M+QuickMedCalc
Educational reference only. Not a diagnostic tool. See full disclaimer.
Emergency Medicine & Critical CareBISAP

BISAP Score Calculator for Acute Pancreatitis

Record the five-item adult BISAP early prognostic score from the first 24 hours of an established acute-pancreatitis hospitalization.

Content updated: View sources

QuickMedCalc is developed and maintained by an independent developer. Medical content is not independently reviewed by a physician.

Formula and medical content are based on the references listed on this page. See sources, About, and Sources and Review Process.

Confirm assessment scope first

This page is for an adult admission in which acute pancreatitis has already been established clinically; the calculator does not diagnose it.

The five findings may come from different records in that window, but do not mix admissions, later deterioration, or post-treatment time points.

First-24-hour BISAP inputs

Choose Available only when a highest documented BUN in mg/dL is available for this admission window.

Original BISAP uses disorientation or a more severe abnormality. GCS <15 may support documentation, but this page does not calculate a complete GCS; sedation, intubation, drugs, baseline cognition, language, or neurologic disease may prevent reliable assessment.

Classic SIRS criteria: temperature >38°C or <36°C; heart rate >90/min; respiratory rate >20/min or PaCO₂ <32 mmHg; WBC >12,000/mm³, <4,000/mm³, or >10% immature forms. This page records only the external aggregate.

Enter completed age as a whole number; BISAP awards one point only when age is greater than 60 years.

Use documented chest radiography, CT, or other qualifying imaging in the first 24 hours. No imaging is not the same as no effusion.

About

BISAP is Wu’s 2008 five-item early prognostic score for adults with an established acute pancreatitis hospitalization. It uses the first 24 hours of the same admission: BUN, impaired mental status, classic SIRS status, completed age, and pleural effusion. It is a population-derived prognostic ranking tool, not a diagnosis of pancreatitis, a personal mortality probability, a Revised Atlanta severity class, or a treatment or level-of-care rule. [1, 2]

This page records only the values explicitly submitted by the user. It does not read a chart, calculate a full GCS or SIRS assessment, interpret imaging, classify organ failure, or choose fluids, nutrition, antibiotics, ERCP, surgery, monitoring, or ICU care. ACG 2024 emphasizes ongoing clinical assessment because a score or imaging result alone is not enough to predict moderately severe or severe acute pancreatitis. [3, 4, 5]

Formula

BISAP = BUN (>25 mg/dL) + impaired mental status + classic SIRS (≥2) + age (>60 years) + pleural effusion; total 0–5. [1]
All five inputs belong to the same adult hospitalization’s first 24 hours. Any unavailable component withholds the total rather than becoming zero. [1, 4]

Interpretation

These static historical proportions are shown for context from specific derivation, validation, and comparison cohorts; no row is highlighted and no proportion is attached to an individual result. [1, 2, 3]

Historical in-hospital mortality proportions by BISAP score
BISAP scoreObserved historical proportion
0–10.1–0.7%
21.9–2.1%
35.3–8.3%
412.7–19.3%
522.5–26.7%

The observed ranges are not current personal probabilities. A score of ≥3 is a common research threshold, not an automatic ICU, treatment, admission, or discharge rule; meta-analysis found limited sensitivity, so a lower score cannot exclude severe disease or death. ACG 2024 states that scoring systems or imaging alone are insufficient to predict who will develop moderately severe or severe disease. [4, 7, 8]

Revised Atlanta context — not calculated

Revised Atlanta requires at least two of characteristic abdominal pain, serum lipase or amylase at least three times the upper limit, and characteristic imaging. Its mild, moderately severe, and severe categories depend on organ-failure duration and local or systemic complications; persistent organ failure is more than 48 hours. BISAP cannot generate those categories. [4, 5]

BISAP criteria, first-24-hour boundaries, and clinical limits

Five BISAP criteria

Each item contributes one point only when it is assessed in the qualifying first-24-hour record. The page accepts the existing aggregate inputs and does not infer missing findings. [1]

