CURB-65 Calculator

CURB-65 is a clinical prediction rule used to support severity assessment in adults with community-acquired pneumonia. Its name identifies five criteria: new Confusion, elevated Urea, increased Respiratory rate, low Blood pressure, and age 65 years or older. Each present criterion contributes one point, so the total ranges from zero to five. A higher score is associated with greater 30-day mortality in the populations in which the rule was studied. The confusion criterion means newly altered mental status, not a longstanding cognitive condition without acute change. The biochemical criterion is blood urea above 7 mmol/L, approximately blood urea nitrogen above 19 mg/dL. Respiratory rate contributes a point at 30 breaths per minute or more. Blood pressure contributes one point if systolic pressure is below 90 mmHg or diastolic pressure is 60 mmHg or lower. Age contributes one point beginning on the sixty-fifth birthday. This implementation follows a simple additive algorithm. Scores of zero or one are grouped as low risk with a cited mortality estimate of 0.6 percent. Score two is moderate risk at 2.7 percent, score three is moderate-high risk at 6.8 percent, score four is high risk at 14 percent, and score five is very high risk at 27.8 percent. These figures are cohort estimates rather than an individualized probability, and rates can differ with population, treatment, setting, and study design. CURB-65 can help clinicians communicate risk and consider care setting, but it must not decide treatment by itself. Oxygenation, work of breathing, sepsis, organ dysfunction, imaging, comorbid illness, pregnancy, immune status, ability to take oral medication, social support, and reliable follow-up may change management regardless of score. A low score does not guarantee safety, while a high score is not a substitute for direct critical-care evaluation. The rule is designed for suspected or confirmed community-acquired pneumonia in adults. It is not validated as a self-diagnosis tool, a pediatric score, or a general measure for every respiratory infection. Measurements should come from a qualified clinical assessment, and confusion or severe breathing difficulty requires urgent attention. Anyone with blue lips, severe breathlessness, fainting, new confusion, or other signs of instability should seek emergency care rather than relying on an online result.