What does each letter in CURB-65 stand for?

C = Confusion (new acute disorientation), U = Urea above 7 mmol/L, R = Respiratory rate 30 or more breaths per minute, B = Blood pressure with systolic below 90 or diastolic at or below 60 mmHg, 65 = Age 65 or older. Each criterion present adds 1 point, giving a maximum score of 5.

What is the BUN threshold in mg/dL?

The CURB-65 urea cutoff is 7 mmol/L. To convert from BUN (blood urea nitrogen) in mg/dL, divide by 2.8. A BUN of approximately 19.6 mg/dL equals 7 mmol/L — any value above that scores 1 point.

Which score indicates ICU admission?

Scores of 4 or 5 indicate very high risk (estimated 30-day mortality 40–57%) and should prompt consideration of ICU or high-dependency unit admission. A score of 3 mandates hospital admission with assessment for possible escalation if the patient deteriorates.

Can CURB-65 replace clinical judgment?

No. CURB-65 is a validated decision-support tool, not a standalone protocol. Factors such as oxygenation, comorbidities, social support, and response to initial therapy must also guide management. All clinical decisions must be made by qualified healthcare professionals.

How does CURB-65 compare to PSI (PORT score)?

PSI uses 20 variables and stratifies patients into five risk classes. CURB-65 uses five bedside variables and three risk tiers. Both have similar predictive accuracy in most studies. CURB-65 is faster to apply at the bedside; PSI is more granular for low-risk identification.

Is CURB-65 valid for hospital-acquired or healthcare-associated pneumonia?

No. CURB-65 was validated for community-acquired pneumonia in adults. It is not validated for hospital-acquired pneumonia, ventilator-associated pneumonia, or pneumonia in immunocompromised patients, where different scoring systems and broader empirical coverage are needed.

CURB-65 Pneumonia Severity Score

Name: CURB-65 Pneumonia Severity Score
Availability: InStock
Author: Nham Vu

Score five bedside criteria to stratify CAP severity and get a treatment setting recommendation — outpatient, inpatient, or ICU.

Educational use only. This tool is not a substitute for clinical judgment. All pneumonia management decisions must be made by qualified clinicians based on full patient assessment including oxygenation, comorbidities, and social circumstances.

Five Bedside Criteria

Each criterion present adds 1 point. Maximum score: 5.

Confusion

New acute confusion or disorientation — not pre-existing dementia or prior cognitive impairment.

No confusion Confused

Blood Urea / BUN

Scores 1 point if urea > 7 mmol/L (BUN > 19.6 mg/dL). Enter value or select manually.

Urea ≤ 7 mmol/L Urea > 7 mmol/L

Entering a numeric value overrides the manual selection.

Respiratory Rate

Scores 1 point if ≥ 30 breaths per minute.

breaths/min

Blood Pressure

Scores 1 point if systolic < 90 mmHg or diastolic ≤ 60 mmHg.

/ mmHg

Age ≥ 65 years

Scores 1 point if the patient is 65 years or older.

Age < 65 Age ≥ 65

Enter the five criteria
and click Calculate.

Score Interpretation & Treatment Setting Reference

Score	Risk	30-Day Mortality	Treatment Setting
0 – 1	Low	~0.6–2.7%	Outpatient oral antibiotics with close follow-up
2	Moderate	~9.2%	Short inpatient stay or closely supervised outpatient care
3	High	~14.5%	Hospital admission required
4 – 5	Very High	~40–57%	Hospital + consider ICU / high-dependency unit

Summary

Score five bedside criteria to stratify CAP severity and get a treatment setting recommendation — outpatient, inpatient, or ICU.

How it works

Select whether the patient has new acute confusion — not baseline dementia.
Enter BUN in mmol/L or mg/dL; the calculator converts automatically and applies the 7 mmol/L threshold.
Enter the respiratory rate; 30 or more breaths per minute scores 1 point.
Enter systolic and/or diastolic blood pressure; hypotension (systolic < 90 or diastolic ≤ 60 mmHg) scores 1 point.
Select whether the patient is aged 65 or older.
Click Calculate to see the CURB-65 score, 30-day mortality estimate, and a treatment setting recommendation.

Use cases

Decide between outpatient and inpatient treatment for adults with community-acquired pneumonia.
Identify patients who may need ICU-level care based on a score of 4 or 5.
Triage pneumonia patients in the emergency department using five rapid bedside assessments.
Convert BUN values from mg/dL to mmol/L when applying the CURB-65 urea threshold.
Communicate standardized severity to admitting teams during handover.
Use as a teaching aid for medical students learning pneumonia management guidelines.
Complement clinical judgment when determining the safest care setting for a patient.
Track serial CURB-65 scores to monitor clinical progression or improvement.

Frequently Asked Questions

Last updated: 2026-07-23 · Reviewed by Nham Vu