Infectious disease
CURB-65
CURB-65 grades the severity of community-acquired pneumonia and indicates where the patient should be treated. Five criteria, one point each, and the score maps to 30-day mortality.
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This calculator is provided for reference and education. It does not replace clinical assessment, examination, current guidelines, local protocol, or professional judgment. Verify every result before acting on it. Nirogix accepts no liability for clinical decisions made using this tool.
The formula
- C — new confusion: 1
- U — urea above 7 mmol/L (roughly BUN above 19 mg/dL): 1
- R — respiratory rate ≥ 30: 1
- B — systolic < 90 or diastolic ≤ 60 mmHg: 1
- 65 — age ≥ 65: 1
Worked example
An 80-year-old with a respiratory rate of 32 and urea of 9 → 1 + 1 + 1 = 3, severe
When to use it
- Deciding site of care for community-acquired pneumonia
And when not to
- It was derived for community-acquired pneumonia. It does not apply to hospital-acquired or aspiration pneumonia.
- It under-weights hypoxia and comorbidity. A young hypoxic patient can score 0 and still need admission.
- CRB-65 drops the urea for use where no blood test is available.
References
- Defining community acquired pneumonia severity on presentation to hospital — Lim WS et al., Thorax, 2003
Last reviewed 07/09/2026.
These calculators are free and always will be. We also build Nirogix, a hospital management system for Indian clinics and hospitals. The same calculations are planned inside the consultation record, pre-filled from the chart.