Normal Fecal Elastase Level
Normal fecal elastase-1 values range from 200-500 μg/g of stool, with levels above 200 μg/g indicating normal pancreatic exocrine function. 1
Reference Range Interpretation
- Normal pancreatic function: ≥200 μg/g (specifically 200-500 μg/g range) 1
- Mild to moderate pancreatic insufficiency: 100-200 μg/g (indeterminate zone) 1
- Severe pancreatic insufficiency: <100 μg/g 1
The British Society of Gastroenterology and American Gastroenterological Association both establish 200 μg/g as the critical threshold separating normal function from pancreatic insufficiency. 1
Optimal Testing Conditions
The test must be performed on semi-solid or solid stool specimens to avoid false-positive results (falsely low values due to dilution in liquid stools). 1 This is a critical pitfall—watery diarrhea can artificially lower elastase levels even when pancreatic function is normal. 1
Test Characteristics and Stability
- Sample stability: Elastase-1 remains stable in stool for up to one week at room temperature, making it highly practical for clinical use 1, 2
- Sample requirement: Only a single 100 mg stool sample is needed 1
- Unaffected by: Simultaneous pancreatic enzyme replacement therapy or dietary intake 1, 3
- Day-to-day variation: Individual variation averages 15-26%, so borderline values (175-225 μg/g) may warrant repeat testing on different days 4, 2
Clinical Performance
The fecal elastase-1 test demonstrates:
- Sensitivity: 73-100% for moderate to severe pancreatic insufficiency 1
- Specificity: 80-100% when properly interpreted 1
- Limitation: Poor sensitivity (<60%) for mild pancreatic insufficiency, making it unreliable for early disease detection 1
This test has replaced older methods like fecal chymotrypsin due to superior stability and sensitivity. 1, 5
Extremely Elevated Values
Levels >800 μg/g definitively exclude exocrine pancreatic insufficiency and indicate robust pancreatic enzyme production, even accounting for potential dilution effects in liquid stool. 6 At this level, alternative diagnoses for gastrointestinal symptoms should be pursued (celiac disease, small intestinal bacterial overgrowth, inflammatory bowel disease, bile acid diarrhea). 1, 6