental",
     "label": "Mental status",
     "kind": "sel",
     "options": [
      {
       "value": "alert",
       "label": "Alert",
       "points": 0
      },
      {
       "value": "disoriented",
       "label": "Disoriented",
       "points": 1
      },
      {
       "value": "stupor",
       "label": "Stuporous",
       "points": 2
      },
      {
       "value": "coma",
       "label": "Comatose",
       "points": 4
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Paterson DL et al. International prospective study of Klebsiella pneumoniae bacteremia: implications of extended-spectrum β-lactamase production in nosocomial infections. Ann Intern Med 2004;140:26–32.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/14706969/"
    },
    {
     "title": "Chow JW et al. Enterobacter bacteremia: clinical features and emergence of antibiotic resistance during therapy. Ann Intern Med 1991;115:585–90.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1892329/"
    }
   ]
  },
  {
   "id": "plasmic",
   "name": "PLASMIC Score for TTP",
   "short": "PLASMIC",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/plasmic/",
   "summary": "The PLASMIC score (0–7) estimates the probability of severe ADAMTS13 deficiency (TTP) in thrombotic microangiopathy. 0–4 is low risk (0–4%), 5 intermediate (5–24%) and 6–7 high risk (62–82%), favouring urgent plasma exchange pending ADAMTS13.",
   "formula": "1 point each: Platelets <30 ×10⁹/L · hemoLysis · no Active cancer · no Stem-cell/solid-organ transplant · MCV <90 fL · INR <1.5 · Creatinine <2.0 mg/dL",
   "inputs": [
    {
     "id": "plt",
     "label": "Platelet count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 2000
    },
    {
     "id": "hemolysis",
     "label": "Hemolysis (retic >2.5%, undetectable haptoglobin, or indirect bilirubin >2 mg/dL)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "cancer",
     "label": "Active cancer (treated within the past year)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "transplant",
     "label": "History of solid-organ or stem-cell transplant",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "mcv",
     "label": "MCV",
     "kind": "num",
     "unit": "fL",
     "units": [
      "fL"
     ],
     "min": 40,
     "max": 150
    },
    {
     "id": "inr",
     "label": "INR",
     "kind": "num",
     "min": 0.5,
     "max": 15
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    }
   ],
   "references": [
    {
     "title": "Bendapudi PK et al. Derivation and external validation of the PLASMIC score for rapid assessment of adults with thrombotic microangiopathies. Lancet Haematol 2017;4:e157–64.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/28259520/"
    }
   ]
  },
  {
   "id": "psi-port",
   "name": "Pneumonia Severity Index (PSI / PORT Score)",
   "short": "PSI",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/psi-port/",
   "summary": "The Pneumonia Severity Index (Fine 1997) assigns community-acquired pneumonia patients to risk classes I–V by age, comorbidity, exam and lab findings. Classes I–II (≤70 points) are generally suitable for outpatient care, class III (71–90) for brief observation, and classes IV (91–130) and V (>130) for admission, with 30-day mortality about 8–9% and 27–31%.",
   "formula": "Age (years; women −10) · nursing home +10 · neoplastic +30 · liver +20 · CHF +10 · cerebrovascular +10 · renal +10 · altered mental status +20 · RR ≥30 +20 · SBP <90 +20 · T <35 or ≥40 °C +15 · HR ≥125 +10 · pH <7.35 +30 · BUN ≥30 mg/dL (11 mmol/L) +20 · Na <130 +20 · glucose ≥250 mg/dL (14 mmol/L) +10 · Hct <30% +10 · PaO₂ <60 mmHg or SpO₂ <90% +10 · pleural effusion +10",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "nursing_home",
     "label": "Nursing home resident",
     "kind": "yn",
     "points": 10,
     "optional": true
    },
    {
     "id": "neoplastic",
     "label": "Neoplastic disease (active cancer)",
     "kind": "yn",
     "points": 30,
     "optional": true
    },
    {
     "id": "liver",
     "label": "Liver disease",
     "kind": "yn",
     "points": 20,
     "optional": true
    },
    {
     "id": "chf",
     "label": "Congestive heart failure",
     "kind": "yn",
     "points": 10,
     "optional": true
    },
    {
     "id": "cvd",
     "label": "Cerebrovascular disease",
     "kind": "yn",
     "points": 10,
     "optional": true
    },
    {
     "id": "renal",
     "label": "Renal disease",
     "kind": "yn",
     "points": 10,
     "optional": true
    },
    {
     "id": "ams",
     "label": "Altered mental status",
     "kind": "yn",
     "points": 20,
     "optional": true
    },
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 80
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "temp",
     "label": "Temperature",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 20,
     "max": 45
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "ph",
     "label": "Arterial pH",
     "kind": "num",
     "min": 6.5,
     "max": 8,
     "optional": true
    },
    {
     "id": "bun",
     "label": "BUN (or urea in mmol/L)",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300,
     "optional": true
    },
    {
     "id": "na",
     "label": "Sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200,
     "optional": true
    },
    {
     "id": "glucose",
     "label": "Glucose",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 10,
     "max": 3000,
     "optional": true
    },
    {
     "id": "hct",
     "label": "Hematocrit",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 5,
     "max": 80,
     "optional": true
    },
    {
     "id": "pao2",
     "label": "PaO₂ (arterial)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 700,
     "optional": true
    },
    {
     "id": "spo2",
     "label": "SpO₂",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 40,
     "max": 100,
     "optional": true
    },
    {
     "id": "effusion",
     "label": "Pleural effusion on imaging",
     "kind": "yn",
     "points": 10,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Fine MJ et al. A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med 1997;336:243–50.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8995086/"
    }
   ]
  },
  {
   "id": "likelihood-ratio-posttest",
   "name": "Post-Test Probability from Likelihood Ratio (Bayes)",
   "short": "Post-test probability",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/likelihood-ratio-posttest/",
   "summary": "Converts a pre-test probability to a post-test probability with a likelihood ratio: post-test odds = pre-test odds × LR. Enter an LR directly, or sensitivity, specificity and whether the test was positive (LR+ = sens ÷ (1 − spec); LR− = (1 − sens) ÷ spec).",
   "formula": "Pre-test odds = p ÷ (1 − p) · Post-test odds = pre-test odds × LR · Post-test probability = odds ÷ (1 + odds). LR+ = sens ÷ (1 − spec); LR− = (1 − sens) ÷ spec.",
   "inputs": [
    {
     "id": "pretest",
     "label": "Pre-test probability (%)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0.01,
     "max": 99.99
    },
    {
     "id": "lr",
     "label": "Likelihood ratio (if known)",
     "kind": "num",
     "min": 0.0001,
     "max": 10000,
     "optional": true
    },
    {
     "id": "sens",
     "label": "Sensitivity (%) (if LR not given)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0,
     "max": 100,
     "optional": true
    },
    {
     "id": "spec",
     "label": "Specificity (%) (if LR not given)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0,
     "max": 100,
     "optional": true
    },
    {
     "id": "result",
     "label": "Test result (if using sens/spec)",
     "kind": "sel",
     "options": [
      {
       "value": "positive",
       "label": "Positive"
      },
      {
       "value": "negative",
       "label": "Negative"
      }
     ],
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Jaeschke R, Guyatt GH, Sackett DL. Users' guides to the medical literature III. How to use an article about a diagnostic test. B. What are the results and will they help me in caring for my patients? JAMA 1994;271:703–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8309035/"
    }
   ]
  },
  {
   "id": "pram",
   "name": "PRAM (Pediatric Respiratory Assessment Measure) for Asthma",
   "short": "PRAM",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/pram/",
   "summary": "PRAM scores acute asthma severity in children (0–12) from suprasternal retraction, scalene contraction, air entry, wheezing and SpO₂. 0–3 mild, 4–7 moderate, 8–12 severe; a change of 3 points is clinically important.",
   "formula": "Suprasternal retraction 0/2 · scalene contraction 0/2 · air entry normal 0 / decreased at bases 1 / widespread 2 / absent-minimal 3 · wheeze absent 0 / expiratory 1 / inspiratory ± expiratory 2 / audible or silent chest 3 · SpO₂ ≥95% 0 / 92–94% 1 / <92% 2 (room air)",
   "inputs": [
    {
     "id": "suprasternal",
     "label": "Suprasternal retractions",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "scalene",
     "label": "Scalene muscle contraction",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "air_entry",
     "label": "Air entry",
     "kind": "sel",
     "options": [
      {
       "value": "normal",
       "label": "Normal",
       "points": 0
      },
      {
       "value": "bases",
       "label": "Decreased at the bases",
       "points": 1
      },
      {
       "value": "widespread",
       "label": "Widespread decrease (apex and base)",
       "points": 2
      },
      {
       "value": "minimal",
       "label": "Absent or minimal",
       "points": 3
      }
     ]
    },
    {
     "id": "wheeze",
     "label": "Wheezing",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "Absent",
       "points": 0
      },
      {
       "value": "expiratory",
       "label": "Expiratory only",
       "points": 1
      },
      {
       "value": "inspiratory",
       "label": "Inspiratory (± expiratory)",
       "points": 2
      },
      {
       "value": "audible",
       "label": "Audible without stethoscope or silent chest",
       "points": 3
      }
     ]
    },
    {
     "id": "spo2",
     "label": "Oxygen saturation (SpO₂)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 40,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Chalut DS, Ducharme FM, Davis GM. The Preschool Respiratory Assessment Measure (PRAM): a responsive index of acute asthma severity. J Pediatr 2000;137:762–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11113831/"
    },
    {
     "title": "Ducharme FM et al. The Pediatric Respiratory Assessment Measure: a valid clinical score for assessing acute asthma severity from toddlers to teenagers. J Pediatr 2008;152:476–80.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18346499/"
    }
   ]
  },
  {
   "id": "due-date",
   "name": "Pregnancy Due Date Calculator (Naegele's Rule from LMP)",
   "short": "Due date (LMP)",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/due-date/",
   "summary": "Naegele's rule estimates the due date as the first day of the last menstrual period (LMP) plus 280 days (40 weeks), adjusted by (cycle length − 28) days for non-28-day cycles. If a date is given, it also returns gestational age in weeks and days.",
   "formula": "EDD = LMP + 280 days + (cycle length − 28) days   ·   GA (days) = (date − LMP) − (cycle length − 28)",
   "inputs": [
    {
     "id": "lmp",
     "label": "First day of last menstrual period (LMP)",
     "kind": "date"
