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CURB-65 Score for Pneumonia Severity

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).

Age (years)
New confusion (disorientation to person, place or time) (yes/no, +1)
BUN (or urea in mmol/L) (mg/dL or mmol/L)
Respiratory rate (/min)
Systolic blood pressure (mmHg or kPa)
Diastolic blood pressure (mmHg or kPa)

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Interpretation

Result	Meaning
0–1	Low risk (group 1, ~1.5% mortality): outpatient
2	Intermediate (group 2, ~9.2%): short stay or supervised outpatient
3–5	Severe (group 3, ~22%): admit; 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

Clinical pearls

CURB-65 underestimates severity in young patients with hypoxemia; SpO₂ <92% warrants admission regardless of score.
It does not capture comorbidity, social factors or ability to take oral therapy; clinical judgment overrides a low score.
Where urea/BUN is unavailable (office setting), use CRB-65.

Examples

curb 65 for 72 yo confused, bun 28, rr 32, bp 88/50 curb-65 45M urea 6 mmol/L rr 22 bp 130/80 not confused pneumonia severity 80 year old woman, BUN 30, RR 24, BP 110/70

FAQ

What CURB-65 score requires hospital admission?

A score of 2 suggests short admission or supervised outpatient care; 3 or more indicates severe pneumonia needing hospitalization, with ICU assessment at 4–5.

What is the urea cut-off in CURB-65?

Urea >7 mmol/L, which corresponds to a BUN above about 19–20 mg/dL.

Evidence

Lim WS et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax 2003;58:377–82.

Pulmonary & Critical Care · Reviewed 2026-10-14 · Methodology