What is the BISAP score?

BISAP (Bedside Index for Severity in Acute Pancreatitis) is a 5-point scoring system that predicts in-hospital mortality and severe disease risk in patients presenting with acute pancreatitis. It was developed to provide a simple, rapidly calculable alternative to Ranson criteria and APACHE II. Each letter represents one criterion: BUN >25, Impaired mental status, SIRS, Age >60, Pleural effusion.

How do I calculate the BISAP score?

Score one point for each criterion present at admission or within 24 hours: BUN >25 mg/dL, impaired mental status (disorientation/lethargy/stupor/coma), SIRS (≥2 of: temp >38°C or 90, RR >20, WBC >12k or 60 years, pleural effusion on imaging. Total score ranges 0–5.

What does each BISAP score mean for mortality prediction?

BISAP 0: in-hospital mortality <0.1%. BISAP 1: approximately 0.1–0.5%. BISAP 2: approximately 1–2%. BISAP 3: approximately 5–10%. BISAP 4: approximately 10–15%. BISAP 5: approximately 15–20%+. Score ≥3 represents a clinically significant threshold associated with substantial organ failure risk and should prompt ICU-level monitoring.

What are the SIRS criteria used in BISAP scoring?

SIRS (Systemic Inflammatory Response Syndrome) for BISAP requires ≥2 of four criteria: (1) Temperature >38°C or 90 beats per minute; (3) Respiratory rate >20 breaths per minute; (4) White blood cell count >12,000/µL or 10% band forms. SIRS is present in most patients with acute pancreatitis at presentation; persistent SIRS >48 hours defines systemic severity.

What is the role of fluid resuscitation in acute pancreatitis?

Aggressive early IV fluid resuscitation is the cornerstone of acute pancreatitis treatment. It prevents hemoconcentration (elevated BUN, rising hematocrit), reduces pancreatic ischemia, and limits progression to necrotizing pancreatitis. Goal-directed resuscitation targets: urine output >0.5 mL/kg/hr, BUN decrease over 24 hours, heart rate <100, mean arterial pressure 65–85 mmHg. Over-resuscitation causes abdominal compartment syndrome — reassess fluid needs every 6 hours.

When should CT be obtained in acute pancreatitis?

CT abdomen/pelvis with IV contrast (CECT) is not needed in mild pancreatitis with expected clinical improvement. Indications for CECT: (1) Diagnostic uncertainty; (2) Clinical deterioration after 48–72 hours of appropriate treatment; (3) Suspected pancreatic necrosis (fever persisting >5–7 days, clinical deterioration); (4) Suspected infected necrosis (consideration of drainage). Early CT (<48 hours) underestimates necrosis — wait until 72 hours for optimal assessment.

What causes acute pancreatitis?

Most common causes: gallstones (40–50%) — biliary sludge or stones obstruct the pancreatic duct; alcohol use (25–35%) — direct pancreatic toxicity; hypertriglyceridemia (1–5%) — triglycerides >1,000 mg/dL; ERCP-related pancreatitis (2–5%); drugs (1–2%: azathioprine, valproic acid, tetracycline, didanosine); autoimmune pancreatitis (IgG4-related); and idiopathic (10–15%). Identifying the etiology guides secondary prevention.

What is pancreatic necrosis and how is it managed?

Pancreatic necrosis is death of pancreatic parenchyma and/or peripancreatic tissue, present in approximately 20% of acute pancreatitis cases. Sterile necrosis is managed conservatively with prolonged supportive care. Infected necrosis (fever, leukocytosis, gas in necrotic cavity on CT) requires intervention: step-up approach beginning with percutaneous drainage, followed by endoscopic or surgical necrosectomy if drainage fails. Antibiotics (carbapenems or quinolones + metronidazole) are used for suspected infected necrosis only.

When is ERCP indicated in acute pancreatitis?

ERCP (endoscopic retrograde cholangiopancreatography) is indicated in gallstone pancreatitis with: (1) Concurrent acute cholangitis (urgent ERCP within 24 hours); (2) Persistent biliary obstruction (rising bilirubin, dilated CBD) — ERCP within 24–72 hours. ERCP is NOT indicated in uncomplicated gallstone pancreatitis without cholangitis or persistent obstruction — it does not improve outcomes and risks procedure-related pancreatitis worsening. Cholecystectomy during same admission is standard after recovery.