    },
    {
     "id": "cycle",
     "label": "Usual cycle length",
     "kind": "num",
     "min": 20,
     "max": 45,
     "optional": true
    },
    {
     "id": "asOf",
     "label": "Calculate gestational age as of (optional)",
     "kind": "date",
     "optional": true
    }
   ],
   "references": [
    {
     "title": "ACOG Committee Opinion No 700: Methods for Estimating the Due Date. Obstet Gynecol 2017;129:e150–4.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/28426621/"
    }
   ]
  },
  {
   "id": "pc-ptsd-5",
   "name": "Primary Care PTSD Screen for DSM-5 (PC-PTSD-5)",
   "short": "PC-PTSD-5",
   "category": "Psychiatry & Substance Use",
   "url": "https://askcalc.site/calc/pc-ptsd-5/",
   "summary": "The PC-PTSD-5 is a 5-item yes/no PTSD screen for people who report a traumatic event, scored 0–5. The VA National Center for PTSD recommends a cut-point of 4 (best balance of false positives and negatives); a cut-point of 3 is more sensitive. Positive screens need a full PTSD assessment.",
   "formula": "If trauma exposure is endorsed, score 1 point for each \"yes\" to the 5 past-month items (nightmares/intrusive thoughts, avoidance, on guard/startle, numb/detached, guilt/blame). Range 0–5. No trauma exposure = 0.",
   "inputs": [
    {
     "id": "trauma",
     "label": "Ever experienced an unusually or especially frightening, horrible or traumatic event (e.g. serious accident, assault, disaster, war, witnessing a death)?",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "nightmares",
     "label": "Had nightmares about the event(s) or thought about the event(s) when you did not want to?",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "avoidance",
     "label": "Tried hard not to think about the event(s) or went out of your way to avoid situations that reminded you of the event(s)?",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "on_guard",
     "label": "Been constantly on guard, watchful, or easily startled?",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "numb",
     "label": "Felt numb or detached from people, activities, or your surroundings?",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "guilt",
     "label": "Felt guilty or unable to stop blaming yourself or others for the event(s) or any problems the event(s) may have caused?",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Prins A et al. The Primary Care PTSD Screen for DSM-5 (PC-PTSD-5): development and evaluation within a veteran primary care sample. J Gen Intern Med 2016;31:1206–11.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/27170304/"
    },
    {
     "title": "VA National Center for PTSD. Primary Care PTSD Screen for DSM-5 (PC-PTSD-5).",
     "url": "https://www.ptsd.va.gov/professional/assessment/screens/pc-ptsd.asp"
    }
   ]
  },
  {
   "id": "pesi",
   "name": "Pulmonary Embolism Severity Index (PESI)",
   "short": "PESI",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/pesi/",
   "summary": "PESI predicts 30-day mortality in acute PE from 11 clinical variables. Class I (≤65) and II (66–85) are low risk (0–3.5% mortality) and may suit outpatient treatment; classes III–V (>85) carry 3.2–24.5% mortality.",
   "formula": "Age (years) · male +10 · cancer +30 · chronic heart failure +10 · chronic lung disease +10 · HR ≥ 110 +20 · SBP < 100 +30 · RR ≥ 30 +20 · temperature < 36 °C +20 · altered mental status +60 · SaO₂ < 90% +20",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "cancer",
     "label": "Cancer (active or history)",
     "kind": "yn",
     "points": 30
    },
    {
     "id": "chf",
     "label": "Chronic heart failure",
     "kind": "yn",
     "points": 10
    },
    {
     "id": "lung",
     "label": "Chronic lung disease",
     "kind": "yn",
     "points": 10
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 300
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 4,
     "max": 80
    },
    {
     "id": "temp",
     "label": "Temperature",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 25,
     "max": 45
    },
    {
     "id": "ams",
     "label": "Altered mental status (disorientation, lethargy, stupor or coma)",
     "kind": "yn",
     "points": 60
    },
    {
     "id": "spo2",
     "label": "Arterial oxygen saturation (SaO₂)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 40,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Aujesky D et al. Derivation and validation of a prognostic model for pulmonary embolism. Am J Respir Crit Care Med 2005;172:1041–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16020800/"
    }
   ]
  },
  {
   "id": "qsofa",
   "name": "qSOFA (Quick SOFA) Score for Sepsis",
   "short": "qSOFA",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/qsofa/",
   "summary": "qSOFA flags adults with suspected infection at higher risk of death or prolonged ICU stay: respiratory rate ≥22, altered mentation (GCS <15) and systolic BP ≤100 mmHg, one point each. A score ≥2 indicates high risk and should prompt assessment for organ dysfunction (full SOFA).",
   "formula": "One point each: RR ≥22/min · altered mentation (GCS <15) · SBP ≤100 mmHg",
   "inputs": [
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 80
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "ams",
     "label": "Altered mentation (GCS <15)",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Seymour CW et al. Assessment of clinical criteria for sepsis (Sepsis-3). JAMA 2016;315:762–74.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/26903335/"
    },
    {
     "title": "Singer M et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA 2016;315:801–10.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/26903338/"
    }
   ]
  },
  {
   "id": "ranson",
   "name": "Ranson Criteria for Acute Pancreatitis",
   "short": "Ranson",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/ranson/",
   "summary": "Ranson's criteria score acute pancreatitis with 5 admission and 6 (non-gallstone) or 5 (gallstone) 48-hour criteria. A score ≥3 indicates severe pancreatitis; historical mortality is ~1% for 0–2, ~15% for 3–4, ~40% for 5–6 and near 100% for ≥7.",
   "formula": "Non-gallstone — admission: age >55, WBC >16, glucose >200 mg/dL (11.1 mmol/L), LDH >350 U/L, AST >250 U/L; 48 h: Hct fall >10 points, BUN rise >5 mg/dL (1.8 mmol/L), Ca <8 mg/dL (2.0 mmol/L), PaO₂ <60 mmHg, base deficit >4, fluid sequestration >6 L. Gallstone — admission: age >70, WBC >18, glucose >220 mg/dL (12.2 mmol/L), LDH >400, AST >250; 48 h: Hct fall >10, BUN rise >2 mg/dL (0.7 mmol/L), Ca <8, base deficit >5, fluid sequestration >4 L. One point each.",
   "inputs": [
    {
     "id": "etiology",
     "label": "Etiology",
     "kind": "sel",
     "options": [
      {
       "value": "non-gallstone",
       "label": "Non-gallstone (e.g. alcohol)"
      },
      {
       "value": "gallstone",
       "label": "Gallstone (biliary)"
      }
     ]
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 12,
     "max": 120
    },
    {
     "id": "wbc",
     "label": "White blood cell count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0.1,
     "max": 300
    },
    {
     "id": "glucose",
     "label": "Glucose (admission)",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 10,
     "max": 2000
    },
    {
     "id": "ldh",
     "label": "LDH (admission)",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 10,
     "max": 20000
    },
    {
     "id": "ast",
     "label": "AST",
     "kind": "num",
     "unit": "U/L",
     "units": [
      "U/L"
     ],
     "min": 1,
     "max": 20000
    },
    {
     "id": "hctDrop",
     "label": "Hematocrit fall over 48 h (percentage points)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": -30,
     "max": 40,
     "optional": true
    },
    {
     "id": "bunRise",
     "label": "BUN rise over 48 h",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": -100,
     "max": 200,
     "optional": true
    },
    {
     "id": "calcium",
     "label": "Lowest serum calcium within 48 h",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 2,
     "max": 20,
     "optional": true
    },
    {
     "id": "pao2",
     "label": "Arterial PaO₂ within 48 h (non-gallstone only)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 20,
     "max": 700,
     "optional": true
    },
    {
     "id": "baseDeficit",
     "label": "Base deficit within 48 h",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": -30,
     "max": 40,
     "optional": true
    },
    {
     "id": "fluidSeq",
     "label": "Estimated fluid sequestration over 48 h (L)",
     "kind": "num",
     "min": -10,
     "max": 40,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Ranson JH et al. Prognostic signs and the role of operative management in acute pancreatitis. Surg Gynecol Obstet 1974;139:69–81.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4834279/"
    },
    {
     "title": "Ranson JH. Etiological and prognostic factors in human acute pancreatitis: a review. Am J Gastroenterol 1982;77:633–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/7051819/"
    }
   ]
  },
  {
   "id": "reticulocyte-index",
   "name": "Reticulocyte Production Index (Corrected Reticulocyte Count)",
   "short": "RPI",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/reticulocyte-index/",
   "summary": "The reticulocyte production index corrects the reticulocyte percentage for the degree of anemia (× Hct/45) and for prolonged circulation of premature reticulocytes (÷ maturation time, 1.0–2.5 days by hematocrit). RPI <2 in anemia indicates inadequate marrow response (hypoproliferative); RPI ≥2 suggests hemolysis or blood loss with an appropriate response.",
   "formula": "Corrected retic (%) = retic % × Hct ÷ 45.  RPI = corrected retic ÷ maturation time; maturation time = 1.0 d (Hct >35%), 1.5 d (26–35%), 2.0 d (16–25%), 2.5 d (≤15%).",
   "inputs": [
    {
     "id": "retic",
     "label": "Reticulocyte count",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0,
     "max": 50
    },
    {
     "id": "hct",
     "label": "Hematocrit",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 5,
     "max": 70
    }
   ],
   "references": [
    {
     "title": "Hillman RS. Characteristics of marrow production and reticulocyte maturation in normal man in response to anemia. J Clin Invest 1969;48:443–53.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/5773082/"
    }
   ]
  },
  {
   "id": "rcri",
   "name": "Revised Cardiac Risk Index (RCRI, Lee Index)",
   "short": "RCRI",
   "category": "Surgery & Perioperative",
   "url": "https://askcalc.site/calc/rcri/",
   "summary": "The RCRI counts 6 predictors of major cardiac complications after noncardiac surgery: high-risk surgery, ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes and creatinine >2.0 mg/dL. Risk rises from 0.4% (0 points) to 11% (≥3) in the original cohort.",
   "formula": "One point each: high-risk surgery · ischemic heart disease · congestive heart failure · cerebrovascular disease · insulin-treated diabetes · preoperative creatinine > 2.0 mg/dL (177 µmol/L)",
   "inputs": [
    {
     "id": "high_risk_surgery",
     "label": "High-risk surgery (intraperitoneal, intrathoracic or suprainguinal vascular)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "ihd",
     "label": "Ischemic heart disease",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "chf",
     "label": "History of congestive heart failure",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "cvd",
