CURB-65

CURB-65 Pneumonia Severity Score: Validated tool for predicting 30-day mortality and guiding inpatient vs. outpatient triage.

Guidelines & Evidence

Clinical Details

Section 1

When to Use

Clinical Use

Severity assessment of community-acquired pneumonia (CAP) in the hospital.

Identifying patients who require inpatient management (ward vs. ICU).

Risk stratification for predicted 30-day mortality.

Exclusion Criteria

Not intended for use in pediatric populations or in patients with healthcare-associated pneumonia (HCAP) or aspiration pneumonia.

Section 2

Formula & Logic

Scoring variables (1 pt each)

Confusion	New onset
Urea	> 19 mg/dL
Respiratory Rate	≥ 30 breaths/min
Blood Pressure	SBP < 90 or DBP ≤ 60
Age	≥ 65 years

30-Day Mortality Risk

Score 0	0.6% risk
Score 1	2.7% risk
Score 2	6.8% risk
Score 3	14% risk
Score 4-5	27.8% risk

Section 3

Pearls/Pitfalls

Key Strengths

Extremely simple and memorable for rapid triage.

High predictive power for short-term mortality.

Better than PSI for predicting need for ICU admission.

Limitations

Does not account for comorbid conditions (e.g., CKD, CHF).

Urea measurement requires lab turnaround.

Hypoxemia (PaO2/FiO2) is not included.

Section 4

Next Steps

Management Recommendations

Score 0-1: Consider outpatient treatment.

Score 2: Hospital admission (ward).

Score 3+: Hospital admission, consider ICU for scores 4-5.

Obtain CXR, Sputum/Blood Cultures, and start appropriate antibiotics.

Complementary Calculators

PSI/PORT Score

AA Gradient

Anion Gap

Section 5

Evidence Appraisal

Primary Validation

Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study.

Lim WS et al. • Thorax. 2003;n=1,068. Derived and validated in the UK, NZ, and NL.

Section 6

Literature

British Thoracic Society

The score was developed by the British Thoracic Society (BTS) research committee to standardize the assessment and management of pneumonia.

Dr. W.S. Lim

The lead author and primary researcher behind the derivation and validation of the tool.

Last Comprehensive Review: 2026

Related Infectious Disease Tools

Aminoglycoside Extended Interval

Antibiotic Duration Guide

Antibiotic PKPD Optimisation

APACHE II Sepsis Context

ATS IDSA CAP Severity

Bacteremia Risk Shapiro

Bacterial Meningitis Score

C difficile Severity Recurrence

CAUTI Criteria

CD4 OI Risk

Have feedback about this calculator?Let us know.

CURB-65

CURB-65 Pneumonia Severity Score: Validated tool for predicting 30-day mortality and guiding inpatient vs. outpatient triage.

Guidelines & Evidence

Clinical Details

Section 1

When to Use

Clinical Use

Severity assessment of community-acquired pneumonia (CAP) in the hospital.

Identifying patients who require inpatient management (ward vs. ICU).

Risk stratification for predicted 30-day mortality.

Exclusion Criteria

Not intended for use in pediatric populations or in patients with healthcare-associated pneumonia (HCAP) or aspiration pneumonia.

Section 2

Formula & Logic

Scoring variables (1 pt each)

Confusion	New onset
Urea	> 19 mg/dL
Respiratory Rate	≥ 30 breaths/min
Blood Pressure	SBP < 90 or DBP ≤ 60
Age	≥ 65 years

30-Day Mortality Risk

Score 0	0.6% risk
Score 1	2.7% risk
Score 2	6.8% risk
Score 3	14% risk
Score 4-5	27.8% risk

Section 3

Pearls/Pitfalls

Key Strengths

Extremely simple and memorable for rapid triage.

High predictive power for short-term mortality.

Better than PSI for predicting need for ICU admission.

Limitations

Does not account for comorbid conditions (e.g., CKD, CHF).

Urea measurement requires lab turnaround.

Hypoxemia (PaO2/FiO2) is not included.

Section 4

Next Steps

Management Recommendations

Score 0-1: Consider outpatient treatment.

Score 2: Hospital admission (ward).

Score 3+: Hospital admission, consider ICU for scores 4-5.

Obtain CXR, Sputum/Blood Cultures, and start appropriate antibiotics.

Complementary Calculators

PSI/PORT Score

AA Gradient

Anion Gap

Section 5

Evidence Appraisal

Primary Validation

Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study.

Lim WS et al. • Thorax. 2003;n=1,068. Derived and validated in the UK, NZ, and NL.

Section 6

Literature

British Thoracic Society

The score was developed by the British Thoracic Society (BTS) research committee to standardize the assessment and management of pneumonia.

Dr. W.S. Lim

The lead author and primary researcher behind the derivation and validation of the tool.

Last Comprehensive Review: 2026

Related Infectious Disease Tools

Aminoglycoside Extended Interval

Antibiotic Duration Guide

Antibiotic PKPD Optimisation

APACHE II Sepsis Context

ATS IDSA CAP Severity

Bacteremia Risk Shapiro

Bacterial Meningitis Score

C difficile Severity Recurrence

CAUTI Criteria

CD4 OI Risk

Have feedback about this calculator?Let us know.

CURB-65

Confusion

Urea > 7 mmol/L

RR ≥ 30 /min

SBP < 90 or DBP ≤ 60

Age ≥ 65

Clinical Details

When to Use

Clinical Use

Exclusion Criteria

Formula & Logic

Scoring variables (1 pt each)

30-Day Mortality Risk

Pearls/Pitfalls

Key Strengths

Limitations

Next Steps

Management Recommendations

Complementary Calculators

Evidence Appraisal

Primary Validation

Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study.

Literature

British Thoracic Society

Dr. W.S. Lim

Related Infectious Disease Tools

CURB-65

Confusion

Urea > 7 mmol/L

RR ≥ 30 /min

SBP < 90 or DBP ≤ 60

Age ≥ 65

Clinical Details

When to Use

Clinical Use

Exclusion Criteria

Formula & Logic

Scoring variables (1 pt each)

30-Day Mortality Risk

Pearls/Pitfalls

Key Strengths

Limitations

Next Steps

Management Recommendations

Complementary Calculators

Evidence Appraisal

Primary Validation

Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study.

Literature

British Thoracic Society

Dr. W.S. Lim

Related Infectious Disease Tools