Online Medical Tools — BISAP Score

Printed on 9/3/2026

For informational purposes only. This is not medical advice.

Gastroenterology

BISAP Score

The BISAP score is a bedside risk stratification tool for acute pancreatitis. It assigns one point each for BUN >25 mg/dL, impaired mental status, SIRS, age >60 years, and pleural effusion. Higher scores are associated with increased risk of severe disease, organ failure, and mortality.

Formula: BISAP = sum of 5 binary variables (BUN >25, altered mental status, SIRS, age >60, pleural effusion), total 0-5.

BUN > 25 mg/dL

Impaired mental status (GCS < 15)

SIRS present

Age > 60 years

Pleural effusion on imaging

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How It Works

Score five criteria at admission or within the first 24 hours

BISAP must be calculated within 24 hours of admission, as it captures admission-based severity — not delayed clinical evolution. Assess five binary criteria: (1) BUN >25 mg/dL from the basic metabolic panel; (2) Impaired mental status (disorientation, lethargy, stupor, or coma — GCS <15 captures this in most settings); (3) SIRS (systemic inflammatory response syndrome) — requires 2 or more of: temperature >38°C or <36°C, heart rate >90 bpm, respiratory rate >20 breaths/min, WBC >12,000 or <4,000 or >10% bands; (4) Age >60 years; (5) Pleural effusion on imaging (chest X-ray or CT).

Sum the binary criteria for a score of 0–5

Each criterion present scores one point; absent scores zero. Total the positive findings for a score from 0 (none present) to 5 (all present). Unlike Ranson criteria (11 items, split between admission and 48 hours) and APACHE II (12 continuous variables requiring a table), BISAP is entirely binary and calculable in minutes at bedside, making it the most practical tool for early pancreatitis severity assessment in busy ED and hospitalist settings.

Interpret score to guide level of care and management intensity

Risk stratification by BISAP score: 0–2 = low-to-moderate mortality risk (<1–2%); standard ward admission with IV fluids, NPO, pain management, and serial monitoring. Score 3–5 = high mortality risk (5–20%) with significant organ failure risk — strong indication for ICU-level monitoring, aggressive IV fluid resuscitation (250–500 mL/hr of lactated Ringer's preferred), early gastroenterology/critical care consultation, and preparation for potential interventional procedures. Score ≥3 patients should be closely monitored for organ failure development every 4–6 hours.

Who Uses the BISAP Score

Emergency Department Triage of Acute Pancreatitis

Emergency physicians

Calculate BISAP immediately when acute pancreatitis is diagnosed in the ED (lipase >3x ULN with compatible clinical presentation). Use BISAP ≥3 to trigger early ICU consultation, aggressive fluid resuscitation, and admission to a monitored bed rather than a general medical floor.

ICU Admission Decision

Hospitalists and intensivists

BISAP ≥3 is associated with 7–20% in-hospital mortality and carries substantial risk of organ failure (renal, pulmonary, circulatory). This threshold justifies ICU admission for hemodynamic monitoring, hourly urine output tracking, and early aggressive fluid resuscitation.

Guiding Aggressive Fluid Resuscitation Urgency

All admitting clinicians

High BISAP scores justify early aggressive isotonic fluid resuscitation. Lactated Ringer's (LR) is preferred over normal saline — the WATERFALL trial (de-Madaria et al., NEJM 2022) showed LR reduced SIRS in acute pancreatitis. BISAP ≥3 supports 250–500 mL/hr LR for the first 24 hours with hourly urine output monitoring.

Communicating Prognosis to Patients and Families

Hospitalists and gastroenterologists

BISAP provides a structured framework for family meetings: BISAP 0–2 = good prognosis expected; BISAP ≥3 = serious illness with meaningful mortality risk, possible prolonged ICU stay, and risk of complications including pancreatic necrosis.

Comparing Severity Tools — BISAP vs Ranson vs APACHE II

Clinical educators and GI fellows

Teach the practical differences: Ranson criteria uses 11 items across two time points (admission AND 48 hours), making early calculation impossible. APACHE II requires continuous variables requiring table lookup, validated in ICU settings. BISAP is 5 binary items calculable at admission — the most accessible for initial triage in non-ICU settings.