     "label": "Cerebrovascular disease (stroke or TIA)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "insulin",
     "label": "Diabetes treated with insulin",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    }
   ],
   "references": [
    {
     "title": "Lee TH et al. Derivation and prospective validation of a simple index for prediction of cardiac risk of major noncardiac surgery. Circulation 1999;100:1043–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10477528/"
    },
    {
     "title": "Duceppe E et al. Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery. Can J Cardiol 2017;33:17–32.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/27865641/"
    }
   ]
  },
  {
   "id": "geneva-revised",
   "name": "Revised Geneva Score for Pulmonary Embolism",
   "short": "Revised Geneva",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/geneva-revised/",
   "summary": "The revised Geneva score (0–25) estimates clinical probability of PE from objective items only: 0–3 low (~8% PE), 4–10 intermediate (~28%), ≥11 high (~74%).",
   "formula": "Age > 65: 1 · previous DVT/PE 3 · surgery or fracture ≤ 1 month 2 · active malignancy 2 · unilateral leg pain 3 · hemoptysis 2 · HR 75–94: 3, ≥ 95: 5 · deep-vein palpation pain + unilateral edema 4",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 300
    },
    {
     "id": "prior_vte",
     "label": "Previous DVT or PE",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "surgery",
     "label": "Surgery (general anesthesia) or lower-limb fracture within 1 month",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "cancer",
     "label": "Active malignancy (solid or hematologic, active or cured < 1 year)",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "leg_pain",
     "label": "Unilateral lower-limb pain",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "hemoptysis",
     "label": "Hemoptysis",
     "kind": "yn",
     "points": 2
    },
    {
     "id": "dvt_signs",
     "label": "Pain on deep venous palpation of lower limb and unilateral edema",
     "kind": "yn",
     "points": 4
    }
   ],
   "references": [
    {
     "title": "Le Gal G et al. Prediction of pulmonary embolism in the emergency department: the revised Geneva score. Ann Intern Med 2006;144:165–71.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16461960/"
    }
   ]
  },
  {
   "id": "r-ipi",
   "name": "Revised International Prognostic Index (R-IPI) for DLBCL",
   "short": "R-IPI",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/r-ipi/",
   "summary": "The R-IPI regroups the 5 IPI factors for DLBCL treated with R-CHOP: 0 factors = very good (4-year PFS 94%, OS 94%), 1–2 = good (PFS 80%, OS 79%), 3–5 = poor (PFS 53%, OS 55%).",
   "formula": "Count of IPI factors: age >60 · stage III/IV · LDH > ULN · ECOG ≥2 · >1 extranodal site. 0 very good · 1–2 good · 3–5 poor.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "stage",
     "label": "Ann Arbor stage",
     "kind": "sel",
     "options": [
      {
       "value": "I",
       "label": "Stage I"
      },
      {
       "value": "II",
       "label": "Stage II"
      },
      {
       "value": "III",
       "label": "Stage III"
      },
      {
       "value": "IV",
       "label": "Stage IV"
      }
     ]
    },
    {
     "id": "ldh_high",
     "label": "LDH above upper limit of normal",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "ecog",
     "label": "ECOG performance status",
     "kind": "sel",
     "options": [
      {
       "value": "0",
       "label": "ECOG 0"
      },
      {
       "value": "1",
       "label": "ECOG 1"
      },
      {
       "value": "2",
       "label": "ECOG 2"
      },
      {
       "value": "3",
       "label": "ECOG 3"
      },
      {
       "value": "4",
       "label": "ECOG 4"
      }
     ]
    },
    {
     "id": "extranodal",
     "label": "Number of extranodal sites",
     "kind": "num",
     "min": 0,
     "max": 20
    }
   ],
   "references": [
    {
     "title": "Sehn LH et al. The revised International Prognostic Index (R-IPI) is a better predictor of outcome than the standard IPI for patients with DLBCL treated with R-CHOP. Blood 2007;109:1857–61.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/17105812/"
    }
   ]
  },
  {
   "id": "revised-trauma-score",
   "name": "Revised Trauma Score (RTS)",
   "short": "RTS",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/revised-trauma-score/",
   "summary": "The Revised Trauma Score weights coded GCS, systolic BP and respiratory rate: RTS = 0.9368·GCSc + 0.7326·SBPc + 0.2908·RRc (0 to 7.84; lower is worse). The unweighted triage version (T-RTS, 0–12) sums the codes; T-RTS <12 is the usual threshold for trauma-centre triage.",
   "formula": "Codes: GCS 13–15→4, 9–12→3, 6–8→2, 4–5→1, 3→0 · SBP >89→4, 76–89→3, 50–75→2, 1–49→1, 0→0 · RR 10–29→4, >29→3, 6–9→2, 1–5→1, 0→0. RTS = 0.9368·GCSc + 0.7326·SBPc + 0.2908·RRc; T-RTS = GCSc + SBPc + RRc.",
   "inputs": [
    {
     "id": "gcs",
     "label": "Glasgow Coma Scale",
     "kind": "num",
     "min": 3,
     "max": 15
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 80
    }
   ],
   "references": [
    {
     "title": "Champion HR et al. A revision of the Trauma Score. J Trauma 1989;29:623–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/2657085/"
    }
   ]
  },
  {
   "id": "rochester-criteria",
   "name": "Rochester Criteria (Low-Risk Febrile Infant ≤ 60 days)",
   "short": "Rochester criteria",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/rochester-criteria/",
   "summary": "The Rochester criteria identify febrile infants ≤60 days at low risk for serious bacterial infection if well-appearing, previously healthy, without focal infection, with WBC 5–15 ×10⁹/L, bands ≤1.5 ×10⁹/L, ≤10 WBC/hpf in spun urine and ≤5 WBC/hpf in stool (if diarrhea). NPV for SBI 98.9%.",
   "formula": "Low risk if ALL: well-appearing; previously healthy; no skin/soft tissue/bone/joint/ear infection; WBC 5–15 ×10⁹/L; bands ≤ 1.5 ×10⁹/L; spun urine ≤ 10 WBC/hpf; stool ≤ 5 WBC/hpf if diarrhea",
   "inputs": [
    {
     "id": "ageDays",
     "label": "Age",
     "kind": "num",
     "min": 0,
     "max": 60
    },
    {
     "id": "wellAppearing",
     "label": "Appears generally well",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "previouslyHealthy",
     "label": "Previously healthy (term ≥37 wk, no perinatal antibiotics, no unexplained hyperbilirubinemia treatment, not hospitalized longer than mother, no chronic illness, no prior antibiotics/hospitalization)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "focalInfection",
     "label": "Evidence of skin, soft tissue, bone, joint or ear infection",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "wbc",
     "label": "Peripheral WBC",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 100
    },
    {
     "id": "bands",
     "label": "Absolute band count",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL",
      "/µL",
      "/mm³"
     ],
     "min": 0,
     "max": 50
    },
    {
     "id": "uaWbc",
     "label": "Urine WBC (spun sediment)",
     "kind": "num",
     "min": 0,
     "max": 500
    },
    {
     "id": "diarrhea",
     "label": "Diarrhea present",
     "kind": "yn",
     "points": 1,
     "optional": true
    },
    {
     "id": "stoolWbc",
     "label": "Stool WBC (if diarrhea)",
     "kind": "num",
     "min": 0,
     "max": 500,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Jaskiewicz JA et al. Febrile infants at low risk for serious bacterial infection: an appraisal of the Rochester criteria. Pediatrics 1994;94:390–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8065869/"
    },
    {
     "title": "Dagan R et al. Identification of infants unlikely to have serious bacterial infection although hospitalized for suspected sepsis. J Pediatr 1985;107:855–60.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/4067741/"
    }
   ]
  },
  {
   "id": "rockall-full",
   "name": "Rockall Score (Complete, Post-endoscopy)",
   "short": "Full Rockall",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/rockall-full/",
   "summary": "The complete Rockall score (0–11) adds endoscopic diagnosis and stigmata of recent haemorrhage to age, shock and comorbidity to predict rebleeding and death after upper GI bleeding. A score ≤2 indicates low risk (mortality ~0.1–0.2%).",
   "formula": "Pre-endoscopy Rockall (age, shock, comorbidity) + diagnosis (Mallory-Weiss/no lesion = 0, all other = 1, upper GI malignancy = 2) + SRH (none/dark spot = 0; blood, adherent clot, visible or spurting vessel = 2)",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 16,
     "max": 120
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 250
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "comorb",
     "label": "Comorbidity",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "No major comorbidity",
       "points": 0
      },
      {
       "value": "major",
       "label": "Cardiac failure, ischemic heart disease, or any major comorbidity",
       "points": 2
      },
      {
       "value": "severe",
       "label": "Renal failure, liver failure, or disseminated malignancy",
       "points": 3
      }
     ]
    },
    {
     "id": "dx",
     "label": "Endoscopic diagnosis",
     "kind": "sel",
     "options": [
      {
       "value": "mw",
       "label": "Mallory-Weiss tear, or no lesion and no SRH",
       "points": 0
      },
      {
       "value": "other",
       "label": "All other diagnoses (ulcer, erosions, varices, esophagitis)",
       "points": 1
      },
      {
       "value": "malig",
       "label": "Malignancy of upper GI tract",
       "points": 2
      }
     ]
    },
    {
     "id": "srh",
     "label": "Stigmata of recent haemorrhage",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None, or dark spot only",
       "points": 0
      },
      {
       "value": "major",
       "label": "Blood in upper GI tract, adherent clot, visible or spurting vessel",
       "points": 2
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Rockall TA et al. Risk assessment after acute upper gastrointestinal haemorrhage. Gut 1996;38:316–21.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8675081/"
    }
   ]
  },
  {
   "id": "rockall-pre",
   "name": "Rockall Score (Pre-endoscopy / Clinical)",
   "short": "Pre-endoscopy Rockall",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/rockall-pre/",
   "summary": "The pre-endoscopy (clinical) Rockall score (0–7) uses age, shock and comorbidity to estimate mortality in upper GI bleeding before endoscopy. A score of 0 identifies very low risk; it is completed after endoscopy as the full Rockall score.",
   "formula": "Age <60 = 0, 60–79 = 1, ≥80 = 2 · Shock: none (SBP ≥100, HR <100) = 0, tachycardia (HR ≥100, SBP ≥100) = 1, hypotension (SBP <100) = 2 · Comorbidity: none = 0, cardiac failure/IHD/any major = 2, renal failure/liver failure/disseminated malignancy = 3",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 16,
     "max": 120
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 250
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "comorb",
     "label": "Comorbidity",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "No major comorbidity",
       "points": 0
      },
      {
       "value": "major",
       "label": "Cardiac failure, ischemic heart disease, or any major comorbidity",
       "points": 2
      },
      {
       "value": "severe",
       "label": "Renal failure, liver failure, or disseminated malignancy",
