CURB-65 score in community-acquired pneumonia
CURB-65 describes the severity of community-acquired pneumonia at hospital presentation using five criteria, including urea. The calculator shows the score and the 30-day mortality observed in the original study.
⚠︎ Learning tool for medical education – not for use in patients or for treatment decisions.
Classification (original publication)
| Score | Classification (original publication) |
|---|---|
| 0 | 0 points – 30-day mortality 0.7% in the derivation cohort (Lim 2003) |
| 1 | 1 point – 30-day mortality 3.2% in the derivation cohort (Lim 2003) |
| 2 | 2 points – 30-day mortality 3% in the derivation cohort (Lim 2003) |
| 3 | 3 points – 30-day mortality 17% in the derivation cohort (Lim 2003) |
| 4 | 4 points – 30-day mortality 41.5% in the derivation cohort (Lim 2003) |
| 5 | 5 points – 30-day mortality 57% in the derivation cohort (Lim 2003) |
Original study
Lim et al. derived the score in 2003 from three prospective pneumonia studies from the UK, New Zealand and the Netherlands (1,068 patients, 30-day mortality 9%). In the derivation cohort, 30-day mortality was 0.7% with 0 points, 3.2% with 1 point, 3% with 2 points, 17% with 3 points, 41.5% with 4 points and 57% with 5 points. The validation cohort confirmed a similar pattern.
CURB-65 and CRB-65
The CRB-65 omits urea and needs no laboratory values (0–4 points). CURB-65 requires a urea measurement.
Converting urea
The original study uses urea > 7 mmol/l. Converted, this is about 42 mg/dl urea (× 6.006) or 19.6 mg/dl blood urea nitrogen (BUN, × 2.8).
FAQ
What does CURB-65 stand for?▾
C for confusion, U for urea > 7 mmol/l, R for respiratory rate ≥ 30/min, B for blood pressure (systolic < 90 or diastolic ≤ 60 mmHg) and 65 for age 65 or older.
Which mortality is associated with which score?▾
In the derivation cohort of Lim et al. (2003): 0 points 0.7%, 1 point 3.2%, 2 points 3%, 3 points 17%, 4 points 41.5%, 5 points 57% (30-day mortality).
References
- Lim WS et al. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax 2003;58:377–82. · PubMed
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Open in browser Download on the App StoreIntended purpose: learning tool for medical education only. Not intended for use in patients or for diagnostic or treatment decisions; not a medical device. Calculations follow the cited original publications; no guarantee of completeness or correctness. Last updated: 10/2026 · Dr. Pascal Bafteh