Ranson Criteria: Gold standard for predicting severity and mortality in acute pancreatitis. Requires 48h longitudinal assessment.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Predicting severity and mortality risk in acute pancreatitis at admission and at 48 hours.
Identifying patients who require ICU-level care or expedited imaging.
Used alongside BISAP and CTSI for multi-modality severity assessment.
Most applicable in gallstone and alcohol-related pancreatitis; less validated in other aetiology.
Section 2
Formula & Logic
At Admission (5 criteria)
Age > 55 years
WBC > 16,000/mm³
Blood glucose > 11 mmol/L (200 mg/dL)
Serum AST > 250 IU/L
Serum LDH > 350 IU/L
At 48 Hours (6 criteria)
Haematocrit fall > 10%
BUN rise > 1.8 mmol/L (5 mg/dL)
Serum calcium < 2 mmol/L (< 8 mg/dL)
PaO₂ < 60 mmHg
Base deficit > 4 mEq/L
Estimated fluid sequestration > 6 L
Mortality by Score
Criteria Met
Mortality
0–2
< 5%
3–4
~15%
5–6
~40%
7–8
100%
Section 3
Pearls/Pitfalls
Clinical Pearls
≥ 3 criteria = severe pancreatitis — triggers ICU admission and pancreatic protocol CT.
Score is assessed at two time points; admission assessment alone is insufficient.
BISAP score (5 variables, single time point) is preferred for point-of-care mortality assessment.
Ranson is less accurate in non-alcoholic pancreatitis — apply CTSI and BISAP in conjunction.
Limitation
The 48-hour assessment requires serial labs, making it impractical for rapid triage. HAPS (3 variables) identifies mild AP within 30 minutes of presentation.
Section 4
Next Steps
Clinical Actions
01
< 3 criteria: Moderate-severity management — IV fluids, analgesia, keep NBM initially, monitor for 48–72h.
02
≥ 3 criteria: Severe AP — urgent CT pancreas (72h optimal), ICU or HDU admission, nutrition team input, surgical/hepatobiliary review.
03
Correct calcium, glucose, and PaO₂ abnormalities aggressively.
04
Identify and treat precipitating cause (gallstones → ERCP ± cholecystectomy; alcohol counselling).
Section 5
Evidence Appraisal
Primary Reference
Prognostic signs and the role of operative management in acute pancreatitis
Developed by John Ranson and colleagues at the Bellevue Hospital Center, New York University, and published in Surgery, Gynecology & Obstetrics in 1974. The criteria were derived from retrospective analysis of 100 consecutive patients with acute pancreatitis and subsequently validated in a prospective series of 200 patients. The 11-criterion structure was designed to identify which patients were at high risk of death and required intensive monitoring.
Historical Legacy & Limitations
Ranson Criteria were the dominant pancreatitis severity score for over two decades. The requirement for serial 48-hour assessment and the exclusion of gallstone-specific criteria in the original form led to the development of alternatives including BISAP (2008) and HAPS (2009). The Revised Atlanta Classification (2013) has now superseded Ranson for severity classification, though Ranson remains widely taught and used in clinical practice.
