Diagnostic accuracy of faecal calprotectin in patients with active perianal fistulas

Background Faecal calprotectin (FC) is a marker of mucosal inflammation. Objective The aim of this study was to determine the diagnostic accuracy of FC to (a) differentiate between perianal fistulizing Crohn's disease (pCD) and cryptoglandular perianal fistulas; and (b) detect mucosal inflammation in pCD. Methods Patients with active perianal fistulas who had FC measured and a complete ileocolonoscopy within 10 weeks were retrospectively included. Results Fifty-six patients were included (pCD, n = 37) of whom 19 pCD patients exhibited ulcers. FC was significantly higher in pCD compared to cryptoglandular fistulas (µg/g) (708.0 (207.0–1705.0) vs 32.0 (23.0–77.0), p