Clinical accuracy of a new rapid assay for fecal calprotectin measurement

Background: Fecal calprotectin is an excellent biomarker for distinguishing inflammatory bowel disease from irritable bowel syndrome and for evaluation of disease activity in Crohn's disease and ulcerative colitis. The aim of this work was to evaluate the analytical performance of a new flow immune chromatography assay by comparing it to our standardized laboratory gold standard system. Methods: A total of 100 stool samples sent for routine calprotectin level measurements were analyzed by the Liaison XL system and the QuantOn Cal assay simultaneously using the same cutoff values for both assays. Performance of the QuantOn Cal assay was assessed by calculating sensitivity, specificity, and accuracy. Results: Compared with the gold standard, the sensitivity, specificity, and accuracy of the QuantOn Cal assay were 98.7%, 76.2%, and 94.0%, respectively. Furthermore, linear correlation of calprotectin levels between the two assays were found to be significant by Pearson's correlation coefficient test (r = 0.82, p-values < 0.0001). Conclusions: The QuantOn Cal assay demonstrated good performance, both qualitative and quantitative when compared to the Liaison XL system. This novel and rapid assay is well suited for measuring fecal calprotectin as a point of care or home-based assay when laboratory services are limited or not available.