Comparison of three commercial fecal calprotectin ELISA test kits used in patients with Inflammatory Bowel Disease

Objective: Fecal calprotectin is a noninvasive marker of intestinal inflammation used to distinguish between functional and organic bowel diseases and to evaluate disease activity among patients with Inflammatory Bowel Disease (IBD). The goal of this study was to compare three different ELISA tests measuring calprotectin in their accuracy to detect IBD and to distinguish between IBD patients with active or inactive disease. Material and methods: This study includes in total 148 fecal samples, 96 from patients with a previously confirmed IBD diagnosis and 52 from healthy controls, aged from 25 to 86 and 18 to 67 years, respectively. Disease activity in the patients was established using the following clinical activity indices: the Simple Clinical Colitis Activity Index (SCCAI), the Harvey Bradshaw Index (HBI) and the Modified Pouchitis Disease Activity Index (MPDAI). Three ELISA calprotectin tests (EK-CAL, CALPRO and HK325) were performed on fecal specimens and results compared. Results: The CALPRO calprotectin ELISA test was shown to have the best specificity of 96% compared to the HK325 and the EK-CAL calprotectin ELISA tests with 28% specificity and 74% specificity, respectively. A significant correlation between clinical activity indices and fecal calprotectin was found in patients with ulcerative colitis (p < 0.05***) and in patients with an ileoanal pouch (p < 0.05), but not in patients with Crohn's disease (p = 0.11). Conclusion: The CALPRO ELISA test performed best in measuring calprotectin in feces.