       "points": 3
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Rockall TA et al. Risk assessment after acute upper gastrointestinal haemorrhage. Gut 1996;38:316–21.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8675081/"
    }
   ]
  },
  {
   "id": "rox-index",
   "name": "ROX Index for High-Flow Nasal Cannula",
   "short": "ROX",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/rox-index/",
   "summary": "The ROX index = (SpO₂ / FiO₂) / respiratory rate predicts high-flow nasal cannula (HFNC) outcome in acute hypoxemic respiratory failure. ROX ≥4.88 at 2, 6 or 12 hours predicts HFNC success; values <2.85 (2 h), <3.47 (6 h) or <3.85 (12 h) predict HFNC failure and need for intubation.",
   "formula": "ROX = (SpO₂ % ÷ FiO₂ fraction) ÷ respiratory rate",
   "inputs": [
    {
     "id": "spo2",
     "label": "SpO₂",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 40,
     "max": 100
    },
    {
     "id": "fio2",
     "label": "FiO₂ (% or fraction)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0.21,
     "max": 100
    },
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 80
    },
    {
     "id": "hours",
     "label": "Time on HFNC",
     "kind": "sel",
     "options": [
      {
       "value": "2",
       "label": "2 hours"
      },
      {
       "value": "6",
       "label": "6 hours"
      },
      {
       "value": "12",
       "label": "12 hours"
      }
     ],
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Roca O et al. An index combining respiratory rate and oxygenation to predict outcome of nasal high-flow therapy. Am J Respir Crit Care Med 2019;199:1368–76.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/30576221/"
    }
   ]
  },
  {
   "id": "rule-of-nines",
   "name": "Rule of Nines (Adult Burn TBSA)",
   "short": "Rule of nines",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/rule-of-nines/",
   "summary": "Wallace rule of nines estimates adult burn size: head/neck 9%, each arm 9%, anterior trunk 18%, posterior trunk 18%, each leg 18%, perineum 1%. Count only partial- and full-thickness burns. ≥20% TBSA in adults generally needs formal IV fluid resuscitation; >10% partial-thickness meets burn-centre referral criteria.",
   "formula": "TBSA % = sum of fully burned regions: head/neck 9 · each upper limb 9 · anterior trunk 18 · posterior trunk 18 · each lower limb 18 · perineum 1, plus any extra % (patient palm with fingers ≈ 1%).",
   "inputs": [
    {
     "id": "head",
     "label": "Head and neck (9%)",
     "kind": "yn",
     "points": 9
    },
    {
     "id": "arm_r",
     "label": "Right upper limb (9%)",
     "kind": "yn",
     "points": 9
    },
    {
     "id": "arm_l",
     "label": "Left upper limb (9%)",
     "kind": "yn",
     "points": 9
    },
    {
     "id": "trunk_ant",
     "label": "Anterior trunk: chest + abdomen (18%)",
     "kind": "yn",
     "points": 18
    },
    {
     "id": "trunk_post",
     "label": "Posterior trunk: back + buttocks (18%)",
     "kind": "yn",
     "points": 18
    },
    {
     "id": "leg_r",
     "label": "Right lower limb (18%)",
     "kind": "yn",
     "points": 18
    },
    {
     "id": "leg_l",
     "label": "Left lower limb (18%)",
     "kind": "yn",
     "points": 18
    },
    {
     "id": "perineum",
     "label": "Perineum / genitalia (1%)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "extra_pct",
     "label": "Additional scattered burns, % (patient palm ≈ 1%)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0,
     "max": 100,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Wallace AB. The exposure treatment of burns. Lancet 1951;1:501–4.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/14805109/"
    }
   ]
  },
  {
   "id": "sf-syncope",
   "name": "San Francisco Syncope Rule",
   "short": "SF Syncope Rule",
   "category": "Emergency & Trauma",
   "url": "https://askcalc.site/calc/sf-syncope/",
   "summary": "The San Francisco Syncope Rule (CHESS) flags ED syncope patients at risk of a serious outcome within 7 days if any is present: history of CHF, hematocrit <30%, abnormal ECG, shortness of breath, or triage SBP <90 mmHg. Derivation sensitivity 96%, specificity 62%.",
   "formula": "C: history of CHF · H: Hct <30% · E: abnormal ECG (non-sinus rhythm or new changes) · S: shortness of breath · S: triage SBP <90 mmHg. Any = not low risk.",
   "inputs": [
    {
     "id": "chf",
     "label": "History of congestive heart failure",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "hct",
     "label": "Hematocrit",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 5,
     "max": 75
    },
    {
     "id": "ecg",
     "label": "Abnormal ECG (non-sinus rhythm or new changes)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "sob",
     "label": "Shortness of breath",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "sbp",
     "label": "Triage systolic BP",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 0,
     "max": 300
    }
   ],
   "references": [
    {
     "title": "Quinn JV et al. Derivation of the San Francisco Syncope Rule to predict patients with short-term serious outcomes. Ann Emerg Med 2004;43:224–32.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/14747812/"
    }
   ]
  },
  {
   "id": "sens-spec",
   "name": "Sensitivity, Specificity, PPV, NPV from a 2×2 Table",
   "short": "2×2 diagnostic stats",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/sens-spec/",
   "summary": "From a 2×2 table of true positives (TP), false positives (FP), false negatives (FN) and true negatives (TN): sensitivity = TP/(TP+FN), specificity = TN/(TN+FP), PPV = TP/(TP+FP), NPV = TN/(TN+FN), LR+ = sens/(1 − spec), LR− = (1 − sens)/spec.",
   "formula": "Sens = TP/(TP+FN) · Spec = TN/(TN+FP) · PPV = TP/(TP+FP) · NPV = TN/(TN+FN) · LR+ = sens/(1−spec) · LR− = (1−sens)/spec · Prevalence = (TP+FN)/N · Accuracy = (TP+TN)/N",
   "inputs": [
    {
     "id": "tp",
     "label": "True positives (TP)",
     "kind": "num",
     "min": 0,
     "max": 1000000000
    },
    {
     "id": "fp",
     "label": "False positives (FP)",
     "kind": "num",
     "min": 0,
     "max": 1000000000
    },
    {
     "id": "fn",
     "label": "False negatives (FN)",
     "kind": "num",
     "min": 0,
     "max": 1000000000
    },
    {
     "id": "tn",
     "label": "True negatives (TN)",
     "kind": "num",
     "min": 0,
     "max": 1000000000
    }
   ],
   "references": [
    {
     "title": "Altman DG, Bland JM. Diagnostic tests 1: sensitivity and specificity. BMJ 1994;308:1552.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8019315/"
    },
    {
     "title": "Altman DG, Bland JM. Diagnostic tests 2: predictive values. BMJ 1994;309:102.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8038641/"
    }
   ]
  },
  {
   "id": "anion-gap",
   "name": "Serum Anion Gap (with Albumin Correction)",
   "short": "Anion gap",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/anion-gap/",
   "summary": "Anion gap = Na − (Cl + HCO₃). A typical normal value is about 8–12 mmol/L (lab-dependent, often lower with modern analysers); higher suggests a high-anion-gap metabolic acidosis. Each 1 g/dL (10 g/L) fall in albumin lowers the gap by about 2.5, so correct for hypoalbuminaemia.",
   "formula": "AG = Na⁺ − (Cl⁻ + HCO₃⁻). Albumin-corrected AG = AG + 2.5 × (4.0 − albumin g/dL) = AG + 0.25 × (40 − albumin g/L).",
   "inputs": [
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "cl",
     "label": "Serum chloride",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 60,
     "max": 150
    },
    {
     "id": "hco3",
     "label": "Serum bicarbonate (HCO₃⁻)",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 60
    },
    {
     "id": "albumin",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 6.5,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Emmett M, Narins RG. Clinical use of the anion gap. Medicine (Baltimore) 1977;56:38–54.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/401925/"
    },
    {
     "title": "Figge J et al. Anion gap and hypoalbuminemia. Crit Care Med 1998;26:1807–10.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9824071/"
    }
   ]
  },
  {
   "id": "osmolal-gap",
   "name": "Serum Osmolal Gap",
   "short": "Osmolal gap",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/osmolal-gap/",
   "summary": "Osmolal gap = measured osmolality − (2 × Na + glucose/18 + BUN/2.8 [+ ethanol/3.7]). A gap above about 10 mOsm/kg suggests unmeasured osmoles such as methanol, ethylene glycol or isopropanol; a normal gap does not exclude toxic alcohol ingestion.",
   "formula": "OG = measured Osm − [2 × Na⁺ + glucose (mg/dL)/18 + BUN (mg/dL)/2.8 + ethanol (mg/dL)/3.7]. SI: 2Na + glucose + urea + 1.25 × ethanol (mmol/L).",
   "inputs": [
    {
     "id": "osm",
     "label": "Measured serum osmolality",
     "kind": "num",
     "min": 200,
     "max": 500
    },
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "glucose",
     "label": "Serum glucose",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 10,
     "max": 3000
    },
    {
     "id": "bun",
     "label": "BUN / serum urea",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "etoh",
     "label": "Serum ethanol",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 0,
     "max": 1000,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Purssell RA et al. Derivation and validation of a formula to calculate the contribution of ethanol to the osmolal gap. Ann Emerg Med 2001;38:653–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11719745/"
    },
    {
     "title": "Dorwart WV, Chalmers L. Comparison of methods for calculating serum osmolality from chemical concentrations. Clin Chem 1975;21:190–4.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1112025/"
    }
   ]
  },
  {
   "id": "saag",
   "name": "Serum-Ascites Albumin Gradient (SAAG)",
   "short": "SAAG",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/saag/",
   "summary": "SAAG = serum albumin − ascitic fluid albumin (same day). A SAAG ≥1.1 g/dL indicates portal hypertension (cirrhosis, heart failure, Budd-Chiari) with about 97% accuracy; <1.1 g/dL suggests non-portal causes (peritoneal carcinomatosis, TB, pancreatitis, nephrotic syndrome).",
   "formula": "SAAG = serum albumin − ascitic fluid albumin (g/dL), samples drawn the same day",
   "inputs": [
    {
     "id": "salb",
     "label": "Serum albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0.5,
     "max": 6.5
    },
    {
     "id": "aalb",
     "label": "Ascitic fluid albumin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 0,
     "max": 6
    }
   ],
   "references": [
    {
     "title": "Runyon BA et al. The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites. Ann Intern Med 1992;117:215–20.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1616215/"
    }
   ]
  },
  {
   "id": "sgarbossa",
   "name": "Sgarbossa Criteria (Original and Smith-Modified) for MI in LBBB",
   "short": "Sgarbossa",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/sgarbossa/",
   "summary": "Sgarbossa criteria identify acute MI in left bundle branch block. Original (1996): concordant STE ≥1 mm (5), concordant STD ≥1 mm in V1–V3 (3), discordant STE ≥5 mm (2); ≥3 points is highly specific. Smith-modified (2012) replaces the 5 mm rule with discordant STE ≥25% of the preceding S-wave depth (ST/S ≤ −0.25); any one criterion is positive (sensitivity 91%, specificity 90%).",