Pro Tips

BISAP is simpler and faster than Ranson criteria

Ranson criteria uses 11 items (5 at admission + 6 at 48 hours), requiring a second calculation. BISAP uses 5 binary items all assessable at initial presentation. Head-to-head validation by Singh et al. (Gastroenterology 2009) showed BISAP performed comparably to APACHE II and Ranson for predicting severe pancreatitis — with far less complexity.

SIRS requires 2 or more of 4 specific criteria — know them cold

SIRS = ≥2 of: (1) Temperature >38°C OR <36°C; (2) Heart rate >90 bpm; (3) Respiratory rate >20 breaths/min; (4) WBC >12,000/µL OR <4,000/µL OR >10% band forms. SIRS is the most complex criterion in BISAP and the most commonly mis-scored. Check all four components systematically before scoring SIRS as absent.

BUN >25 mg/dL is a key early hemoconcentration marker

Elevated BUN in acute pancreatitis reflects hemoconcentration (inadequate volume resuscitation) and systemic inflammation — both markers of severity. A BUN >25 at admission, combined with rising BUN over 24 hours despite IVF, predicts need for ICU care and mortality independently of other factors.

BISAP ≥3 patients need ICU-level monitoring

The transition from BISAP 2 to 3 represents a dramatic increase in mortality risk (~1% to ~5–10%). BISAP ≥3 should trigger ICU consultation regardless of initial hemodynamic stability. Severe pancreatitis can deteriorate rapidly — a patient who appears stable at admission may develop third-spacing and circulatory failure within 12–24 hours.

Lactated Ringer's preferred over normal saline for acute pancreatitis resuscitation

The WATERFALL randomized controlled trial (de-Madaria et al., NEJM Evidence 2022) demonstrated that lactated Ringer's significantly reduced SIRS compared to normal saline (9% vs 18% at 24 hours) without increasing fluid overload. LR should be the default isotonic resuscitation fluid in acute pancreatitis, particularly in high-BISAP patients where SIRS reduction is a priority.

CT severity index (CTSI) is needed if clinical deterioration or to assess necrosis

BISAP predicts mortality from clinical variables but cannot assess local complications. Contrast-enhanced CT is required for pancreatic necrosis assessment (Balthazar/CTSI scoring). Obtain CT if: clinical deterioration despite 48–72 hours of treatment, suspected infected necrosis (fever + leukocytosis beyond 5–7 days), or if diagnosis is uncertain. Avoid CT in the first 48–72 hours unless absolutely necessary — early imaging often underestimates necrosis.

Gallstone pancreatitis: ERCP if cholangitis or biliary obstruction present

In gallstone pancreatitis (elevated bilirubin, ALP, dilated CBD on ultrasound), urgent ERCP is indicated if concurrent cholangitis (Charcot's triad: fever, jaundice, RUQ pain) or biliary obstruction is present. ERCP within 24–72 hours in gallstone pancreatitis without cholangitis does not improve outcomes (Oria et al., NEJM 2007). Cholecystectomy during same hospitalization (once pancreatitis resolves) prevents recurrence.

Early enteral nutrition within 24–48 hours in severe pancreatitis

NPO is appropriate initially for severe pancreatitis but prolonged fasting worsens outcomes. The PYTHON and other trials support early (within 24–48 hours) enteral feeding via nasojejunal tube in severe acute pancreatitis (BISAP ≥3). Early enteral nutrition reduces infections, organ failure, and length of stay compared to parenteral nutrition or prolonged NPO.

BISAP underestimates severity in necrotizing pancreatitis

BISAP was validated for predicting in-hospital mortality from clinical variables, but it does not directly assess local complications. Necrotizing pancreatitis (necrosis >30% of pancreatic parenchyma) is associated with 15–20% mortality even in patients who score relatively low on BISAP. Any patient with suspected severe pancreatitis (BISAP ≥2) who fails to improve in 48–72 hours should have contrast-enhanced CT to assess for necrosis.

Common Questions About Your Results

SIRS requires two or more of four criteria: (1) Temperature >38°C or <36°C; (2) Heart rate >90 bpm; (3) Respiratory rate >20 breaths/min; (4) WBC >12,000/µL or <4,000/µL or >10% bands. Check all four systematically at the time of assessment. SIRS is the most commonly mis-scored BISAP criterion. Note that SIRS criteria should be scored at the time of assessment — not projected from prior values.

