Calculate the CURB-65 score for community-acquired pneumonia severity assessment. Determine 30-day mortality risk and recommended disposition.
The CURB-65 Pneumonia Severity Score Calculator is a validated clinical tool for assessing the severity of community-acquired pneumonia (CAP) and determining the appropriate level of care. Developed by Lim et al. (2003) based on a study of over 1,000 patients at 3 UK hospitals, CURB-65 uses five easily assessed clinical parameters to predict 30-day mortality and guide disposition decisions.
The acronym CURB-65 stands for: Confusion (new-onset), Urea (BUN >19 mg/dL or >7 mmol/L), Respiratory rate (≥30/min), Blood pressure (SBP <90 or DBP ≤60), and age ≥65. Each criterion scores one point, yielding a total from 0 to 5. Patients scoring 0–1 have 30-day mortality under 3% and can typically be treated at home. Scores of 2 warrant hospital admission, while scores of 3–5 indicate severe pneumonia requiring ICU consideration.
This calculator auto-calculates criteria from entered vital signs and labs, provides both CURB-65 (with BUN) and CRB-65 (without lab work, for outpatient settings), and includes mortality data, disposition recommendations, and a criteria breakdown table.
Pneumonia is a leading cause of hospitalization and death worldwide. CURB-65 provides rapid, evidence-based severity stratification that helps clinicians avoid both unnecessary admissions (costly, exposes low-risk patients to hospital-acquired infections) and premature discharges (potentially fatal in high-risk patients). The British Thoracic Society recommends CURB-65 as the primary severity assessment for CAP.
CURB-65 Score (0–5): C = Confusion (new mental confusion) → 1 point U = Urea (BUN > 19 mg/dL / 7 mmol/L) → 1 point R = Respiratory rate ≥ 30/min → 1 point B = Blood pressure (SBP < 90 or DBP ≤ 60) → 1 point 65 = Age ≥ 65 years → 1 point 30-Day Mortality by Score: 0: 0.7%, 1: 2.1%, 2: 9.2%, 3: 14.5%, 4: 40%, 5: 57%
Result: CURB-65 Score: 5/5 — Very High Risk (57% 30-day mortality)
All 5 criteria are met: age 72 ≥ 65 (1), new confusion (1), BUN 25 > 19 (1), RR 32 ≥ 30 (1), SBP 85 < 90 (1). Score = 5 indicates 57% 30-day mortality. ICU admission is strongly recommended with aggressive management including early antibiotics, fluid resuscitation, and consideration of vasopressors.
The original study by Lim et al. analyzed 1,068 patients from 3 UK hospitals, identifying these 5 factors as independent predictors of 30-day mortality. The score was subsequently validated in multiple international cohorts totaling over 12,000 patients, confirming its discriminatory power (area under ROC curve 0.73–0.80) and practical utility in clinical decision-making.
Score 0–1 (Low risk, <3% mortality): Consider home treatment with oral antibiotics (amoxicillin or doxycycline), adequate hydration, and follow-up at 48 hours. Score 2 (Moderate risk, ~9% mortality): Admit to hospital ward for IV antibiotics, monitoring, and observation. Score 3–5 (High risk, 15–57% mortality): Urgent ICU admission or high-dependency unit; broad-spectrum IV antibiotics; consider vasopressors and mechanical ventilation if needed.
CURB-65 may underestimate severity in young patients with severe sepsis (who score low on age), patients with hypoxemia but normal vital signs, and immunocompromised patients. It does not account for imaging findings (multilobar involvement), laboratory markers (lactate, procalcitonin), or comorbidities. Always use clinical judgment alongside the score.
CURB-65 is a clinical prediction rule for assessing the severity of community-acquired pneumonia, developed by Lim et al. in 2003. It uses 5 easily assessed parameters (Confusion, Urea, Respiratory rate, Blood pressure, age ≥65) to predict 30-day mortality and guide disposition decisions (home, ward, or ICU).
CURB-65 should be calculated at initial presentation for all adult patients with community-acquired pneumonia. It helps determine whether the patient can be safely treated at home (score 0–1), requires hospital admission (score 2), or needs ICU-level care (score 3–5).
CRB-65 excludes the urea/BUN criterion, making it usable without lab results. It scores 0–4. CRB-65 is preferred in primary care and community settings where blood tests are not immediately available. A CRB-65 score of 0 suggests home treatment is safe.
The Pneumonia Severity Index (PSI) uses 20 variables including lab values, comorbidities, and imaging. It may be more accurate for identifying low-risk patients but is more complex. CURB-65 is simpler and preferred for initial bedside assessment. Both are recommended by IDSA/ATS guidelines.
CURB-65 was validated for bacterial community-acquired pneumonia and may underestimate severity in COVID-19 pneumonia, which often features rapid respiratory deterioration despite initially stable vital signs. COVID-specific tools (such as 4C Mortality Score) should be preferred for SARS-CoV-2 infections.
Confusion refers to new-onset mental confusion, typically assessed using the Abbreviated Mental Test Score (AMTS ≤ 8) or any new disorientation to person, place, or time. Pre-existing cognitive impairment (e.g., dementia) should not be counted unless there is acute change from baseline.