BISAP score
Early in-hospital mortality risk in acute pancreatitis (first 24 h)
Sources last checked: 2026-10-13
BISAP score
Early in-hospital mortality risk in acute pancreatitis (first 24 h)
Mortality was below 1 % in the lowest-risk group of the derivation cohort.
Use data from the first 24 hours. BISAP predicts mortality; it does not replace the revised Atlanta classification of severity, which needs persistent (> 48 h) organ failure.
Interpretation
| 0–2 — lower risk | Mortality was below 1 % in the lowest-risk group of the derivation cohort. |
|---|---|
| 3–5 — higher risk | BISAP ≥ 3 was associated with organ failure, persistent organ failure and pancreatic necrosis (Singh 2009); mortality exceeded 20 % in the highest-risk group (Wu 2008). |
What is the BISAP score?
The Bedside Index for Severity in Acute Pancreatitis (BISAP) predicts in-hospital mortality from five items available within 24 hours: BUN, mental status, SIRS, age and pleural effusion. Wu, Banks and colleagues derived it in 2008 from more than 17,000 US admissions and validated it in a further 18,000.
When to use it
- Acute pancreatitis within the first 24 hours of admission
- Identifying patients at higher risk of organ failure and death early in the course
- Simple bedside alternative to APACHE II or Ranson criteria
When not to use it
- Defining severity per revised Atlanta classification (needs persistent organ failure > 48 h)
- Later in the course, after the first 24 hours
How it is calculated
| Criterion | Points |
|---|---|
| BUN > 25 mg/dL (urea > 8.9 mmol/L) | +1 |
| Impaired mental status (GCS < 15) | +1 |
| SIRS (≥ 2 of: T < 36 or > 38 °C; RR > 20 or PaCO₂ < 32 mmHg; HR > 90; WBC < 4 or > 12 ×10⁹/L or > 10 % bands) | +1 |
| Age > 60 years | +1 |
| Pleural effusion on imaging | +1 |
Clinical pearls and limitations
- Use data from the first 24 hours. BISAP predicts mortality; it does not replace the revised Atlanta classification of severity, which needs persistent (> 48 h) organ failure.
- One point each: BUN > 25 mg/dL (urea > 8.9 mmol/L), impaired mental status, SIRS, age > 60, pleural effusion.
- BISAP ≥ 3 was associated with organ failure and pancreatic necrosis in a prospective validation.
- Mortality was below 1 % in the lowest-risk group and above 20 % in the highest.
Frequently asked questions
What BISAP score is severe?
A score of 3 or more marks a higher risk of organ failure and death.
How do I convert BUN 25 mg/dL to urea?
BUN 25 mg/dL corresponds to urea of about 8.9 mmol/L (BUN mg/dL × 0.357).
BISAP, Ranson or APACHE II?
BISAP can be completed within 24 hours, whereas Ranson needs 48 hours. In the derivation study BISAP's accuracy for mortality was comparable to APACHE II with far fewer variables.
Evidence and guidelines
- Primary source: Wu BU, Johannes RS, Sun X, Tabak Y, Conwell DL, Banks PA. The early prediction of mortality in acute pancreatitis: a large population-based study. Gut 2008;57(12):1698-1703.
- Singh VK, Wu BU, Bollen TL et al. A prospective evaluation of the bedside index for severity in acute pancreatitis score. Am J Gastroenterol 2009;104(4):966-971.
Have a follow-up question?
Medelix answers clinical questions from current guidelines and studies — every statement with its source.
Ask Medelix about the BISAP scoreRelated calculators
Embed this calculatorFree to use on your website, intranet or teaching page. Copy the code below.
<iframe src="https://medelix.ai/en/embed/bisap" title="BISAP score – Medelix" width="100%" height="620" style="border:0;max-width:720px" loading="lazy"></iframe>
<p><a href="https://medelix.ai/en/calculators/bisap-score">BISAP score calculator by Medelix</a></p>For healthcare professionals and medical students. These tools support, and do not replace, clinical judgement. Always check results against the original source and your local protocols.