curb 65 calculator

What is CURB-65?

CURB-65 is a simple clinical scoring tool used to estimate illness severity in adults with community-acquired pneumonia. The score helps support triage decisions such as outpatient treatment, brief inpatient observation, or hospital admission. It is popular because it is fast, practical, and based on variables that are usually available early in assessment.

How the score is built

CURB-65 assigns one point for each of five findings. The total score ranges from 0 to 5.

C — Confusion

New mental status change (for example, disorientation or altered consciousness) suggests physiologic stress and poorer prognosis.

U — Urea

Elevated urea (or BUN) may indicate dehydration, renal involvement, or severe systemic illness. In this calculator, the threshold is >19 mg/dL BUN or >7 mmol/L urea.

R — Respiratory rate

A respiratory rate of 30 breaths/min or higher is a high-risk sign of respiratory compromise and predicts worse outcomes.

B — Blood pressure

Hypotension is scored if systolic pressure is below 90 mmHg or diastolic pressure is 60 mmHg or lower.

65 — Age 65 or older

Age is a major risk factor in pneumonia severity models. Patients aged 65+ receive one additional point.

Interpreting CURB-65 results

• 0–1 points: lower risk; outpatient treatment may be appropriate in selected patients.
• 2 points: intermediate risk; consider hospital-supervised treatment or short inpatient stay.
• 3–5 points: high risk; urgent hospital management is generally recommended, with possible ICU evaluation for higher scores.

In many references, mortality risk rises substantially with each additional point. This calculator reports a commonly cited approximate mortality range to support context, not to predict an individual outcome.

CURB-65 vs CRB-65

If lab data are unavailable (especially urea/BUN), clinicians sometimes use CRB-65, which removes the urea component and can be used in office or prehospital settings. CURB-65 is generally preferred when laboratory values are available because it offers stronger risk discrimination.

Important limitations

• CURB-65 was designed for adults with suspected community-acquired pneumonia, not all respiratory infections.
• It does not replace full clinical evaluation, oxygenation assessment, comorbidity review, or social/functional considerations.
• It may under-represent severity in younger patients with significant hypoxemia or multilobar disease.
• Use with caution in immunocompromised patients, nursing-home residents, and complex chronic disease populations.

Practical use tips

• Use CURB-65 alongside physical exam, pulse oximetry, chest imaging, and clinical trajectory.
• Recalculate when the patient status changes; early deterioration can occur.
• Document rationale when treatment setting differs from score-based suggestions.

Bottom line

This curb 65 calculator gives you a fast, transparent way to compute CURB-65 and support evidence-based triage discussions. It is best used as one part of a complete pneumonia severity assessment, not as a standalone diagnostic or disposition rule.