   "formula": "Original: concordant STE ≥1 mm in any lead = 5 · concordant STD ≥1 mm in V1–V3 = 3 · discordant STE ≥5 mm = 2; positive if ≥3. Smith-modified (unweighted): concordant STE ≥1 mm, OR concordant STD ≥1 mm in V1–V3, OR discordant STE with ST/S ratio ≤ −0.25 (STE ≥25% of preceding S depth) in any lead; positive if ≥1.",
   "inputs": [
    {
     "id": "version",
     "label": "Criteria version",
     "kind": "sel",
     "options": [
      {
       "value": "smith",
       "label": "Smith-modified (2012)"
      },
      {
       "value": "original",
       "label": "Original Sgarbossa (1996)"
      }
     ],
     "optional": true
    },
    {
     "id": "concordant_ste",
     "label": "Concordant ST elevation ≥1 mm in any lead",
     "kind": "yn",
     "points": 5
    },
    {
     "id": "concordant_std",
     "label": "Concordant ST depression ≥1 mm in V1, V2 or V3",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "discordant_5mm",
     "label": "Discordant ST elevation ≥5 mm (original criterion)",
     "kind": "yn",
     "points": 2,
     "optional": true
    },
    {
     "id": "discordant_ratio",
     "label": "Discordant ST elevation ≥25% of S-wave depth, ST/S ≤ −0.25 (Smith criterion)",
     "kind": "yn",
     "points": 1,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Sgarbossa EB et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. N Engl J Med 1996;334:481–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8559200/"
    },
    {
     "title": "Smith SW et al. Diagnosis of ST-elevation myocardial infarction in the presence of left bundle branch block with the ST-elevation to S-wave ratio in a modified Sgarbossa rule. Ann Emerg Med 2012;60:766–76.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/22939607/"
    }
   ]
  },
  {
   "id": "shock-index",
   "name": "Shock Index",
   "short": "Shock index",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/shock-index/",
   "summary": "Shock index is heart rate divided by systolic blood pressure. Normal is about 0.5–0.7; ≥1.0 suggests significant hypovolemia or shock and predicts transfusion need and mortality in trauma, sepsis and bleeding.",
   "formula": "Shock index = heart rate (bpm) ÷ systolic blood pressure (mmHg)",
   "inputs": [
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 300
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    }
   ],
   "references": [
    {
     "title": "Allgöwer M, Burri C. [\"Shock index\"]. Dtsch Med Wochenschr 1967;92:1947–50.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/5299769/"
    }
   ]
  },
  {
   "id": "sdai-ra",
   "name": "Simplified Disease Activity Index (SDAI) for Rheumatoid Arthritis",
   "short": "SDAI",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/sdai-ra/",
   "summary": "The SDAI is the sum of 28-joint tender and swollen counts, patient and evaluator global assessments (0–10) and CRP in mg/dL. Remission ≤3.3, low ≤11, moderate ≤26, high >26.",
   "formula": "SDAI = TJC28 + SJC28 + patient global (0–10) + evaluator global (0–10) + CRP (mg/dL). Enter CRP in mg/L or mg/dL; it is converted to mg/dL (mg/L ÷ 10).",
   "inputs": [
    {
     "id": "tjc",
     "label": "Tender joint count (28 joints)",
     "kind": "num",
     "unit": "joints",
     "units": [
      "joints"
     ],
     "min": 0,
     "max": 28
    },
    {
     "id": "sjc",
     "label": "Swollen joint count (28 joints)",
     "kind": "num",
     "unit": "joints",
     "units": [
      "joints"
     ],
     "min": 0,
     "max": 28
    },
    {
     "id": "ptga",
     "label": "Patient global assessment of disease activity (0–10)",
     "kind": "num",
     "min": 0,
     "max": 10
    },
    {
     "id": "ega",
     "label": "Evaluator (physician) global assessment of disease activity (0–10)",
     "kind": "num",
     "min": 0,
     "max": 10
    },
    {
     "id": "crp",
     "label": "C-reactive protein",
     "kind": "num",
     "unit": "mg/L",
     "units": [
      "mg/L",
      "mg/dL"
     ],
     "min": 0,
     "max": 500
    }
   ],
   "references": [
    {
     "title": "Smolen JS et al. A simplified disease activity index for rheumatoid arthritis for use in clinical practice. Rheumatology (Oxford) 2003;42:244–57.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/12595618/"
    },
    {
     "title": "Aletaha D, Smolen J. The SDAI and the CDAI: a review of their usefulness and validity in rheumatoid arthritis. Clin Exp Rheumatol 2005;23(5 Suppl 39):S100–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/16273793/"
    }
   ]
  },
  {
   "id": "spesi",
   "name": "Simplified Pulmonary Embolism Severity Index (sPESI)",
   "short": "sPESI",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/spesi/",
   "summary": "sPESI scores 1 point each for age >80, cancer, chronic cardiopulmonary disease, HR ≥110, SBP <100 and SaO₂ <90%. A score of 0 is low risk (30-day mortality ~1.0%); ≥1 is high risk (~10.9%).",
   "formula": "One point each: age > 80 · cancer · chronic cardiopulmonary disease · HR ≥ 110 · SBP < 100 · SaO₂ < 90%",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "cancer",
     "label": "Active cancer",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "cardiopulm",
     "label": "Chronic cardiopulmonary disease (heart failure or chronic lung disease)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 300
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "spo2",
     "label": "Arterial oxygen saturation (SaO₂)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 40,
     "max": 100
    }
   ],
   "references": [
    {
     "title": "Jiménez D et al. Simplification of the pulmonary embolism severity index for prognostication in patients with acute symptomatic pulmonary embolism. Arch Intern Med 2010;170:1383–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/20696966/"
    }
   ]
  },
  {
   "id": "sirs",
   "name": "SIRS Criteria (Systemic Inflammatory Response Syndrome)",
   "short": "SIRS",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/sirs/",
   "summary": "SIRS is present when ≥2 of 4 criteria are met: temperature >38 °C or <36 °C, heart rate >90, respiratory rate >20 or PaCO₂ <32 mmHg, and WBC >12 or <4 ×10⁹/L or >10% bands. SIRS plus suspected infection was the 1992 (Sepsis-1) definition of sepsis.",
   "formula": "Count: T >38 or <36 °C · HR >90 · RR >20 or PaCO₂ <32 mmHg · WBC >12 or <4 ×10⁹/L or >10% bands. SIRS = ≥2.",
   "inputs": [
    {
     "id": "temp",
     "label": "Temperature",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 20,
     "max": 45
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "rr",
     "label": "Respiratory rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 0,
     "max": 80
    },
    {
     "id": "paco2",
     "label": "PaCO₂ (arterial)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 5,
     "max": 200,
     "optional": true
    },
    {
     "id": "wbc",
     "label": "WBC",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 500
    },
    {
     "id": "bands",
     "label": "Bands >10%",
     "kind": "yn",
     "points": 1,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Bone RC et al. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis (ACCP/SCCM Consensus Conference). Chest 1992;101:1644–55.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1303622/"
    }
   ]
  },
  {
   "id": "sodium-correction",
   "name": "Sodium Change per Litre of Infusate (Adrogué–Madias)",
   "short": "ΔNa per litre",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/sodium-correction/",
   "summary": "The Adrogué–Madias formula estimates the change in serum sodium after 1 L of a fluid: (infusate Na + K − serum Na) ÷ (total body water + 1). In chronic hyponatraemia limit correction to ~8 mmol/L in 24 h in high-risk patients and never exceed 10–12 mmol/L, to avoid osmotic demyelination.",
   "formula": "ΔNa (per 1 L) = (infusate Na⁺ + infusate K⁺ − serum Na⁺) ÷ (TBW + 1). TBW = weight × 0.6 (children, men <65), 0.5 (women <65, men ≥65), 0.45 (women ≥65).",
   "inputs": [
    {
     "id": "na",
     "label": "Serum sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 90,
     "max": 200
    },
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "fluid",
     "label": "Infusate",
     "kind": "sel",
     "options": [
      {
       "value": "ns5",
       "label": "5% NaCl (Na 855)"
      },
      {
       "value": "ns3",
       "label": "3% NaCl (Na 513)"
      },
      {
       "value": "ns",
       "label": "0.9% NaCl (Na 154)"
      },
      {
       "value": "pl",
       "label": "Plasma-Lyte 148 (Na 140, K 5)"
      },
      {
       "value": "rl",
       "label": "Ringer's lactate (Na 130, K 4)"
      },
      {
       "value": "hns",
       "label": "0.45% NaCl (Na 77)"
      },
      {
       "value": "qns",
       "label": "0.2% NaCl in D5W (Na 34)"
      },
      {
       "value": "d5w",
       "label": "D5W / free water (Na 0)"
      }
     ]
    },
    {
     "id": "kadd",
     "label": "Added potassium in infusate",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 0,
     "max": 80,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med 2000;342:1581–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10824078/"
    },
    {
     "title": "Adrogué HJ, Madias NE. Hypernatremia. N Engl J Med 2000;342:1493–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10816188/"
    },
    {
     "title": "Verbalis JG et al. Diagnosis, evaluation, and treatment of hyponatremia: expert panel recommendations. Am J Med 2013;126(10 Suppl 1):S1–42.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/24074529/"
    }
   ]
  },
  {
   "id": "sofa",
   "name": "SOFA Score (Sequential Organ Failure Assessment)",
   "short": "SOFA",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/sofa/",
   "summary": "SOFA scores dysfunction of six organ systems (respiratory, coagulation, liver, cardiovascular, CNS, renal) from 0 to 4 each, total 0–24. Under Sepsis-3, an acute rise of ≥2 points from baseline in a patient with infection defines sepsis; higher totals carry higher ICU mortality.",
   "formula": "Respiratory PaO₂/FiO₂: ≥400 0, <400 1, <300 2, <200 with support 3, <100 with support 4 · Platelets ×10³/µL: ≥150 0, <150 1, <100 2, <50 3, <20 4 · Bilirubin mg/dL: <1.2 0, 1.2–1.9 1, 2.0–5.9 2, 6.0–11.9 3, ≥12 4 · CV: MAP ≥70 0, MAP <70 1, dopamine ≤5 or dobutamine 2, dopamine >5 or epi/norepi ≤0.1 3, dopamine >15 or epi/norepi >0.1 4 · GCS: 15 0, 13–14 1, 10–12 2, 6–9 3, <6 4 · Creatinine mg/dL: <1.2 0, 1.2–1.9 1, 2.0–3.4 2, 3.5–4.9 or UO <500 mL/d 3, ≥5 or UO <200 mL/d 4",
   "inputs": [
    {
     "id": "pao2",
     "label": "PaO₂ (arterial)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 700
    },
    {
     "id": "fio2",
     "label": "FiO₂ (% or fraction)",
     "kind": "num",
     "unit": "%",
     "units": [
      "%"
     ],
     "min": 0.21,
     "max": 100
    },
    {
     "id": "vent",
     "label": "On mechanical ventilation / respiratory support",
     "kind": "yn",
     "points": 0
    },
    {
     "id": "plt",
     "label": "Platelets",
     "kind": "num",
     "unit": "×10⁹/L",
     "units": [
      "×10⁹/L",
      "×10³/µL"
     ],
     "min": 0,
     "max": 2000
    },
    {
     "id": "bili",
     "label": "Total bilirubin",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0,
     "max": 60
    },
    {
     "id": "map",
     "label": "Mean arterial pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 10,
     "max": 200
    },
    {
     "id": "pressor",
