Ranson Criteria Calculator

Score the 5 admission and 6 forty eight hour Ranson criteria to estimate severity and mortality in acute pancreatitis.

What it does

The Ranson criteria estimate the severity of acute pancreatitis. They were published in the 1970s and remain a familiar teaching tool even though newer scores and imaging classifications are now common. The original set uses five values at admission and six values during the first 48 hours.

The admission criteria are age above 55, white blood cell count above 16,000 per cubic millimeter, blood glucose above 200 mg/dL, serum LDH above 350 IU/L, and serum AST above 250 IU/L. The 48 hour criteria are a hematocrit drop greater than 10 percent, a blood urea nitrogen rise greater than 5 mg/dL, serum calcium below 8 mg/dL, arterial oxygen pressure below 60 mmHg, base deficit greater than 4 mEq/L, and fluid sequestration greater than 6 liters.

Each criterion is worth 1 point. A total of 0 to 2 points is mild, with mortality often quoted at 0 to 3 percent. A total of 3 to 4 points is moderate, with mortality around 15 percent. A total of 5 to 6 points is severe, with mortality around 40 percent. A total of 7 to 11 points is also severe, with mortality near 100 percent in the original reports.

The two phase structure matters. A patient who looks well on admission can accumulate points over the next two days as fluids shift, calcium falls, and oxygen requirements rise. The score is therefore a reason to reassess, not a one time label. It also explains why the same patient can have a low score in the emergency department and a high score on the ward.

Ranson was derived before modern fluid resuscitation, early enteral feeding, and step up endoscopic drainage. Its mortality estimates come from older cohorts and may overstate risk in current practice. It also does not distinguish interstitial from necrotizing pancreatitis. Use it with current imaging, organ failure assessment, and the patient's response to early treatment.

How to use

1. Confirm the diagnosis of acute pancreatitis with typical pain, lipase or amylase elevation, and imaging when needed.
2. At admission, check age, white blood cell count, glucose, LDH, and AST. Score 1 point for each value above the threshold.
3. At 48 hours, check the hematocrit change, blood urea nitrogen change, calcium, arterial oxygen, base deficit, and fluid sequestration. Score 1 point for each positive criterion.
4. Add the admission points and the 48 hour points separately, then add both for the total.
5. Match the total to the severity and mortality bands. Reassess if the clinical course changes.
6. Use the result with organ failure assessment, imaging, and the local pancreatitis pathway. Do not use it to decide surgery on its own.

Formula

Admission criteria

Age above 55, WBC above 16,000 per mm3, glucose above 200 mg/dL, LDH above 350 IU/L, AST above 250 IU/L.

48 hour criteria

Hematocrit drop above 10 percent, BUN rise above 5 mg/dL, calcium below 8 mg/dL, PaO2 below 60 mmHg, base deficit above 4 mEq/L, fluid sequestration above 6 L.

Total

Sum of all positive criteria, from 0 to 11.

The thresholds are specific to the original Ranson criteria. Do not substitute other cutoffs from different pancreatitis scores. The hematocrit and BUN criteria use the change from admission, not a single value. Fluid sequestration is the difference between fluid intake and output, including insensible losses in some protocols. The mortality bands are historical estimates, not individualized predictions.

Worked example

Reference table

Limits

• The score needs 48 hours of data, so it cannot guide the first hours of care on its own.
• The mortality estimates come from older cohorts and may not match modern treatment.
• It does not separate interstitial from necrotizing pancreatitis or replace CT severity scoring.
• Age and some laboratory thresholds are fixed, so the score may perform differently in younger or older populations.

Common mistakes

• Scoring the hematocrit or BUN as a single value instead of the change from admission.
• Using a glucose threshold of 180 mg/dL or another cutoff from a different score.
• Adding admission and 48 hour points twice, or counting the same criterion in both phases.
• Treating a score of 4 as a reason for immediate surgery. Surgery timing depends on infection and clinical course.
• Ignoring organ failure, imaging, and the response to fluids because the total looks low.

Try it yourself

Quick checks. Answers sit tucked under each question.

Questions

Sources

• Original Ranson prognostic signs study in Surgery, Gynecology and Obstetrics
• Utility of Ranson score and CT severity index in acute pancreatitis

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