Usefulness of fecal immunochemical test and fecal calprotectin for detection of active ulcerative colitis

Background/Aims: Ulcerative colitis undergoes periods of exacerbation and remission. Fecal calprotectin levels increase with gut inflammation and correlate with endoscopic disease activity in ulcerative colitis. Intestinal blood loss and fecal immunochemical test levels also correlate with endoscopic disease activity. This study statistically evaluated the usefulness of fecal calprotectin, fecal immunochemical test, and C-reactive protein (CRP) as markers of disease activity. Methods: A total 106 ulcerative colitis patients who underwent endoscopy and fecal calprotectin, fecal immunochemical test, and CRP testing, from March 2015 to August 2016, were retrospectively reviewed. Disease activity was assessed using a partial Mayo score and Mayo endoscopic score. The ability of fecal and serologic tests to reflect endoscopic disease severity was statistically evaluated. Results: Among 106 patients, 68 underwent endoscopy and stool study within 2 weeks. In patients with mild to severe activity, fecal immunochemical test and fecal calprotectin were superior to CRP at Mayo endoscopic score detection rate. The area under the curves of fecal immunochemical test and fecal calprotectin for the detection of Mayo endoscopic score =1 were 0.956 and 0.942, respectively, and were superior to that of CRP (0.756). At Mayo endoscopic score, the effects of combination of fecal immunochemical test and CRP or fecal calprotectin and CRP were found to be higher than those of the independent fecal immunochemical test or fecal calprotectin. Conclusions: Fecal immunochemical test and fecal calprotectin can effectively detect active ulcerative colitis better than remission. As these markers reflect the status of mucosal inflammation, they may reduce the requirement for invasive endoscopic examination.