Fecal pancreatic elastase 1 (PE-1) is measured as a concentration in stool, so looser, watery, and diarrheal stools will almost invariably result in low elastase values due to dilution. For this reason, the Gut Zoomer specimen collection instructions recommend sampling both formed and looser parts of stool.
Thus, stool sample collections on different dates, different times in the same day, or even different sampled parts from the same stool specimen and put into the aliquot/tube, may result in different PE-1 concentrations and different measured results.
In example, collecting samples from Bristol Stool Types 5, 6, and 7 (see below images) will result in different PE-1 levels depending upon whether both more formed particulate matter or more water was added to the aliquot/tube.
Additionally, specimen stability and whether the stool was refrigerated will also affect PE-1 levels.
Last, but not least, different testing methodologies between laboratories, and different reference ranges may also account for differences in results.
For more information, see: Diagnostic Performance of Measurement of Fecal Elastase-1 in Detection of Exocrine Pancreatic Insufficiency – Systematic Review and Meta-analysis
