What is a CURB-65 score of 2?

A CURB-65 score of 2 indicates moderate CAP severity with approximately 9.2% 30-day mortality risk. BTS guidelines recommend hospital assessment and supervised treatment. Short inpatient admission with oral antibiotics or outpatient treatment with close follow-up in 24–48 hours may be appropriate based on clinical context.

What is the difference between CURB-65 and PSI/PORT score for pneumonia?

CURB-65 is simpler (5 criteria, scored at bedside) while PSI/PORT score is more complex (20 variables including age, comorbidities, and labs) and more accurately predicts 30-day mortality. PSI/PORT better identifies truly low-risk patients for outpatient treatment, while CURB-65 is faster and more practical in emergency settings. Both are validated CAP severity tools recommended by IDSA/ATS guidelines.

What antibiotics should be used for CAP based on CURB-65?

CURB-65 guides site of care, not antibiotic selection specifically. General guidance: CURB-65 0–1 (outpatient) → Amoxicillin 500mg–1g TID or Doxycycline 100mg BD. CURB-65 2–3 (inpatient) → Co-amoxiclav + Clarithromycin IV/oral. CURB-65 4–5 (severe, ICU) → Piperacillin-Tazobactam + Levofloxacin IV. Always follow local antimicrobial stewardship guidelines.

Does CURB-65 work for COVID-19 pneumonia?

CURB-65 can be applied to COVID-19 pneumonia to assess clinical severity, but it was not specifically designed or validated for COVID-19. COVID-19 severity may be better assessed using WHO severity criteria, CRB-65, or COVID-specific tools like the 4C Mortality Score. SpO₂ and supplemental oxygen requirement are especially important in COVID-19 but not captured by CURB-65.

Medically Reviewed · CliniqWise Clinical Advisory Board — Pulmonology & Infectious Disease Panel · Updated 2026-08-27

CURB-65 Calculator — Community-Acquired Pneumonia Severity Score

Calculate the CURB-65 score to assess community-acquired pneumonia (CAP) severity and guide outpatient vs inpatient vs ICU admission decisions.

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CURB-65 Calculator

Enter values below to calculate

Confusion (new acute altered mental status)*

Urea > 7 mmol/L (> 19 mg/dL)*

Respiratory Rate ≥ 30 breaths/min*

Blood Pressure: SBP < 90 OR DBP ≤ 60 mmHg*

Age ≥ 65 years*

This calculator is for informational and educational purposes. Results should be interpreted with clinical judgment and local guidelines.

What is the CURB-65 Score?

The CURB-65 score is a widely validated clinical severity scoring system developed by the British Thoracic Society (BTS) for assessing the severity of community-acquired pneumonia (CAP) and guiding decisions on the appropriate site of care (outpatient, inpatient, or ICU). Published by Lim et al. in 2003, the score evaluates five easily obtainable clinical parameters: Confusion (new acute altered mental status), Urea (blood urea nitrogen > 19 mg/dL / 7 mmol/L), Respiratory rate (≥ 30 breaths/min), Blood pressure (systolic < 90 mmHg or diastolic ≤ 60 mmHg), and Age ≥ 65 years. Each criterion scores 1 point for a maximum score of 5. The CURB-65 score is recommended by BTS, IDSA (Infectious Diseases Society of America), and ATS (American Thoracic Society) guidelines as the primary CAP severity tool for emergency departments and hospital wards.

CURB-65 = C (Confusion, +1) + U (Urea > 7 mmol/L, +1) + R (RR ≥ 30/min, +1) + B (BP: SBP < 90 or DBP ≤ 60, +1) + 65 (Age ≥ 65 years, +1). Score 0–1: Low severity (outpatient); Score 2: Moderate (inpatient); Score 3–5: Severe (consider ICU).

When to Use the CURB-65 Calculator

Emergency department assessment of all adult patients presenting with clinical and/or radiological evidence of community-acquired pneumonia to determine appropriate care setting.
Inpatient ward assessment to identify patients at risk of clinical deterioration requiring step-up to high-dependency unit (HDU) or ICU care.
Outpatient triage decision in primary care for patients with suspected mild CAP to safely support home management with oral antibiotics versus hospital referral.
Sepsis screening in pneumonia patients: CURB-65 ≥ 3 combined with high lactate or organ dysfunction should trigger sepsis protocols.
Clinical audit and quality improvement: CURB-65 provides a standardized, reproducible metric for measuring adherence to admission decision guidelines.

Community-Acquired Pneumonia (CAP)Pneumococcal PneumoniaAtypical PneumoniaLegionella PneumoniaCOVID-19 PneumoniaAspiration PneumoniaPneumonia-Induced Sepsis

CURB-65 Score Criteria & Point System

CURB-65 Total Score

CURB-65 = C + U + R + B + 65 (one point each, max = 5)

68-year-old with confusion, RR 32, BP 88/58, Urea 9 mmol/L = Score 5 → Severe, consider ICU.

