Normal Range for Lipase
The normal range for serum lipase is typically 5-208 U/L, though the specific upper limit of normal varies by laboratory and assay method. 1
Understanding Lipase Reference Ranges
- Laboratory variation exists: Different assays and laboratories may report slightly different normal ranges, but most use an upper limit between 200-250 U/L 1, 2
- The clinically significant threshold is three times the upper limit of normal, which is the diagnostic cutoff used for acute pancreatitis 3
Clinical Interpretation of Lipase Levels
Diagnostic Thresholds
- Lipase >3 times upper limit of normal (typically >600-750 U/L) is the standard diagnostic criterion for acute pancreatitis 3, 4
- Lipase levels >10,000 U/L have a positive predictive value of 80% for biliary pancreatitis and virtually exclude alcoholic pancreatitis (99% negative predictive value) 5
Mild Elevations (1-3 times normal)
- Elevations below three times normal can occur in non-pancreatic conditions including renal disease, appendicitis, acute cholecystitis, chronic pancreatitis, and bowel obstruction 3
- In non-pancreatic abdominal pain, lipase rarely exceeds 680 U/L (approximately 3 times normal), with a specificity of 99% when using the 3x threshold 4
Lipase vs. Amylase
- Lipase is superior to amylase for pancreatic disease: It has 94% diagnostic efficiency compared to 91% for amylase, and remains elevated longer (8-14 days vs. 3-7 days) 3, 1
- Lipase has a negative predictive value of 99.8% for excluding pancreatic injury when normal 3
- The two enzymes are highly correlated (r=0.87), making simultaneous measurement largely redundant 1
Important Clinical Caveats
- Timing matters: Lipase may not be elevated if measured within 3-6 hours of symptom onset, as it rises within 4-8 hours and peaks at 24 hours 3
- Normal lipase effectively excludes clinically significant pancreatic pathology when measured >6 hours after symptom onset 3
- Persistently elevated lipase after 10 days should raise concern for pseudocyst formation 3