Five BISAP criteria and one-point definitions
CriterionOne-point definitionSubmitted inputBoundary or limitation
BUN>25 mg/dLAvailability plus BUN mg/dL25 exactly is 0; no urea conversion
Impaired mental statusPresentPresent, absent, or not assessableGCS <15 may support documentation, but the page does not calculate GCS
Classic SIRSAt least two criteriaExternal aggregate statusInsufficient data is unavailable, not negative
Completed age>60 yearsCompleted integer years60 exactly is 0; 61 is 1
Pleural effusionPresent on qualifying imagingPresent, absent, or not assessedNo imaging does not establish absence

Wu’s original adult model used the first 24 hours and a total from 0 to 5; impaired mental status is a clinical observation, not a new GCS calculator. [1]

Classic SIRS within BISAP

Classic SIRS background uses temperature >38°C or <36°C, heart rate >90/min, respiratory rate >20/min or PaCO₂ <32 mmHg, and WBC >12,000/mm³, <4,000/mm³, or >10% immature forms. At least two satisfy the historical aggregate item. This page records an external first-24-hour assessment; it does not calculate the four inputs. SIRS is not synonymous with infection and is not the modern Sepsis-3 diagnosis. [1, 6]

Classic SIRS criteria used as BISAP background
Classic itemThreshold
Temperature>38°C or <36°C
Heart rate>90/min
Respiratory / PaCO₂>20/min or PaCO₂ <32 mmHg
White-cell count>12,000/mm³, <4,000/mm³, or >10% immature forms

What the calculator actually does

  1. Confirms an adult established acute-pancreatitis hospitalization.
  2. Confirms the same hospitalization’s first 24-hour window.
  3. Reads BUN availability and value, mental-status assessment, external SIRS aggregate, completed age, and pleural-effusion assessment.
  4. Adds one point for each present criterion using the frozen implementation.
  5. Withholds the total when any component is unavailable, while retaining a five-item audit.

It does not read records or images, calculate GCS or SIRS, diagnose pancreatitis, classify organ failure, generate Revised Atlanta severity, calculate APACHE II/Ranson/CTSI, or choose treatment or care location. [1, 4]

BISAP and related acute-pancreatitis frameworks

BISAP is a first-24-hour five-item early prognostic score. Revised Atlanta uses organ-failure duration and local/systemic complications; APACHE II uses broader acute physiology; Ranson has a different admission and later time structure; CTSI/mCTSI depends on imaging morphology. These frameworks answer different questions and cannot be converted into one another. [3, 4, 5]

Comparison of BISAP and acute pancreatitis frameworks
ToolTime frameMain inputsPrimary purposeWhy not interchangeable
BISAPFirst 24 hoursBUN, mental status, classic SIRS, age, pleural effusionFive-item early prognostic score; not formal severity classification
Revised AtlantaEarly and late disease phasesOrgan-failure duration and local/systemic complicationsDefines mild, moderately severe, and severe disease; not a point score
APACHE IIPhysiologic severity assessmentBroader acute physiology, age, and chronic health itemsDifferent inputs and timing; cannot be converted from BISAP
RansonAdmission and later time pointsDifferent clinical and laboratory criteriaDifferent time structure and endpoint
CTSI / mCTSIImaging-based assessmentPancreatic inflammation and necrosis imaging featuresRequires imaging morphology; not calculated here

Worked examples from the frozen implementation

  • Score 0: BUN 25, mental status absent, SIRS fewer than two, age 60, pleural effusion absent, with both confirmations true → score 0; 25 and 60 do not cross their strict thresholds.
  • BUN boundary: BUN 25.000000000000000001 with all other criteria absent → score 1; canonical decimal comparison preserves the greater-than-25 boundary.
  • Age boundary: BUN 25, age 61, and all other criteria absent → score 1.
  • All five: every criterion present and assessable → score 5, without an individual probability, ICU label, or treatment output.
  • Not calculable: BUN unavailable with other known items → no score, no /5, BUN marked unavailable, and the other four criteria retained for audit.