     "label": "Vasopressors (µg/kg/min, ≥1 h)",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "dopa_low",
       "label": "Dopamine ≤5 or any dobutamine",
       "points": 2
      },
      {
       "value": "mid",
       "label": "Dopamine >5, or epinephrine ≤0.1, or norepinephrine ≤0.1",
       "points": 3
      },
      {
       "value": "high",
       "label": "Dopamine >15, or epinephrine >0.1, or norepinephrine >0.1",
       "points": 4
      }
     ]
    },
    {
     "id": "gcs",
     "label": "Glasgow Coma Scale",
     "kind": "num",
     "min": 3,
     "max": 15
    },
    {
     "id": "creat",
     "label": "Serum creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L"
     ],
     "min": 0.1,
     "max": 25
    },
    {
     "id": "uo",
     "label": "Urine output (mL/day)",
     "kind": "num",
     "min": 0,
     "max": 15000,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Vincent JL et al. The SOFA (Sepsis-related Organ Failure Assessment) score to describe organ dysfunction/failure. Intensive Care Med 1996;22:707–10.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8844239/"
    },
    {
     "title": "Singer M et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA 2016;315:801–10.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/26903338/"
    }
   ]
  },
  {
   "id": "spetzler-martin",
   "name": "Spetzler-Martin Grade for Brain AVM",
   "short": "Spetzler-Martin",
   "category": "Neurology",
   "url": "https://askcalc.site/calc/spetzler-martin/",
   "summary": "The Spetzler-Martin grade (I–V) estimates surgical risk for brain AVMs: nidus size (<3 cm 1, 3–6 cm 2, >6 cm 3) + eloquent location (1) + deep venous drainage (1). Spetzler-Ponce classes: A (I–II) surgery, B (III) multimodality, C (IV–V) generally observation.",
   "formula": "Size: <3 cm 1 · 3–6 cm 2 · >6 cm 3. Eloquent location: 1. Deep venous drainage: 1. Grade = sum (I–V).",
   "inputs": [
    {
     "id": "size",
     "label": "Maximum nidus diameter",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 0.1,
     "max": 15
    },
    {
     "id": "eloquent",
     "label": "Eloquent adjacent brain",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "deep",
     "label": "Deep venous drainage",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Spetzler RF, Martin NA. A proposed grading system for arteriovenous malformations. J Neurosurg 1986;65:476–83.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3760956/"
    },
    {
     "title": "Spetzler RF, Ponce FA. A 3-tier classification of cerebral arteriovenous malformations. J Neurosurg 2011;114:842–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/20932095/"
    }
   ]
  },
  {
   "id": "stool-osmotic-gap",
   "name": "Stool Osmotic Gap",
   "short": "Stool osmotic gap",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/stool-osmotic-gap/",
   "summary": "Stool osmotic gap = 290 − 2 × (stool Na + stool K). A gap >125 mOsm/kg suggests osmotic diarrhoea (e.g. magnesium, lactose, sorbitol); <50 mOsm/kg suggests secretory diarrhoea.",
   "formula": "Stool osmotic gap = 290 − 2 × (stool Na⁺ + stool K⁺)",
   "inputs": [
    {
     "id": "sna",
     "label": "Stool sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 0,
     "max": 200
    },
    {
     "id": "sk",
     "label": "Stool potassium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 0,
     "max": 200
    }
   ],
   "references": [
    {
     "title": "Eherer AJ, Fordtran JS. Fecal osmotic gap and pH in experimental diarrhea of various causes. Gastroenterology 1992;103:545–51.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1634072/"
    }
   ]
  },
  {
   "id": "stop-bang",
   "name": "STOP-Bang Questionnaire for Obstructive Sleep Apnea",
   "short": "STOP-Bang",
   "category": "Pulmonary & Critical Care",
   "url": "https://askcalc.site/calc/stop-bang/",
   "summary": "STOP-Bang screens for obstructive sleep apnea with 8 yes/no items: Snoring, Tiredness, Observed apnea, high blood Pressure, BMI >35, Age >50, Neck circumference >40 cm, male Gender. 0–2 is low risk, 3–4 intermediate and 5–8 high risk; 2+ STOP items plus male sex, BMI >35 or neck >40 cm also indicates high risk.",
   "formula": "One point each: Snoring · Tired · Observed apnea · Pressure (HTN) · BMI >35 · Age >50 · Neck >40 cm · male Gender",
   "inputs": [
    {
     "id": "snore",
     "label": "Snores loudly",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "tired",
     "label": "Tired, fatigued or sleepy during the day",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "observed",
     "label": "Observed apneas or choking/gasping during sleep",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "pressure",
     "label": "High blood pressure (treated or untreated)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "bmi35",
     "label": "BMI >35 kg/m²",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "neck",
     "label": "Neck circumference >40 cm",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Chung F et al. STOP questionnaire: a tool to screen patients for obstructive sleep apnea. Anesthesiology 2008;108:812–21.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/18431116/"
    },
    {
     "title": "Chung F, Abdullah HR, Liao P. STOP-Bang questionnaire: a practical approach to screen for obstructive sleep apnea. Chest 2016;149:631–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/26378880/"
    }
   ]
  },
  {
   "id": "target-weight",
   "name": "Target Weight for a Target BMI",
   "short": "Target weight",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/target-weight/",
   "summary": "Target weight = target BMI × height (m)². For example, a BMI of 25 at 1.75 m is 76.6 kg. Add current weight to see how many kilograms must be lost or gained.",
   "formula": "Target weight (kg) = target BMI × height (m)²",
   "inputs": [
    {
     "id": "tbmi",
     "label": "Target BMI",
     "kind": "num",
     "min": 12,
     "max": 60
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 30,
     "max": 250
    },
    {
     "id": "weight",
     "label": "Current weight (optional)",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 0.3,
     "max": 400,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "MedCalc-Bench reference implementation (target_weight.py).",
     "url": "https://github.com/ncbi-nlp/MedCalc-Bench/tree/main/calculator_implementations"
    },
    {
     "title": "WHO. Obesity: preventing and managing the global epidemic. Technical Report Series 894 (2000).",
     "url": "https://iris.who.int/handle/10665/42330"
    }
   ]
  },
  {
   "id": "temperature-conversion",
   "name": "Temperature Conversion (°C ↔ °F)",
   "short": "°C ↔ °F",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/temperature-conversion/",
   "summary": "Converts body temperature between Celsius and Fahrenheit: °C = (°F − 32) × 5/9 and °F = °C × 9/5 + 32. Normal is about 37 °C (98.6 °F); fever is ≥38 °C (100.4 °F).",
   "formula": "°C = (°F − 32) × 5/9   ·   °F = °C × 9/5 + 32",
   "inputs": [
    {
     "id": "temp",
     "label": "Temperature",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 0,
     "max": 50
    }
   ],
   "references": [
    {
     "title": "MedCalc-Bench reference implementation (convert_temperature.py).",
     "url": "https://github.com/ncbi-nlp/MedCalc-Bench/tree/main/calculator_implementations"
    },
    {
     "title": "Mackowiak PA et al. A critical appraisal of 98.6°F, the upper limit of the normal body temperature. JAMA 1992;268:1578–80.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/1302471/"
    }
   ]
  },
  {
   "id": "timi-stemi",
   "name": "TIMI Risk Score for STEMI",
   "short": "TIMI STEMI",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/timi-stemi/",
   "summary": "The TIMI STEMI score (0–14) estimates 30-day mortality after ST-elevation MI, from 0.8% at 0 points to 35.9% at >8 points, using age, comorbidities, SBP, heart rate, Killip class, weight, anterior STE/LBBB and time to treatment.",
   "formula": "Age 65–74: 2, ≥ 75: 3 · DM/HTN/angina 1 · SBP < 100: 3 · HR > 100: 2 · Killip II–IV: 2 · weight < 67 kg: 1 · anterior STE or LBBB: 1 · time to treatment > 4 h: 1",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "dm_htn_angina",
     "label": "History of diabetes, hypertension or angina",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "sbp",
     "label": "Systolic blood pressure",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 30,
     "max": 300
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 300
    },
    {
     "id": "killip",
     "label": "Killip class",
     "kind": "sel",
     "options": [
      {
       "value": "I",
       "label": "I: no heart failure",
       "points": 0
      },
      {
       "value": "II",
       "label": "II: rales/crackles, S3 or JVP raised",
       "points": 2
      },
      {
       "value": "III",
       "label": "III: pulmonary edema",
       "points": 2
      },
      {
       "value": "IV",
       "label": "IV: cardiogenic shock",
       "points": 2
      }
     ]
    },
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 25,
     "max": 400
    },
    {
     "id": "anterior",
     "label": "Anterior ST elevation or LBBB",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "delay",
     "label": "Time to treatment > 4 hours",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Morrow DA et al. TIMI risk score for ST-elevation myocardial infarction. Circulation 2000;102:2031–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11044416/"
    }
   ]
  },
  {
   "id": "timi-ua-nstemi",
   "name": "TIMI Risk Score for UA/NSTEMI",
   "short": "TIMI UA/NSTEMI",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/timi-ua-nstemi/",
   "summary": "The TIMI score for unstable angina/NSTEMI (0–7) predicts 14-day all-cause death, new/recurrent MI or urgent revascularization, from 4.7% (score 0–1) to 40.9% (score 6–7). Scores ≥3 favour an early invasive strategy.",
   "formula": "One point each: age ≥ 65 · ≥ 3 CAD risk factors · known CAD (stenosis ≥ 50%) · aspirin in past 7 days · ≥ 2 anginal episodes in 24 h · ST deviation ≥ 0.5 mm · elevated cardiac markers",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 0,
     "max": 120
    },
    {
     "id": "rf3",
     "label": "≥ 3 CAD risk factors (family history, HTN, hypercholesterolemia, DM, current smoker)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "known_cad",
     "label": "Known CAD (stenosis ≥ 50%)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "asa",
     "label": "Aspirin use in the past 7 days",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "angina",
     "label": "Severe angina (≥ 2 episodes in 24 h)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "st",
     "label": "ST deviation ≥ 0.5 mm",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "markers",
     "label": "Elevated cardiac markers",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Antman EM et al. The TIMI risk score for unstable angina/non-ST elevation MI. JAMA 2000;284:835–42.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10938172/"
    }
   ]
  },
  {
   "id": "total-body-water-watson",
   "name": "Total Body Water (Watson Formula)",
   "short": "TBW (Watson)",
   "category": "General & Anthropometrics",
   "url": "https://askcalc.site/calc/total-body-water-watson/",
   "summary": "The Watson formula estimates total body water from sex, age, height and weight (men: 2.447 − 0.09516·age + 0.1074·height + 0.3362·weight; women: −2.097 + 0.1069·height + 0.2466·weight). It is commonly used as the urea distribution volume V in dialysis Kt/V.",