Variables

C — Confusion (+1 point)

New acute confusion (disorientation in person, place, or time), not chronic. Abbreviated Mental Test Score (AMTS) ≤ 8 if available.

U — Urea (+1 point)

Blood urea nitrogen > 19 mg/dL (7 mmol/L). If BUN unavailable in primary care, use CRB-65 (omit U criterion).

R — Respiratory Rate (+1 point)

Respiratory rate ≥ 30 breaths per minute measured over 1 full minute.

B — Blood Pressure (+1 point)

Systolic BP < 90 mmHg OR diastolic BP ≤ 60 mmHg.

65 — Age ≥ 65 years (+1 point)

Patient age 65 years or older at time of assessment.

The CRB-65 variant (Confusion, Respiratory Rate, Blood Pressure, Age ≥ 65) omits the Urea criterion and is recommended for primary care settings where blood tests may not be immediately available. CRB-65 score ≥ 2 indicates hospitalization consideration.

CURB-65 Score Interpretation & Admission Guidelines

CURB-65 guides site-of-care decisions. BTS guidelines recommend stratifying patients into three severity groups based on 30-day mortality risk.

Range	Classification	Health Risk
0–1 (Low severity)	Low Severity — Outpatient Care	30-day mortality ~1.5%. Home treatment with oral antibiotics (amoxicillin ± macrolide). Follow-up in 48 hours.
2 (Moderate severity)	Moderate Severity — Consider Hospitalization	30-day mortality ~9.2%. Hospital-supervised oral or IV antibiotics. Short admission or enhanced outpatient monitoring.
3–4 (Severe)	Severe — Inpatient Management	30-day mortality ~22%. IV antibiotics (β-lactam + macrolide or fluoroquinolone). Admit to ward with close monitoring.
5 (Very severe)	Very Severe — ICU Assessment	30-day mortality ~57%. ICU or HDU admission. Consider vasopressors, mechanical ventilation. Intensive care team review.

CURB-65 predicts 30-day all-cause mortality risk in CAP. It should be used alongside clinical judgment, oxygenation status (SpO₂, PaO₂), chest X-ray extent, and comorbidities. Do not use CURB-65 for hospital-acquired pneumonia (HAP) or ventilator-associated pneumonia (VAP).

CURB-65 Limitations & Clinical Warnings

Not validated for hospital-acquired pneumonia (HAP), healthcare-associated pneumonia (HCAP), or ventilator-associated pneumonia (VAP). Use CURB-65 for community-acquired pneumonia only.

Urea criterion requires blood test: In primary care without immediate laboratory access, use CRB-65 (omits U criterion). CRB-65 ≥ 2 = consider hospitalization.

Does not account for all severity determinants: Oxygen saturation (SpO₂ < 92%), extent of consolidation on CXR, bilateral involvement, and comorbidities (COPD, immunosuppression, heart failure) are not included in the score but critically influence admission decisions.

May underestimate severity in young adults with CAP: Young, otherwise healthy adults may have high severity CAP without meeting multiple CURB-65 criteria due to physiological reserve.

Poor sensitivity for ICU prediction: CURB-65 alone does not reliably identify the subset of CAP patients requiring intensive care. ATS/IDSA minor and major ICU criteria provide better ICU admission guidance.

Social factors not captured: Ability to take oral medications, home support, compliance, and functional status influence whether outpatient care is safe but are not reflected in the score.

Medical Disclaimer

CURB-65 is a severity assessment aid, not a replacement for clinical judgment. All CAP management decisions must be made by qualified medical personnel integrating patient history, physical examination, laboratory values, imaging findings, and local antibiotic susceptibility patterns.

References & Citations

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. 58(5): 377–382. PMID: 12728155 | DOI: 10.1136/thorax.58.5.377
Mandell LA, Wunderink RG, Anzueto A, et al.. “IDSA/ATS Consensus Guidelines on the Management of Community-Acquired Pneumonia in Adults”. Clinical Infectious Diseases. 2007. 44(Suppl 2): S27–72. PMID: 17278083 | DOI: 10.1086/511159
British Thoracic Society (BTS). “Guidelines for the Management of Community Acquired Pneumonia in Adults: Update 2009”. Thorax. 2009. 64(Suppl 3): iii1–55. PMID: 19783532 | DOI: 10.1136/thx.2009.121434

Medically Reviewed

Reviewed by CliniqWise Clinical Advisory Board — Pulmonology & Infectious Disease Panel · Last updated: 2026-08-27 · Next review: 2027-02-27

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