BISAP Score Calculator

BISAP Score Calculator for Gastroenterology. BISAP is an early 0-5 risk index; totals at least 3 identify a higher score range. It does not assign a fixed personal mortality or substitute for repeated organ-function assessment.

For shared guidance on choosing a tool and documenting results, read the clinical calculator workflow.

How this calculator works

BISAP counts five findings in the first 24 hours: age over 60, BUN over 25 mg/dL, impaired mentation, SIRS and pleural effusion. Maximum 5. Exact age 60 and BUN 25 do not earn those points.

When to use this calculator

Use for early risk stratification in acute pancreatitis alongside repeated assessment of circulation, respiration, kidney function, and complications.

Inputs used

  • Age (completed years)
  • BUN (mg/dL; not urea mmol/L)
  • Impaired mentation (GCS below 15)
  • SIRS established by a separate complete assessment
  • Pleural effusion
  • Observation window

Clinical interpretation

BISAP is an early 0-5 risk index; totals at least 3 identify a higher score range. It does not assign a fixed personal mortality or substitute for repeated organ-function assessment.

Worked example

Fictional teaching case. Age (completed years): 61; BUN (mg/dL; not urea mmol/L): 26; Impaired mentation (GCS below 15): Yes; SIRS established by a separate complete assessment: No; Pleural effusion: Yes; Observation window: First 24 hours of presentation. Result: 4 points. Higher BISAP score range. Contributions in assessment order: 1 + 1 + 1 + 0 + 1 = 4. Historical prediction is separate from Revised Atlanta clinical severity, which depends on complications and organ failure duration. Reassess the patient; do not choose fluids, surgery or ICU care from this total alone.

Limitations and safety notes

A score of 3 is not equivalent to a fixed mortality above 15%. SIRS must be separately established and all observations assessed. Historical prediction is separate from Revised Atlanta clinical severity, which depends on complications and organ failure duration. Reassess the patient; do not choose fluids, surgery or ICU care from this total alone.

Frequently asked questions

Does BISAP itself calculate SIRS?

No. The SIRS input represents a separate clinical assessment that must already have been completed.

References

  • Primary BISAP study specifies first-24-hour timing and strict age/BUN boundaries. https://pubmed.ncbi.nlm.nih.gov/18519429/
  • ACG 2024 pancreatitis guidance: repeated assessment rather than score-only management; abstract accessed. https://pubmed.ncbi.nlm.nih.gov/38857482/

Editorial review and citation methodology

Maintained by the Quick Medical Calculator Editorial Team. Content record date: September 9, 2026. A content date is not evidence of independent clinical review. Individual clinical sign-off is not recorded on this page.

  • Prefer original validation studies for scoring systems and prediction tools.
  • Use current specialty society guidance, transplant allocation policy, public health guidance, or regulator resources when they govern clinical use.
  • Include limitations and safety notes when a calculator is population-specific, context-dependent, or unsuitable as a standalone decision tool.

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