SAPS II uses 17 variables (12 physiological, 3 chronic diseases, age, and admission type) to predict ICU hospital mortality. Use worst values from the first 24 hours of ICU admission. Validated across European and North American ICUs.
Critical CareICUMortality Prediction
SAPS II Calculator (Worst 24h Values)
Age & Admission Type
Physiological Variables (worst 24h)
Chronic Diseases (check all that apply)
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SAPS II Score
Mortality Equation
logit = −7.7631 + 0.0737 × SAPS II + 0.9971 × ln(SAPS II + 1)
Timing: Record worst values within the first 24 hours of ICU admission. For non-ICU patients transferred in, use the 24h window from ICU admission time.
GCS: If the patient is sedated, use the estimated pre-sedation GCS (or document as "unable to assess" and use clinical judgment).
PaO₂/FiO₂: Only score this variable if the patient is mechanically ventilated. Record 0 points if spontaneously breathing — do not score the P/F ratio regardless of hypoxaemia.
Bilirubin: μmol/L used in the original Le Gall derivation. To convert from mg/dL: × 17.1.
Chronic disease: Only one chronic disease category is scored (the highest-scoring applies). AIDS takes priority at 17 points.
SAPS II vs APACHE II: Both are validated for ICU risk stratification. SAPS II was derived from European + US data; APACHE II from US only. Neither should replace clinical judgment for individual patient management.
References
Le Gall JR, et al. A new Simplified Acute Physiology Score (SAPS II) based on a European/North American multicenter study. JAMA. 1993;270(24):2957–2963.
Moreno R, et al. SAPS 3 — From evaluation of the patient to evaluation of the intensive care unit. Intensive Care Med. 2005;31(10):1336–1344.