   "formula": "Men: TBW = 2.447 − 0.09516 × age + 0.1074 × height (cm) + 0.3362 × weight (kg). Women: TBW = −2.097 + 0.1069 × height + 0.2466 × weight.",
   "inputs": [
    {
     "id": "age",
     "label": "Age",
     "kind": "num",
     "unit": "years",
     "units": [
      "years"
     ],
     "min": 18,
     "max": 120
    },
    {
     "id": "sex",
     "label": "Sex",
     "kind": "sel",
     "options": [
      {
       "value": "male",
       "label": "Male"
      },
      {
       "value": "female",
       "label": "Female"
      }
     ]
    },
    {
     "id": "height",
     "label": "Height",
     "kind": "num",
     "unit": "cm",
     "units": [
      "cm",
      "m",
      "in"
     ],
     "min": 30,
     "max": 250
    },
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 0.3,
     "max": 400
    }
   ],
   "references": [
    {
     "title": "Watson PE, Watson ID, Batt RD. Total body water volumes for adult males and females estimated from simple anthropometric measurements. Am J Clin Nutr 1980;33:27–39.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/6986753/"
    }
   ]
  },
  {
   "id": "transferrin-saturation",
   "name": "Transferrin Saturation (TSAT)",
   "short": "TSAT",
   "category": "Hematology & Oncology",
   "url": "https://askcalc.site/calc/transferrin-saturation/",
   "summary": "Transferrin saturation = serum iron ÷ TIBC × 100. Normal is roughly 20–45%; <20% supports iron deficiency (absolute or functional), and a fasting value ≥45% warrants evaluation for iron overload (HFE haemochromatosis).",
   "formula": "TSAT (%) = serum iron ÷ TIBC × 100 (same units). If only transferrin (mg/dL) is available: TIBC (µg/dL) ≈ transferrin × 1.25.",
   "inputs": [
    {
     "id": "iron",
     "label": "Serum iron",
     "kind": "num",
     "unit": "µg/dL",
     "units": [
      "µg/dL",
      "µmol/L"
     ],
     "min": 1,
     "max": 1000
    },
    {
     "id": "tibc",
     "label": "Total iron-binding capacity (TIBC)",
     "kind": "num",
     "unit": "µg/dL",
     "units": [
      "µg/dL",
      "µmol/L"
     ],
     "min": 50,
     "max": 1000
    }
   ],
   "references": [
    {
     "title": "Bacon BR et al. Diagnosis and management of hemochromatosis: 2011 practice guideline by the AASLD. Hepatology 2011;54:328–43.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/21452290/"
    }
   ]
  },
  {
   "id": "ttkg",
   "name": "Transtubular Potassium Gradient (TTKG)",
   "short": "TTKG",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/ttkg/",
   "summary": "TTKG = (urine K ÷ plasma K) × (plasma osm ÷ urine osm), an index of distal potassium secretion. In hyperkalaemia a TTKG <7 suggests inadequate aldosterone effect; in hypokalaemia a TTKG <3 suggests extrarenal loss and >7 renal loss. Valid only if urine osm exceeds plasma osm.",
   "formula": "TTKG = (U_K ÷ P_K) × (P_osm ÷ U_osm). Valid when U_osm > P_osm and urine Na > 25 mmol/L.",
   "inputs": [
    {
     "id": "uk",
     "label": "Urine potassium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 300
    },
    {
     "id": "k",
     "label": "Plasma potassium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 10
    },
    {
     "id": "uosm",
     "label": "Urine osmolality",
     "kind": "num",
     "min": 50,
     "max": 1500
    },
    {
     "id": "posm",
     "label": "Plasma osmolality",
     "kind": "num",
     "min": 200,
     "max": 400
    }
   ],
   "references": [
    {
     "title": "Ethier JH et al. The transtubular potassium concentration in patients with hypokalemia and hyperkalemia. Am J Kidney Dis 1990;15:309–15.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/2321642/"
    }
   ]
  },
  {
   "id": "truelove-witts",
   "name": "Truelove and Witts Criteria (Ulcerative Colitis Severity)",
   "short": "Truelove-Witts",
   "category": "Hepatology & GI",
   "url": "https://askcalc.site/calc/truelove-witts/",
   "summary": "Truelove and Witts criteria classify ulcerative colitis flares. Acute severe UC = ≥6 bloody stools/day plus at least one sign of systemic toxicity: temperature >37.8 °C, pulse >90/min, hemoglobin <10.5 g/dL, or ESR >30 mm/h (CRP >30 mg/L in modified criteria); it warrants admission and IV steroids.",
   "formula": "Severe = ≥6 bloody stools/day AND ≥1 of: temperature >37.8 °C, pulse >90/min, Hb <10.5 g/dL, ESR >30 mm/h (modified: CRP >30 mg/L). Mild = ≤4 stools/day, small or no blood, no systemic signs. Moderate = in between.",
   "inputs": [
    {
     "id": "stools",
     "label": "Bowel movements per day",
     "kind": "num",
     "min": 0,
     "max": 50
    },
    {
     "id": "blood",
     "label": "Blood in stool",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None"
      },
      {
       "value": "small",
       "label": "Small amounts / intermittent"
      },
      {
       "value": "frequent",
       "label": "Frequent or large amounts"
      }
     ]
    },
    {
     "id": "temp",
     "label": "Temperature",
     "kind": "num",
     "unit": "°C",
     "units": [
      "°C",
      "°F"
     ],
     "min": 30,
     "max": 45
    },
    {
     "id": "hr",
     "label": "Heart rate",
     "kind": "num",
     "unit": "/min",
     "units": [
      "/min"
     ],
     "min": 20,
     "max": 250
    },
    {
     "id": "hgb",
     "label": "Hemoglobin",
     "kind": "num",
     "unit": "g/dL",
     "units": [
      "g/dL",
      "g/L"
     ],
     "min": 2,
     "max": 25
    },
    {
     "id": "esr",
     "label": "ESR",
     "kind": "num",
     "min": 0,
     "max": 200,
     "optional": true
    },
    {
     "id": "crp",
     "label": "CRP (mg/L)",
     "kind": "num",
     "min": 0,
     "max": 600,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Truelove SC, Witts LJ. Cortisone in ulcerative colitis: final report on a therapeutic trial. Br Med J 1955;2:1041–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/13260656/"
    },
    {
     "title": "Travis SP et al. Predicting outcome in severe ulcerative colitis. Gut 1996;38:905–10.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8984031/"
    }
   ]
  },
  {
   "id": "urine-anion-gap",
   "name": "Urine Anion Gap",
   "short": "Urine AG",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/urine-anion-gap/",
   "summary": "Urine anion gap = urine Na + urine K − urine Cl, a surrogate for urinary ammonium in normal-anion-gap metabolic acidosis. A negative gap suggests GI bicarbonate loss (diarrhoea); a positive gap suggests impaired renal acidification (distal RTA).",
   "formula": "UAG = U_Na⁺ + U_K⁺ − U_Cl⁻ (mmol/L)",
   "inputs": [
    {
     "id": "una",
     "label": "Urine sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 0,
     "max": 400
    },
    {
     "id": "uk",
     "label": "Urine potassium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "ucl",
     "label": "Urine chloride",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 0,
     "max": 400
    }
   ],
   "references": [
    {
     "title": "Batlle DC et al. The use of the urinary anion gap in the diagnosis of hyperchloremic metabolic acidosis. N Engl J Med 1988;318:594–9.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3344005/"
    }
   ]
  },
  {
   "id": "urine-osmolal-gap",
   "name": "Urine Osmolal Gap",
   "short": "Urine osmolal gap",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/urine-osmolal-gap/",
   "summary": "Urine osmolal gap = measured urine osmolality − [2 × (urine Na + K) + urine urea nitrogen/2.8 + urine glucose/18]; urine NH₄⁺ ≈ gap ÷ 2. In a normal-anion-gap metabolic acidosis a gap below ~150 mOsm/kg means inappropriately low ammonium excretion (renal tubular acidosis); much higher values indicate an appropriate renal response (e.g. diarrhoea).",
   "formula": "UOG = measured Uosm − [2 × (UNa + UK) + UUN (mg/dL)/2.8 + Uglucose (mg/dL)/18]. SI: 2(UNa + UK) + Uurea + Uglucose (mmol/L). Urine NH₄⁺ ≈ UOG ÷ 2.",
   "inputs": [
    {
     "id": "uosm",
     "label": "Measured urine osmolality",
     "kind": "num",
     "unit": "mOsm/kg",
     "units": [
      "mOsm/kg"
     ],
     "min": 30,
     "max": 1500
    },
    {
     "id": "una",
     "label": "Urine sodium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "uk",
     "label": "Urine potassium",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 0,
     "max": 300
    },
    {
     "id": "uun",
     "label": "Urine urea nitrogen",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 1,
     "max": 3000
    },
    {
     "id": "uglu",
     "label": "Urine glucose",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "mmol/L"
     ],
     "min": 0,
     "max": 5000,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Kim GH et al. Evaluation of urine acidification by urine anion gap and urine osmolal gap in chronic metabolic acidosis. Am J Kidney Dis 1996;27:42–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/8546137/"
    }
   ]
  },
  {
   "id": "upcr-proteinuria",
   "name": "Urine Protein:Creatinine Ratio (Estimated 24-h Proteinuria)",
   "short": "UPCR",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/upcr-proteinuria/",
   "summary": "A spot urine protein:creatinine ratio in mg/mg (g/g) approximates daily protein excretion in g/day. <0.15 g/g (15 mg/mmol) is normal-to-mild, 0.15–0.5 moderately increased, >0.5 severely increased, and >3.5 g/day is nephrotic range.",
   "formula": "UPCR (mg/mg) = urine protein (mg/dL) ÷ urine creatinine (mg/dL) ≈ g protein/day. 1 g/g = 1000 mg/g = 113 mg/mmol. SI: protein (g/L) × 1000 ÷ creatinine (mmol/L) = mg/mmol.",
   "inputs": [
    {
     "id": "uprot",
     "label": "Urine protein",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "g/L",
      "mg/L"
     ],
     "min": 0.5,
     "max": 5000
    },
    {
     "id": "ucreat",
     "label": "Urine creatinine",
     "kind": "num",
     "unit": "mg/dL",
     "units": [
      "mg/dL",
      "µmol/L",
      "mmol/L"
     ],
     "min": 1,
     "max": 1000
    }
   ],
   "references": [
    {
     "title": "Ginsberg JM et al. Use of single voided urine samples to estimate quantitative proteinuria. N Engl J Med 1983;309:1543–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/6656849/"
    },
    {
     "title": "KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD. Kidney Int 2024;105(4S):S117–S314.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/38490803/"
    }
   ]
  },
  {
   "id": "dose-weight-based",
   "name": "Weight-Based Dose Calculator (mg/kg with maximum dose)",
   "short": "mg/kg dose",
   "category": "Pharmacology & Dosing",
   "url": "https://askcalc.site/calc/dose-weight-based/",
   "summary": "Calculates a weight-based dose as mg/kg × weight (kg), capped at an optional maximum single dose, and converts it to a volume if a concentration (mg/mL) is given. Always check the dose against the product label or a pediatric formulary.",
   "formula": "Dose (mg) = dose (mg/kg) × weight (kg); if a maximum is given, dose = min(calculated, maximum). Volume (mL) = dose ÷ concentration (mg/mL).",
   "inputs": [
    {
     "id": "weight",
     "label": "Weight",
     "kind": "num",
     "unit": "kg",
     "units": [
      "kg",
      "lb"
     ],
     "min": 0.3,
     "max": 400
    },
    {
     "id": "mgkg",
     "label": "Dose per kg (mg/kg)",
     "kind": "num",
     "min": 0,
     "max": 1000
    },
    {
     "id": "max",
     "label": "Maximum dose (mg), optional",
     "kind": "num",
     "min": 0,
