CURB-65 Calculator

The CURB-65 score assigns one point for each of the following risk factors present in a patient:

• C (Confusion): Disorientation to person, place, or time, or an altered mental state.
• U (Urea): Blood urea nitrogen (BUN) level greater than 7 mmol/L (or blood urea > 19 mg/dL).
• R (Respiratory Rate): A breathing rate of 30 breaths per minute or higher.
• B (Blood Pressure): Low blood pressure defined as a systolic blood pressure below 90 mmHg or a diastolic blood pressure of 60 mmHg or less.
• 65 (Age): Being 65 years of age or older.

The total score is the sum of all individual points: Score = Confusion + Urea + Respiratory Rate + Blood Pressure + Age Score. The resulting total ranges from 0 to 5, directly correlating with recommended clinical settings and predicted 30-day mortality.

Consider a 72-year-old patient who presents to the emergency department with community-acquired pneumonia. A clinical evaluation yields the following data points:

• Age: 72 years old (Adds 1 point for being ≥ 65).
• Confusion: Alert and fully oriented (Adds 0 points).
• Urea: Blood urea nitrogen is measured at 8.2 mmol/L, which is above the 7 mmol/L threshold (Adds 1 point).
• Respiratory Rate: Measured at 24 breaths per minute, which is below the 30 breaths per minute threshold (Adds 0 points).
• Blood Pressure: Systolic BP is 115 mmHg and diastolic is 75 mmHg, both above the low hypotension thresholds (Adds 0 points).

Summing these values together yields: Score = 1 (Age) + 0 (Confusion) + 1 (Urea) + 0 (Respiratory Rate) + 0 (Blood Pressure) = 2. A total CURB-65 score of 2 suggests a moderate risk of mortality, and clinicians typically consider short inpatient hospitalization or close outpatient supervision with daily monitoring.

When utilizing the CURB-65 score in practice, keep these key factors in mind:

• Baseline Values: Always compare acute changes against the patient's known baseline mental status and chronic blood pressure readings to avoid false positives.
• Lab Timeliness: Ensure that blood urea nitrogen levels are processed rapidly, as delays in obtaining lab results can stall critical triage decisions.
• Holistic Judgment: CURB-65 is a statistical screening tool, not a replacement for expert clinical judgment. Social factors, oxygen saturation, and comorbidities should always complement the numerical score.