CURB-65 Pneumonia Severity Score
Calculates the CURB-65 score to assess the severity of community-acquired pneumonia (CAP) and guide treatment decisions regarding hospitalization vs outpatient management.
Patient Assessment
New disorientation in person, place, or time
BUN >19 mg/dL (or Urea >7 mmol/L) scores 1 point
Respiratory rate ≥30 breaths/min scores 1 point
SBP <90 mmHg scores 1 point
DBP ≤60 mmHg scores 1 point
Age ≥65 years scores 1 point
CURB-65 Criteria
CURB-65 Score
Enter values to calculate
About This Calculator
The CURB-65 score is a clinical prediction rule validated for estimating mortality risk in community-acquired pneumonia (CAP). It was developed from the British Thoracic Society's CURB criteria and validated in over 1,000 patients from prospective studies in the UK, New Zealand, and the Netherlands.
The acronym CURB-65 represents the five risk factors assessed: Confusion, Urea, Respiratory rate, Blood pressure, and age 65 or older. Each criterion scores one point, with a maximum score of 5.
The score helps clinicians determine appropriate treatment settings: • Low scores (0-1) typically indicate outpatient treatment is safe • Intermediate scores (2) suggest short hospital admission or hospital-supervised outpatient treatment • High scores (3-5) indicate hospitalization, with ICU consideration for scores of 4-5
CURB-65 is recommended by the British Thoracic Society and is widely used due to its simplicity and ease of calculation at the bedside.
Formula
CURB-65 Score = C + U + R + B + 65 (each criterion = 1 point, max = 5)Each criterion scores 1 point if present: • **C**onfusion: New mental confusion (AMTS ≤8 or disorientation to person, place, or time) • **U**rea: Blood urea nitrogen >19 mg/dL (or urea >7 mmol/L) • **R**espiratory rate: ≥30 breaths per minute • **B**lood pressure: Systolic <90 mmHg OR Diastolic ≤60 mmHg • Age **65** years or older The maximum score is 5. Higher scores indicate greater pneumonia severity and mortality risk.
Clinical Considerations
- •CURB-65 was validated for community-acquired pneumonia (CAP) in adults
- •Clinical judgment should always supplement risk scores
- •Does not account for comorbidities, immunocompromise, or social circumstances
- •May underestimate severity in young patients with significant risk factors
- •Not validated for hospital-acquired or ventilator-associated pneumonia
- •Consider lower threshold for admission in elderly or frail patients
Limitations
- •Derived from community-acquired pneumonia populations
- •Does not include radiographic findings or oxygen saturation
- •May not apply to immunocompromised patients
- •Social factors and ability to care for self not considered
- •Some patients with low scores may still require admission for other reasons
- •Urea/BUN not always immediately available in outpatient settings
Interpretation Guide
| Range | Classification | Recommendation |
|---|---|---|
| <-1 | Low Risk | Low risk of death. Outpatient treatment is likely appropriate. Consider oral antibiotics and close follow-up. |
| 1-2 | Low to Moderate Risk | Intermediate mortality risk. Consider short inpatient hospitalization or hospital-supervised outpatient treatment. Clinical judgment is essential. |
| 2-3 | Moderate Risk | Moderate mortality risk. Hospital admission is recommended. Intravenous antibiotics and monitoring indicated. |
| 3-5 | High Risk | High risk of death. Hospital admission is required. Manage as severe pneumonia. Consider ICU admission, especially if score is 4-5. |
| 5-6 | Very High Risk | Very high risk of death. ICU admission strongly recommended. Aggressive management with close monitoring required. |
Frequently Asked Questions
What is the CURB-65 score?
CURB-65 is a clinical prediction tool that assesses the severity of community-acquired pneumonia. It evaluates 5 criteria: Confusion, Urea level, Respiratory rate, Blood pressure, and age 65 or older. Each present criterion scores 1 point, with a maximum of 5 points.
When should I use CURB-65 vs PSI (Pneumonia Severity Index)?
CURB-65 is simpler and can be calculated at the bedside with fewer variables, making it practical for rapid assessment. PSI is more comprehensive and may be more accurate in some populations, but requires more data points. CURB-65 is often preferred for initial assessment due to its ease of use.
What score indicates need for hospitalization?
Scores of 0-1 generally indicate outpatient treatment is safe. A score of 2 is a gray zone where clinical judgment is important. Scores of 3-5 typically require hospital admission, with scores of 4-5 warranting ICU consideration.
Can CURB-65 be used for COVID-19 pneumonia?
While CURB-65 was validated for bacterial community-acquired pneumonia, studies have shown it can help predict outcomes in COVID-19 pneumonia. However, COVID-19 may have unique features not captured by CURB-65, so clinical judgment remains essential.
What is CRB-65?
CRB-65 is a simplified version of CURB-65 that excludes urea (U), making it useful in outpatient settings where lab work is not immediately available. It uses only Confusion, Respiratory rate, Blood pressure, and age.
References
1. Lim WS, van der Eerden MM, Laing R, et al.. Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax. 2003. doi: 10.1136/thorax.58.5.377
View Source →2. Lim WS, Baudouin SV, George RC, et al.. BTS guidelines for the management of community acquired pneumonia in adults: update 2009. Thorax. 2009. doi: 10.1136/thx.2009.121434
View Source →3. Barlow G, Nathwani D, Davey P. Validation of a modified CURB-65 score for community-acquired pneumonia. Journal of Antimicrobial Chemotherapy. 2007. doi: 10.1093/jac/dkm120
View Source →Last updated: 2025-01-15
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