readmitted, a new APACHE II score is calculated. In the original research paper that described the APACHE II score, patient prognosis (specifically, predicted mortality) was computed based on the patient's APACHE II score in combination with the principal diagnosis at admission. APACHE III A method to compute a refined score known as APACHE III was published in 1991. The score was validated on the dataset from 17,440 adult medical/surgical intensive care unit (ICU) admissions at 40 US hospitals. The prognostic system of APACHE III has two options: APACHE III Score Provides an initial risk classification of severely ill hospitalized patients in defined groups. APACHE III predictive equation Adds additional variables to the APACHE III Score including the primary reason for ICU admission (from a reference list of 212 conditions classified according to etiology, major organ involved, and distinction between surgical/medical categories); age, sex, race and preexisting comorbidities; and location prior to ICU admission (operating room, recovery or emergency department, transfer or readmission from another hospital or ICU). When possible, the time between the patient's arrival at the hospital and their ICU admission is recorded. To evaluate the severity of disease 20 physiologic variables are measured, compared to 12 variables for APACHE II. APACHE III scores range from 0 to 299. APACHE IV APACHE IV, published in 2006, is the latest version. The model was developed using data from 104 intensive care units (ICUs) in 45 U.S. hospitals and could be recommended to use in U.S. ICUs. See also ASA physical status classification system Glasgow Coma Scale (used by APACHE II) References External links APACHE II calculator script in Python 3.4. (licensed under GPL 3.0) Microsoft Excel function to calculate APACHE II score Commonly used website to calculate APACHE II score with visual representation of predicted mortality Diagnostic intensive care medicine Medical scales