emergency & critical carescoring tool

CURB-65

CURB-65 stratifies community-acquired pneumonia severity using five bedside criteria to guide place-of-care decisions. Each criterion scores 1 point: Confusion, Urea >7 mmol/L, Respiratory rate ≥30, Blood pressure (systolic <90 or diastolic ≤60), and age ≥65.

inputs

Positive if >7 mmol/L (>19.6 mg/dL)
Positive if ≥30 breaths/min
breaths/min
Positive if <90 mmHg
mmHg
Positive if ≤60 mmHg
mmHg
Positive if ≥65 years
years

✓ when to use

Use in adults presenting with suspected or confirmed community-acquired pneumonia to guide disposition decisions (outpatient vs inpatient vs ICU). Applicable in ED, acute medicine, and primary care settings. CRB-65 (omitting urea) can be used in community settings where blood tests are not immediately available.

✗ when not to use

Not validated for hospital-acquired or ventilator-associated pneumonia. Does not account for comorbidities, immunosuppression, empyema, or multilobar disease — clinical judgement must supplement the score. May underestimate severity in young patients with severe disease (e.g., a 30-year-old with septic shock from pneumonia would score only 1–2). Not validated in children.

clinical pearls

  • CRB-65 (dropping urea) can be calculated without blood tests and is suitable for GP or community triage. It uses the same thresholds: 0 = low risk, 1–2 = intermediate, 3–4 = high.
  • CURB-65 predicts mortality, not necessarily need for admission. A score of 0 still requires clinical assessment — a patient with empyema, significant hypoxia, or social vulnerability may need admission regardless of score.
  • CURB-65 systematically underestimates risk in younger adults because age ≥65 contributes a point. A 30-year-old with confusion, high urea, tachypnoea, and hypotension only scores 4/5 — but this is clearly severe disease. Always integrate clinical impression.
  • Consider the pneumonia severity index (PSI/PORT) as an alternative in settings where more granular risk stratification is needed, particularly for identifying low-risk patients suitable for outpatient management.
  • In the UK, NICE suggests CURB-65 0–1 for home treatment, 2 for consideration of hospital-based assessment (including virtual ward/SDEC), and ≥3 for inpatient care with ICU review.

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