A Novel Fecal Elastase Assay for the Detection of Pancreatic Exocrine Insufficiency

Background: Fecal pancreatic elastase 1 (FPE1) is an established screening test for pancreatic exocrine insufficiency (PEI), a condition that is underdiagnosed and if not treated may cause significant morbidity. The aim of this study was to compare a new FPE1 machine based CLIA kit to an ELISA assay which is considered the de facto gold standard in our laboratory for FPE1 measurement. Methods: Levels of FPE1 from the 227 stool samples were analyzed by the ScheBo ELISA kit and the CLIA Liaison XL system simultaneously with the same cutoff values for both assays. Performance of the Liaison XL system was assessed by calculating sensitivity, specificity, and accuracy. Results: The comparison between the Liaison XL system performance and the ScheBo ELISA kit as reference revealed a sensitivity, specificity, and accuracy of 86.8%, 94.3%, and 92.1%, respectively, using a cutoff of 100 µg FPE1/g stool. When the cutoff is 200 µg FPE1/g stool the sensitivity, specificity, and accuracy were 86.6%, 97.1%, and 90.7%, respectively. Furthermore, linear correlation of FPE1 levels between the two assays were found to be significant by Pearson’s correlation coefficient test (R = 0.85, p-values < 0.0001). Conclusions: The Liaison XL system showed good laboratory performance with our pre-determined cutoff values when compared to our previous assay. An important advantage of this system is its semi-automated mechanism that enables large scale analysis of FPE1. In addition to that, the Liaison XL system is ideal for both qualitative and quantitative analysis of FPE1 allowing for its application to the clinical setting.