Diagnostic performance of rapid tests for detection of fecal calprotectin and lactoferrin and their ability to discriminate inflammatory from irritable bowel syndrome

Background: Ruling out somatic bowel disease, such as inflammatory bowel disease (IBD), is an important goal in the management of abdominal complaints. Endoscopy is commonly used but is invasive and expensive. Mucosal inflammation in IBD can be detected through fecal biomarkers, though the present enzyme-linked immunoabsorbent assay (ELISA) tests require laboratory facilities. We validated the diagnostic performance of two new fecal rapid tests (FRTs) for the detection of calprotectin and lactoferrin and assessed their potential to differentiate IBD from irritable bowel syndrome (IBS). Methods: The calprotectin and lactoferrin FRTs and ELISA tests were performed on the fecal samples of 114 patients referred for endoscopy, 80% of whom had IBS and 20% IBD, and validated against the endoscopic diagnosis. Results: The sensitivity and negative predictive value of the calprotectin FRT were both 100%, whereas they were 78% and 95%, respectively, for the lactoferrin FRT. The specificity and positive predictive value were slightly higher for the lactoferrin FRT. Both FRTs had similar diagnostic accuracy as the corresponding ELISA tests. Conclusions: The calprotectin and lactoferrin rapid tests are as good as the ELISA tests in detecting colonic inflammation. Given their simple use, FRTs can support the non-invasive exclusion of IBD, notably in primary care.