Evaluation of mucosal healing of ulcerative colitis by a quantitative fecal immunochemical test

Accumulating evidence has underlined the importance of mucosal healing as a treatment goal for ulcerative colitis (UC). Quantitative fecal immunochemical tests (FITs), which can rapidly quantify fecal blood with automated equipment, have been used recently to screen for colorectal neoplasia. The aim of this study is to determine whether an FIT can evaluate mucosal healing in UC.

Feces collected from UC patients who underwent colonoscopy were examined by FITs, and results were compared with colonoscopic findings. Mucosal status was assessed using the Mayo endoscopic subscore classification. Maximum score for the colorectum in each patient was recorded.

Evaluated were FIT results in conjunction with 310 colonoscopies that were performed in 152 UC patients. A large majority of patients with a Mayo 0 endoscopic score had negative FIT (<100 ng/ml) results (92%), and the proportion of negative FIT results decreased with increases in the Mayo score (Mayo 1: 47%, Mayo 2: 13%, Mayo 3: 12%, P<0.0001, Cochran-Armitage trend test). When the negative FIT was defined as <100 ng/ml, the sensitivity and specificity of a negative FIT for mucosal healing (Mayo 0) were 0.92 and 0.71, respectively. When mucosal healing was defined as Mayo 0 or 1, those were 0.60 and 0.87, respectively. In addition, a positive FIT (≥100 ng/ml) predicted mucosal inflammation (Mayo 2 or 3) with sensitivity 0.87 and specificity 0.60, respectively.

The FIT can effectively and noninvasively evaluate mucosal healing in UC. This easy, rapid method can help evaluate and control disease activity of UC.