BUN may be normal or only mildly elevated in early mild gallstone pancreatitis, particularly in well-hydrated patients presenting quickly. In this scenario, BISAP scores 0 on the BUN criterion and may underestimate severity if other criteria are also absent. BISAP performs best when all five criteria are systematically checked. If clinical concern remains high despite low BISAP, serial BUN measurements over 24 hours (rising BUN = worsening) and clinical reassessment remain essential.

BISAP does not assess local pancreatic complications. It predicts in-hospital mortality from systemic clinical variables but cannot determine pancreatic necrosis, pseudocyst formation, or infected necrosis. For local complication assessment, contrast-enhanced CT (Balthazar score / CT Severity Index) is required. Obtain CT if a patient deteriorates beyond 48–72 hours, develops fever beyond 5–7 days, or if the diagnosis is uncertain.

BISAP scoring for pleural effusion requires radiographic documentation — either chest X-ray or CT. If chest imaging has not been performed at the time of initial BISAP calculation, score pleural effusion as absent (0) and note the limitation. If subsequent imaging reveals a pleural effusion, rescore BISAP accordingly. In high-risk patients (BISAP ≥2 without imaging), consider obtaining chest X-ray or CT abdomen/pelvis as part of the initial workup.

Evidence-Based Methodology

BISAP was developed by Wu et al. (Am J Gastroenterol 2008) in 17,992 hospital admissions for acute pancreatitis across 16 US hospitals. Score ≥3 had 7.4% in-hospital mortality vs 0.1% for score 0. Externally validated by Singh et al. (Gastroenterology 2009), who found BISAP comparable to APACHE II for predicting severe pancreatitis and organ failure. ACG Clinical Guidelines for the Management of Acute Pancreatitis (Tenner et al., Am J Gastroenterol 2013) recommend BISAP for early severity assessment. Lactated Ringer's superiority demonstrated by de-Madaria et al. (NEJM Evidence 2022).

Clinical Content Trust

Last reviewed:: April 21, 2026
Guideline version:: General evidence framework v2026.04
Source set version:: Primary-source set v1

How to Interpret Your Result

Higher BISAP scores indicate higher risk for severe acute pancreatitis outcomes and should prompt closer monitoring and reassessment.

When to Use This Tool

Use this tool in confirmed or suspected acute pancreatitis to support early triage and level-of-care planning.

Limitations

BISAP is a prognostic aid, not a treatment algorithm. Performance can vary by population and care setting, and serial clinical reassessment remains essential.

For related assessments, see Rockall Score, AIMS65 and MELD Score.

Disclaimer: This tool is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about your health.

Changelog

April 21, 2026 · trust-baseline
Clinical trust metadata enabled for this tool page with structured review/version fields.

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Frequently Asked Questions

Ranson criteria uses 11 items split between admission (5 items) and 48 hours (6 items) — it cannot be completed at initial presentation. BISAP uses 5 binary items all calculable at admission, making it far more practical for early triage. Singh et al. (Gastroenterology 2009) validated BISAP against Ranson and APACHE II and found comparable discriminative ability for severe pancreatitis with significantly less complexity.

Acute pancreatitis is inflammation of the pancreas typically caused by gallstones (40–50%) or alcohol use (25–35%), with other causes including hypertriglyceridemia, drugs, ERCP, autoimmune conditions, and idiopathic causes. Diagnosis requires two of three: (1) typical abdominal pain (epigastric, radiating to back); (2) serum lipase or amylase ≥3x upper limit of normal; (3) characteristic imaging findings. Most (80%) cases are mild and self-limiting; 20% develop severe pancreatitis.

Cornerstone treatment: (1) Aggressive IV fluid resuscitation — lactated Ringer's 250–500 mL/hr for the first 24–48 hours (LR preferred over NS per WATERFALL trial 2022). (2) Pain management — IV opioids as needed (hydromorphone or fentanyl). (3) NPO initially, transitioning to early enteral nutrition within 24–48 hours in severe cases. (4) ICU admission for BISAP ≥3 or organ failure. (5) Antibiotics only if infected necrosis is suspected — not prophylactically.