Fecal immunochemical test as a biomarker for inflammatory bowel diseases: can it rival fecal calprotectin?

Accurate evaluation of disease activity is essential for choosing an appropriate treatment and follow-up plan for patients with inflammatory bowel disease (IBD). Endoscopy is required for accurately evaluating disease activity, but the procedures are sometimes invasive and burdensome to patients. Therefore, alternative non-invasive methods for evaluating or predicting disease activity including mucosal status are desirable. Fecal calprotectin (Fcal) is the most widely used fecal marker for IBD, and many articles have described the performance of the marker in predicting disease activity, mucosal healing (MH), treatment efficacy, and risk of relapse. Fecal immunochemical test (FIT) can quantify the concentration of hemoglobin in stool and was originally used for the screening of colorectal cancer. We recently reported that FIT is also a useful biomarker for IBD. A direct comparison between the use of Fcal and FIT showed that both methods predicted MH in ulcerative colitis equally well. However, in the case of Crohn's disease, FIT was less sensitive to lesions in the small intestine, compared to Fcal. FIT holds several advantages over Fcal in regards to user-friendliness, including a lower cost, easy and clean handling, and the ability to make rapid measurements by using an automated measurement system. However, there is insufficient data to support the application of FIT in IBD. Further studies into the use of FIT for evaluating the inflammatory status of IBD are warranted.