CURB-65 Calculator (Pneumonia Severity)

CURB-65 = Confusion + Urea>7 + RR≥30 + BP<90/60 + Age≥65. Lim 2003 Thorax. Predicts 30-day pneumonia mortality.

Result

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How to use this calculator

Assess each criterion at presentation.
Read score + 30-day mortality estimate.
Use alongside oxygenation + clinical judgment for admission decisions.

About this calculator

CURB-65 stratifies community-acquired pneumonia (CAP) by 30-day mortality and informs admission decisions. Source: Lim WS et al., "Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study." Thorax 2003;58(5):377-82. Validated in 1,068 patients from 3 countries. Mortality bands: 0 (0.7%), 1 (2.1%), 2 (9.2%), 3 (14.5%), 4 (40%), 5 (57%). BTS/IDSA guidelines: score 0-1 outpatient, 2 ward (short stay), 3-5 inpatient (ICU consider ≥3-4). Variant CRB-65 omits urea (no labs needed; useful in primary care). **Not medical advice — clinical context (oxygenation, comorbidities) drives admission decisions.**

Frequently asked

Source of the score?+

Lim WS et al., Thorax 2003;58:377-82. International (UK/NL/NZ) prospective validation in 1,068 CAP patients.

CURB-65 vs. PSI/PORT?+

PSI (Fine 1997) is more accurate but uses 20 variables. CURB-65 uses 5; faster bedside, similar discrimination at the high-risk end. IDSA endorses both.

CRB-65?+

Drops Urea — no labs required. Score 1 ≤ admit consider; ≥2 admit. Useful in primary care or pre-hospital.

When does CURB-65 fail?+

Underestimates severity in immunocompromised, severe hypoxemia (PaO₂/FiO₂ < 250), young patients with sepsis. Always factor SpO₂ + vitals.

Mortality numbers?+

0: 0.7%; 1: 2.1%; 2: 9.2%; 3: 14.5%; 4: 40%; 5: 57% (Lim 2003 Table 4).

Is this medical advice?+

No. Educational. Pneumonia disposition requires clinical context.

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