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BISAP Score for Acute Pancreatitis Mortality

BISAP (0–5) predicts in-hospital mortality in acute pancreatitis within the first 24 hours: one point each for BUN >25 mg/dL, impaired mental status, SIRS, age >60 and pleural effusion. A score ≥3 marks substantially increased mortality.

BUN / urea (mg/dL or mmol/L)
Impaired mental status (GCS <15, disorientation) (yes/no, +1)
SIRS (≥2 of: T <36 or >38 °C, HR >90, RR >20 or PaCO₂ <32, WBC <4 or >12) (yes/no, +1)
Age (years)
Pleural effusion on imaging (yes/no, +1)

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Interpretation

Result	Meaning
0	Mortality <1%
1–2	Low–intermediate
≥ 3	High risk; mortality ranges to >20% at 5

Formula

One point each within 24 h: BUN >25 mg/dL (urea >8.9 mmol/L) · Impaired mental status · SIRS · Age >60 · Pleural effusion

Clinical pearls

Designed to be scored within the first 24 hours, before Ranson's 48-hour criteria are available.
Persistent SIRS beyond 48 h is itself a strong predictor of organ failure.

Examples

bisap bun 32 confused sirs age 70 pleural effusion BISAP for a 45 year old with BUN 15, alert, no SIRS, no effusion bisap urea 10 mmol/L 65 yo sirs no effusion alert

FAQ

What BISAP score is severe?

A BISAP score of 3 or more is associated with a substantially higher risk of death and organ failure.

Evidence

Wu BU et al. The early prediction of mortality in acute pancreatitis: a large population-based study. Gut 2008;57:1698–703.

Hepatology & GI · Reviewed 2026-10-14 · Methodology