Consecutive measurements by faecal immunochemical test in quiescent ulcerative colitis patients can detect clinical relapse

Background: We have reported that results of the quantitative faecal immunochemical test (FIT; haemoglobin concentrations in faeces measured using an antibody for human haemoglobin) effectively reflect the mucosal status of ulcerative colitis (UC). The aim of this study was to evaluate the predictability of flare-up in quiescent UC patients by consecutive FIT evaluation. Methods: Patients with UC who fulfilled the following criteria by index colonoscopy were enrolled: Clinical remission; mucosal healing (Mayo endoscopic subscore 0); and negative FIT (less than 100ng/mL). These patients were followed up prospectively every 1-3 months by monitoring patient symptoms and FIT results between index and subsequent colonoscopies. Results: The intervals between 2 colonoscopies (median 2.51 years) of 83 patients (49 males, median age at onset 34 years, median disease duration 9.74 years) were analysed. None of the 43 (52%) patients who maintained negative FIT throughout the observation period exhibited clinical relapse. On the other hand, 25/40 (63%) patients who showed positive conversion of FIT during the period experienced relapse. The cutoff FIT value of 450ng/mL could predict relapse with 73% positive predictive value and 96% negative predictive value. Moreover, positive conversion of FIT preceded occurrence of symptoms by 1 month or more in nearly one-third of patients with relapse. Conclusions: Consecutive measurements of FIT in quiescent UC patients who achieved mucosal healing with negative FIT would help identify patients with clinical relapse whose symptoms had not yet presented. Further investigations are required for more precise prediction of relapse with this modality.