APACHE II Score Calculator

About this calculator

APACHE II (Acute Physiology and Chronic Health Evaluation II) is a widely used ICU severity-of-illness score built from three components measured over the worst values in a patient's first 24 hours: an Acute Physiology Score from 12 variables (temperature, mean arterial pressure, heart rate, respiratory rate, oxygenation, arterial pH, serum sodium, potassium and creatinine, hematocrit, white blood cell count, and Glasgow Coma Scale), plus points for age and for chronic health conditions. The components sum to a score from 0 to 71, which correlates with the risk of in-hospital mortality.

This calculator totals those points and estimates hospital mortality risk from the result. Intensivists and ICU nurses use APACHE II at admission to gauge how sick a patient is and guide the intensity of monitoring, while hospital quality-improvement teams and clinical researchers use it to risk-adjust outcomes when comparing mortality rates across ICUs or clinical trial arms.