ranson calculator

What the Ranson calculator measures

The Ranson score is a classic bedside risk tool used in acute pancreatitis. It estimates severity by counting how many predefined risk criteria are present at admission and during the first 48 hours. The higher the score, the higher the risk of complications and mortality.

Even though modern systems such as BISAP, APACHE II, and the Revised Atlanta Classification are widely used, Ranson criteria remain a useful teaching framework and can still support early risk stratification.

How to use this calculator

1) Choose pancreatitis type

Select whether the episode is gallstone pancreatitis or non-gallstone/other causes. Thresholds differ slightly between these two groups.

2) Enter admission values

• Age
• White blood cell count (WBC)
• Serum glucose
• AST
• LDH

3) Enter 48-hour values

• Hematocrit drop
• BUN increase
• Serum calcium
• Arterial oxygen (PaO₂)
• Base deficit
• Estimated fluid sequestration

Ranson criteria reference thresholds

Non-gallstone pancreatitis

• Admission: Age > 55, WBC > 16,000/mm³, glucose > 200 mg/dL, AST > 250 IU/L, LDH > 350 IU/L
• 48 hours: Hct drop > 10%, BUN rise > 5 mg/dL, calcium < 8 mg/dL, PaO₂ < 60 mmHg, base deficit > 4 mEq/L, fluid sequestration > 6 L

Gallstone pancreatitis

• Admission: Age > 70, WBC > 18,000/mm³, glucose > 220 mg/dL, AST > 250 IU/L, LDH > 400 IU/L
• 48 hours: Hct drop > 10%, BUN rise > 2 mg/dL, calcium < 8 mg/dL, PaO₂ < 60 mmHg, base deficit > 5 mEq/L, fluid sequestration > 4 L

How to interpret the score

• 0–2 points: Lower-risk course (historically ~2% mortality)
• 3–4 points: Moderate severity (historically ~15% mortality)
• 5–6 points: Severe disease (historically ~40% mortality)
• ≥7 points: Very high risk (historically very high mortality)

These percentages are historical and can differ in modern practice due to improvements in ICU care, imaging, nutrition, and intervention timing.

Clinical caveats

• The full score requires a 48-hour reassessment; early decisions should not wait for perfect scoring.
• Laboratory timing and local reference standards matter.
• Use alongside clinical findings: organ failure, hemodynamics, lactate, imaging, and trend over time.
• Scores support decisions but do not replace physician judgment.

Bottom line

The Ranson calculator is a structured way to estimate acute pancreatitis severity and communicate risk clearly. It works best when integrated with ongoing reassessment, multidisciplinary care, and evidence-based management pathways.