Usefulness of stool hemoglobin and fecal calprotectin for detecting of mild to moderate ulcerative colitis

Background: Ulcerative colitis (UC) is a major type of IBD with periods of waxing and waning. Intestinal blood loss is an major symptom in UC and stool Hb level correlated well with the endoscopic disease activity of UC patients. Fecal calprotectin (FC) level increases at gut inflammation and correlate well with endoscopic disease activity in UC. We evaluated the usefulness of FC, quantitative stool Hb (SHb), and CRP as a marker for reflecting UC disease activity Methods: A total 106 UC patients who performed FC, SHb, CRP, and endoscopy at Korea University Hospital through March 2015 to August 2016 were retrospectively reviewed. UC disease severity was assessed using partial Mayo score (remission=0–1, mild=2–4, moderate=5–6, severe=7–9) and Mayo endoscopic score (remission=0, mild=1, moderate=2, severe=3). The ability of tests for reflecting disease severity was compared using Receiver Operator Characteristic–Area under the Curve (ROC-AUC) statistic. Results: Among 106 patients, 26 patients have moderate to severe activity based on partial Mayo score. The area under the curve (AUC) in ROC analysis of SHb and FC to predict partial Mayo score more than 1 were 0.717 and 0.727 (AUC of CRP, 0.549). There was no significant difference between SHb and FC (PSHb vs CRP: 0.007, PFC vs CRP: 0.006, PSHb vs FC: 0.864). For detecting Mayo endoscopic score 1 or more, the AUC of SHb and FC were 0.956, 0.942 (AUC of CRP, 0.756, p<0.05). Conclusions: SHb and FC can effectively and noninvasively detect mild to moderate UC. Considering that SHb and FC reflects the status of mucosal inflammation and disease activity well, they might reduce the requirement for invasive endoscopic examinations.