Fecal Elastase Collection: Single Random Stool Sample
A single stool sample collected at random is sufficient for fecal elastase testing—no special preparation, dietary restrictions, or multi-day collections are required. 1
Collection Method
- Collect one random stool sample in a clean, single-use container without any special timing or preparation 1
- No dietary modifications are needed before or during collection (unlike fecal fat testing which requires high-fat diet) 1
- No fasting is required (unlike older pancreatic function tests such as the Pancreolauryl test) 1
Critical Sample Requirements
Stool Consistency Matters Most
- The sample MUST be semi-solid or solid stool—this is the single most important collection requirement 1, 2
- Liquid or watery diarrhea produces falsely low results due to dilution of elastase concentration, creating false-positive results for pancreatic insufficiency 1, 2, 3
- If the patient only produces liquid stool, the test should be deferred or results interpreted with extreme caution, as values will be artificially reduced regardless of true pancreatic function 3
Sample Size and Handling
- Only 100 mg of stool is needed for the assay—a very small amount 2
- Elastase remains stable in stool for up to one week at room temperature, making transport and storage straightforward 2
- The sample should be placed in a sterile container, labeled, and transported to the laboratory 1
No Multi-Day Collections Required
While older literature suggested collecting stool over 2-3 consecutive days due to day-to-day variability (coefficient of variation 26%) 4, current guidelines clearly state that a single random stool sample is sufficient for distinguishing pancreatic-sufficient from severely pancreatic-insufficient patients 1, 5. Research demonstrates no significant diagnostic discordance between 1-day versus 2-3 day collections for identifying severe pancreatic insufficiency 5.
Common Pitfalls to Avoid
- Do not collect liquid stool: This is the most common cause of false-positive results 1, 2, 3
- Do not confuse with fecal fat testing: Unlike quantitative fecal fat (which requires 5 days of known fat intake with 3-day stool collection), elastase testing is simple and requires no dietary preparation 1
- Do not repeat testing to assess treatment response: Exogenous pancreatic enzyme replacement therapy does not alter fecal elastase results, so repeat measurements are not useful for monitoring therapy 1
When Results Are Borderline
If elastase values fall in the indeterminate zone (100-200 μg/g), consider the stool consistency at time of collection 2. Even semi-formed stool with increased water content can lower values into this range 4, 3. In such cases, repeating the test when stool is more formed may be reasonable 4.