Nephrology & Electrolytes Calculators
27 calculators.
Albumin-Corrected Delta GapAlbumin-corrected delta gap = albumin-corrected anion gap − 12, where corrected AG = Na…Albumin-Corrected Delta RatioAlbumin-corrected delta ratio = (albumin-corrected AG − 12) ÷ (24 − HCO₃), with…Bedside Schwartz eGFR (Pediatric)The 2009 bedside Schwartz equation estimates GFR in children as 0.413 × height (cm) ÷…Bicarbonate DeficitBicarbonate deficit = 0.5 × weight (kg) × (target − measured HCO₃) mmol. Give about half…BUN:Creatinine Ratio (Urea:Creatinine)BUN:creatinine ratio (both mg/dL) is normally 10–20. A ratio >20 suggests prerenal…Calculated Serum OsmolalityCalculated serum osmolality = 2 × Na + glucose/18 + BUN/2.8 (mg/dL), or in SI units 2 ×…Corrected Calcium for AlbuminCorrected calcium = measured calcium + 0.8 × (4.0 − albumin g/dL), or in SI units Ca +…Corrected Sodium in HyperglycemiaIn hyperglycaemia, serum sodium falls as water shifts out of cells. Corrected Na = Na +…Creatinine Clearance (Cockcroft-Gault)Cockcroft-Gault estimates creatinine clearance as (140 − age) × weight ÷ (72 × serum…Delta Gap and Delta RatioThe delta ratio (ΔAG ÷ ΔHCO₃, with AG normal 12 and HCO₃ normal 24) detects mixed…eGFR (CKD-EPI 2021 Creatinine–Cystatin C)The race-free 2021 CKD-EPI creatinine–cystatin C equation combines both markers and is…eGFR (CKD-EPI 2021, race-free)Estimates glomerular filtration rate from serum creatinine, age and sex using the…eGFR (MDRD Study equation)The 4-variable IDMS-traceable MDRD equation, 175 × Scr^−1.154 × age^−0.203 (× 0.742…Expected HCO₃ in Respiratory Acidosis / AlkalosisExpected HCO₃ for a primary respiratory disorder per 10 mmHg change in pCO₂ from 40:…Expected pCO₂ in Metabolic AlkalosisIn metabolic alkalosis pCO₂ rises about 0.7 mmHg per 1 mmol/L rise in HCO₃: expected…Fractional Excretion of Sodium (FENa)FENa = (urine Na × plasma creatinine) ÷ (plasma Na × urine creatinine) × 100. In…Fractional Excretion of Urea (FEUrea)FEUrea = (urine urea × plasma creatinine) ÷ (plasma urea × urine creatinine) × 100.…Free Water Deficit in HypernatremiaFree water deficit = total body water × (Na/140 − 1), with TBW = 0.6 × weight (men), 0.5…Kidney Failure Risk Equation (KFRE, 4-variable)The 4-variable KFRE (age, sex, eGFR, urine ACR) predicts 2- and 5-year risk of kidney…Serum Anion Gap (with Albumin Correction)Anion gap = Na − (Cl + HCO₃). A typical normal value is about 8–12 mmol/L…Serum Osmolal GapOsmolal gap = measured osmolality − (2 × Na + glucose/18 + BUN/2.8 [+ ethanol/3.7]). A…Sodium Change per Litre of Infusate (Adrogué–Madias)The Adrogué–Madias formula estimates the change in serum sodium after 1 L of a fluid:…Transtubular Potassium Gradient (TTKG)TTKG = (urine K ÷ plasma K) × (plasma osm ÷ urine osm), an index of distal potassium…Urine Anion GapUrine anion gap = urine Na + urine K − urine Cl, a surrogate for urinary ammonium in…Urine Osmolal GapUrine osmolal gap = measured urine osmolality − [2 × (urine Na + K) + urine urea…Urine Protein:Creatinine Ratio (Estimated 24-h Proteinuria)A spot urine protein:creatinine ratio in mg/mg (g/g) approximates daily protein…Winters' Formula (Expected pCO₂ in Metabolic Acidosis)Winters' formula predicts the pCO₂ in a compensated metabolic acidosis: expected pCO₂ =…