CRB-65 Pneumonia Severity Calculator
CRB-65 estimates 30-day mortality in community-acquired pneumonia from four bedside factors — Confusion, Respiratory rate ≥30, low Blood pressure and age ≥65 — without needing blood tests, to help decide on hospital referral.
Quick answer
CRB-65 scores four bedside features of community-acquired pneumonia — new Confusion, Respiratory rate 30 or more, low Blood pressure, and age 65 or over — from 0 to 4. It drops the urea blood test from CURB-65 so it can be used in the community: 0 is low risk, 1–2 intermediate, and 3–4 high risk.
CRB-65 criteria
Low risk (30-day mortality <1%) — generally suitable for home/outpatient management.
A CRB-65 of 0. The score drops the urea blood test from CURB-65 so it can be used without bloods (for example in primary care), and supports the admission decision alongside oxygen saturation and clinical judgement.
Validated formula
1 point for each present feature (maximum 4): Confusion (new) = 1; Respiratory rate ≥30/min = 1; low Blood pressure (systolic <90 mmHg or diastolic ≤60 mmHg) = 1; age ≥65 years = 1. Total = 0–4. Urea is omitted (vs CURB-65) so it can be applied without bloods in the community.
Interpretation
- 0— Low risk (30-day mortality <1%) — generally suitable for home/outpatient management.
- 1–2— Intermediate risk (~1–10% mortality) — consider hospital assessment/referral.
- 3–4— High risk (~10% or higher mortality; up to ~17–50% at score 3) — urgent hospital admission, consider critical care.
How to use the CRB-65 calculator
- 1Tick the four criteria. Tick new confusion, respiratory rate 30 or more per minute, low blood pressure (systolic under 90 or diastolic 60 or less), and age 65 or over.
- 2Read the score. The tool totals the points from 0 to 4.
- 3Use it to support referral. 0 often suits home care, 1–2 suggests considering hospital assessment, and 3–4 suggests urgent admission — alongside oxygen levels and clinical judgement.
Medical disclaimer: This is general health information, not medical advice. It does not diagnose or treat any condition, and the results are estimates based on public reference formulas. Always consult a qualified doctor about your individual health. If you think you may have a medical emergency, contact your local emergency services immediately.
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Book a consultationFrequently asked questions
What is the difference between CRB-65 and CURB-65?⌄
CRB-65 omits the urea (blood) criterion so it can be applied without bloods, for example in primary care or at home. CURB-65 adds urea and is used where blood tests are available.
What CRB-65 score needs hospital admission?⌄
Broadly, 0 can often be managed at home, 1–2 warrants considering hospital assessment, and 3–4 warrants urgent admission with consideration of critical care. A clinician decides using the whole picture.
Does CRB-65 diagnose pneumonia?⌄
No. It assumes pneumonia is already diagnosed and estimates its severity and 30-day mortality risk to guide where care should happen.
Sources & validation
This calculator reproduces the published CRB-65 score, validated for 30-day mortality and admission triage in community-acquired pneumonia (no bloods needed).
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