     "max": 100000,
     "optional": true
    },
    {
     "id": "conc",
     "label": "Concentration (mg/mL), optional",
     "kind": "num",
     "min": 0.0001,
     "max": 10000,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Pan SD et al. Weight-based dosing in medication use: what should we know? Patient Prefer Adherence 2016;10:549–60.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/27110105/"
    }
   ]
  },
  {
   "id": "wells-dvt",
   "name": "Wells Score for Deep Vein Thrombosis",
   "short": "Wells DVT",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/wells-dvt/",
   "summary": "The modified Wells DVT score (−2 to 9) estimates pretest probability of lower-limb deep vein thrombosis: ≥2 \"DVT likely\" (ultrasound), <2 \"DVT unlikely\" (D-dimer first; if negative, DVT excluded).",
   "formula": "One point each: active cancer · paralysis/paresis/cast · bedridden ≥ 3 d or surgery < 12 wk · deep-vein tenderness · entire leg swollen · calf swelling ≥ 3 cm · pitting edema (symptomatic leg) · collateral superficial veins · previous DVT. Minus 2 if an alternative diagnosis is at least as likely.",
   "inputs": [
    {
     "id": "cancer",
     "label": "Active cancer (treatment within 6 months or palliative)",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "paralysis",
     "label": "Paralysis, paresis or recent plaster cast of the leg",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "bedridden",
     "label": "Bedridden ≥ 3 days or major surgery within 12 weeks",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "tender",
     "label": "Localized tenderness along the deep venous system",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "leg_swollen",
     "label": "Entire leg swollen",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "calf_3cm",
     "label": "Calf swelling ≥ 3 cm vs other leg",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "pitting",
     "label": "Pitting edema confined to the symptomatic leg",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "collaterals",
     "label": "Collateral (non-varicose) superficial veins",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "prior_vte",
     "label": "Previously documented DVT",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "alt_dx",
     "label": "Alternative diagnosis at least as likely as DVT",
     "kind": "yn",
     "points": -2
    }
   ],
   "references": [
    {
     "title": "Wells PS et al. Evaluation of D-dimer in the diagnosis of suspected deep-vein thrombosis. N Engl J Med 2003;349:1227–35.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/14507948/"
    },
    {
     "title": "Wells PS et al. Value of assessment of pretest probability of deep-vein thrombosis in clinical management. Lancet 1997;350:1795–8.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/9428249/"
    }
   ]
  },
  {
   "id": "wells-pe",
   "name": "Wells Score for Pulmonary Embolism",
   "short": "Wells PE",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/wells-pe/",
   "summary": "The Wells PE score (0–12.5) estimates pretest probability of pulmonary embolism. Two-tier: ≤4 \"PE unlikely\" (D-dimer first), >4 \"PE likely\" (CT pulmonary angiography). Three-tier: <2 low, 2–6 moderate, >6 high.",
   "formula": "Clinical DVT signs 3 · PE most likely diagnosis 3 · HR > 100: 1.5 · immobilization ≥ 3 d or surgery < 4 wk 1.5 · previous DVT/PE 1.5 · hemoptysis 1 · malignancy 1",
   "inputs": [
    {
     "id": "dvt_signs",
     "label": "Clinical signs and symptoms of DVT",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "pe_likely",
     "label": "PE is the most likely diagnosis (or equally likely)",
     "kind": "yn",
     "points": 3
    },
    {
     "id": "tachy",
     "label": "Heart rate > 100",
     "kind": "yn",
     "points": 1.5
    },
    {
     "id": "immob",
     "label": "Immobilization ≥ 3 days or surgery in the previous 4 weeks",
     "kind": "yn",
     "points": 1.5
    },
    {
     "id": "prior_vte",
     "label": "Previous DVT or PE",
     "kind": "yn",
     "points": 1.5
    },
    {
     "id": "hemoptysis",
     "label": "Hemoptysis",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "cancer",
     "label": "Malignancy (on treatment, treated in last 6 months, or palliative)",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Wells PS et al. Derivation of a simple clinical model to categorize patients probability of pulmonary embolism. Thromb Haemost 2000;83:416–20.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/10744147/"
    },
    {
     "title": "Wells PS et al. Excluding pulmonary embolism at the bedside without diagnostic imaging. Ann Intern Med 2001;135:98–107.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/11453709/"
    }
   ]
  },
  {
   "id": "westley-croup",
   "name": "Westley Croup Score",
   "short": "Westley",
   "category": "Pediatrics & Obstetrics",
   "url": "https://askcalc.site/calc/westley-croup/",
   "summary": "The Westley croup score (0–17) grades croup severity from level of consciousness, cyanosis, stridor, air entry and retractions: ≤2 mild, 3–7 moderate, 8–11 severe, ≥12 impending respiratory failure.",
   "formula": "LOC: normal 0, disoriented 5 · Cyanosis: none 0, with agitation 4, at rest 5 · Stridor: none 0, with agitation 1, at rest 2 · Air entry: normal 0, decreased 1, markedly decreased 2 · Retractions: none 0, mild 1, moderate 2, severe 3",
   "inputs": [
    {
     "id": "loc",
     "label": "Level of consciousness",
     "kind": "sel",
     "options": [
      {
       "value": "normal",
       "label": "Normal (including asleep)",
       "points": 0
      },
      {
       "value": "disoriented",
       "label": "Disoriented",
       "points": 5
      }
     ]
    },
    {
     "id": "cyanosis",
     "label": "Cyanosis",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "agitation",
       "label": "With agitation",
       "points": 4
      },
      {
       "value": "rest",
       "label": "At rest",
       "points": 5
      }
     ]
    },
    {
     "id": "stridor",
     "label": "Stridor",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "agitation",
       "label": "With agitation",
       "points": 1
      },
      {
       "value": "rest",
       "label": "At rest",
       "points": 2
      }
     ]
    },
    {
     "id": "airEntry",
     "label": "Air entry",
     "kind": "sel",
     "options": [
      {
       "value": "normal",
       "label": "Normal",
       "points": 0
      },
      {
       "value": "decreased",
       "label": "Decreased",
       "points": 1
      },
      {
       "value": "marked",
       "label": "Markedly decreased",
       "points": 2
      }
     ]
    },
    {
     "id": "retractions",
     "label": "Retractions",
     "kind": "sel",
     "options": [
      {
       "value": "none",
       "label": "None",
       "points": 0
      },
      {
       "value": "mild",
       "label": "Mild",
       "points": 1
      },
      {
       "value": "moderate",
       "label": "Moderate",
       "points": 2
      },
      {
       "value": "severe",
       "label": "Severe",
       "points": 3
      }
     ]
    }
   ],
   "references": [
    {
     "title": "Westley CR, Cotton EK, Brooks JG. Nebulized racemic epinephrine by IPPB for the treatment of croup: a double-blind study. Am J Dis Child 1978;132:484–7.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/347921/"
    }
   ]
  },
  {
   "id": "wfns",
   "name": "WFNS Grade for Subarachnoid Hemorrhage",
   "short": "WFNS",
   "category": "Neurology",
   "url": "https://askcalc.site/calc/wfns/",
   "summary": "The WFNS scale grades aneurysmal subarachnoid haemorrhage I–V from the GCS and presence of a major focal motor deficit: I = GCS 15; II = GCS 13–14 without deficit; III = GCS 13–14 with deficit; IV = GCS 7–12; V = GCS 3–6. Grades IV–V are \"poor grade\".",
   "formula": "Grade I: GCS 15 · II: GCS 13–14, no major motor deficit · III: GCS 13–14 with deficit · IV: GCS 7–12 · V: GCS 3–6",
   "inputs": [
    {
     "id": "gcs",
     "label": "Glasgow Coma Scale",
     "kind": "num",
     "min": 3,
     "max": 15
    },
    {
     "id": "motor",
     "label": "Major focal motor deficit (hemiparesis/aphasia)",
     "kind": "yn",
     "points": 1
    }
   ],
   "references": [
    {
     "title": "Report of World Federation of Neurological Surgeons Committee on a Universal Subarachnoid Hemorrhage Grading Scale. J Neurosurg 1988;68:985–6.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/3131498/"
    }
   ]
  },
  {
   "id": "winters-formula",
   "name": "Winters' Formula (Expected pCO2 in Metabolic Acidosis)",
   "short": "Winters'",
   "category": "Nephrology & Electrolytes",
   "url": "https://askcalc.site/calc/winters-formula/",
   "summary": "Winters' formula predicts the pCO₂ in a compensated metabolic acidosis: expected pCO₂ = 1.5 × HCO₃ + 8 ± 2 mmHg. A measured pCO₂ above the range means a concurrent respiratory acidosis; below it, a concurrent respiratory alkalosis.",
   "formula": "Expected pCO₂ (mmHg) = 1.5 × HCO₃⁻ + 8 ± 2. (kPa = mmHg ÷ 7.5)",
   "inputs": [
    {
     "id": "hco3",
     "label": "Serum bicarbonate (HCO₃⁻)",
     "kind": "num",
     "unit": "mmol/L",
     "units": [
      "mmol/L",
      "mEq/L"
     ],
     "min": 1,
     "max": 30
    },
    {
     "id": "pco2",
     "label": "Measured pCO₂ (optional)",
     "kind": "num",
     "unit": "mmHg",
     "units": [
      "mmHg",
      "kPa"
     ],
     "min": 5,
     "max": 150,
     "optional": true
    }
   ],
   "references": [
    {
     "title": "Albert MS, Dell RB, Winters RW. Quantitative displacement of acid-base equilibrium in metabolic acidosis. Ann Intern Med 1967;66:312–22.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/6016545/"
    },
    {
     "title": "Berend K, de Vries APJ, Gans ROB. Physiological approach to assessment of acid–base disturbances. N Engl J Med 2014;371:1434–45.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/25295502/"
    }
   ]
  },
  {
   "id": "years-algorithm",
   "name": "YEARS Algorithm for Pulmonary Embolism",
   "short": "YEARS",
   "category": "Cardiology",
   "url": "https://askcalc.site/calc/years-algorithm/",
   "summary": "YEARS rules out PE without imaging when there are no YEARS items (clinical signs of DVT, hemoptysis, PE most likely diagnosis) and D-dimer < 1000 ng/mL, or ≥1 item and D-dimer < 500 ng/mL; everyone else gets CTPA. It cut CTPA use by 14% versus Wells with a 0.61% 3-month VTE rate.",
   "formula": "YEARS items: clinical signs of DVT, hemoptysis, PE most likely diagnosis. Threshold = 1000 ng/mL FEU if 0 items, 500 ng/mL if ≥1 item. D-dimer below threshold → PE excluded.",
   "inputs": [
    {
     "id": "dvt_signs",
     "label": "Clinical signs of deep vein thrombosis",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "hemoptysis",
     "label": "Hemoptysis",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "pe_likely",
     "label": "PE is the most likely diagnosis",
     "kind": "yn",
     "points": 1
    },
    {
     "id": "ddimer",
     "label": "D-dimer (FEU)",
     "kind": "num",
     "unit": "ng/mL",
     "units": [
      "ng/mL",
      "µg/L",
      "mg/L"
     ],
     "min": 10,
     "max": 100000
    }
   ],
   "references": [
    {
     "title": "van der Hulle T et al. Simplified diagnostic management of suspected pulmonary embolism (the YEARS study). Lancet 2017;390:289–97.",
     "url": "https://pubmed.ncbi.nlm.nih.gov/28549662/"
    }
   ]
  }
 ]
}