These examples are generated from the frozen calculator contract and demonstrate arithmetic or availability boundaries, not patient-level predictions. [1, 2]

Evidence, validation, and threshold limitations

Wu derived the score in a large population-based adult cohort, Singh prospectively evaluated it, and Gao’s systematic review and meta-analysis summarized multiple cohorts. Their endpoints and populations are not identical: studies examine mortality, organ failure, persistent organ failure, necrosis, or Revised Atlanta severity under different definitions. A common research threshold is ≥3, but sensitivity is not sufficient to use a lower score to rule out severe disease or death. The 2015 Gao publication is cited together with its formal Correction; no claim here guesses what the Correction changed or says it changed the BISAP algorithm. [1, 2, 7, 8]

Revised Atlanta and current guideline context

Acute pancreatitis diagnosis is a separate clinical process. Revised Atlanta uses at least two diagnostic features and defines mild, moderately severe, and severe disease by organ-failure duration and complications, including persistent organ failure beyond 48 hours. ACG 2024 emphasizes initial risk assessment plus ongoing clinical evaluation; neither BISAP nor imaging alone replaces that process. [4, 5]

Important limitations

Interpretation is limited by evolving organ failure, hemodynamics, hypoxemia or respiratory support, renal dysfunction and changing BUN, fluid treatment, pancreatic necrosis, local or systemic complications, obesity, comorbidity, etiology, infection, cholangitis, nutrition tolerance, pain, vomiting, oral intake, late deterioration, pregnancy, childhood, transfer, delayed presentation, mixed admissions, sedation, intubation, confounded mental status, and missing imaging. A low score cannot exclude later deterioration; a high score cannot decide ICU or treatment. Do not wait for an online calculator in an unstable patient. [2, 4, 5]

References

  1. 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. PMID 18519429. DOI 10.1136/gut.2008.152702.
  2. Singh VK, Wu BU, Bollen TL, et al. A prospective evaluation of the bedside index for severity in acute pancreatitis score in assessing mortality and intermediate markers of severity in acute pancreatitis. Am J Gastroenterol. 2009;104(4):966–971. PMID 19293787. DOI 10.1038/ajg.2009.28.
  3. Papachristou GI, Muddana V, Yadav D, et al. Comparison of BISAP, Ranson's, APACHE-II, and CTSI scores in predicting organ failure, complications, and mortality in acute pancreatitis. Am J Gastroenterol. 2010;105(2):435–441. PMID 19861954. DOI 10.1038/ajg.2009.622.
  4. Tenner S, Vege SS, Sheth SG, et al. American College of Gastroenterology Guidelines: Management of Acute Pancreatitis. Am J Gastroenterol. 2024;119(3):419–437. PMID 38857482. PMCID PMC13221274. DOI 10.14309/ajg.0000000000002645.
  5. Banks PA, Bollen TL, Dervenis C, et al. Classification of acute pancreatitis—2012: revision of the Atlanta classification and definitions by international consensus. Gut. 2013;62(1):102–111. PMID 23100216. DOI 10.1136/gutjnl-2012-302779.
  6. Bone RC, Balk RA, Cerra FB, et al. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. Chest. 1992;101(6):1644–1655. PMID 1303622. DOI 10.1378/chest.101.6.1644.
  7. Gao W, Yang H-X, Ma C-E. The Value of BISAP Score for Predicting Mortality and Severity in Acute Pancreatitis: A Systematic Review and Meta-Analysis. PLoS One. 2015;10(6):e0130412. PMID 26091293. DOI 10.1371/journal.pone.0130412.
  8. Gao W, Yang H-X, Ma C-E. Correction: The Value of BISAP Score for Predicting Mortality and Severity in Acute Pancreatitis: A Systematic Review and Meta-Analysis. PLoS One. 2015;10(10):e0142025. PMID 26513663. DOI 10.1371/journal.pone.0142025.

FAQ

Related Calculators

Classic SIRS

Count the classic 1992 adult systemic inflammatory response criteria from submitted measurements, without diagnosing sepsis.

APACHE II

Reproduce the 1985 adult general-ICU APACHE II severity score from worst first-24-hour physiology, age and defined chronic-health points.

Classic SOFA-1

Calculate the original 1996 Classic SOFA-1 score from the worst eligible values in one defined 24-hour window, with an optional comparable-baseline change.

Disclaimer

Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.