Diagnostic value of faecal calprotectin in unselected outpatients referred for colonoscopy: A multicenter prospective study

ObjectivesTo evaluate the role of faecal calprotectin in consecutive outpatients referred for colonoscopy.MethodsOutpatients undergoing colonoscopy at five participating institutions were eligible. Demographic and clinical data were collected. Faecal samples were tested at a single laboratory by means of a commercially available kit.ResultsWe consecutively enrolled 870 patients. Mean levels of calprotectin were significantly higher in patients with neoplastic and inflammatory disorders when compared with subjects with a normal colonoscopy or trivial endoscopic findings. Elevated calprotectin levels (>50 mg/dl) were detected in 85% of patients with colorectal cancer, and 81% of those with inflammatory conditions but also in 37% of patients with normal or trivial endoscopic findings. In patients referred for chronic diarrhoea, sensitivity and negative predictive value were 100% in detecting either any organic colonic disease. In patients referred for symptoms of “suspected functional origin” sensitivity and negative predictive value for colorectal cancer were also 100%.ConclusionsIn unselected outpatients referred for colonoscopy, a single measurement of faecal calprotectin is not sufficiently accurate to identify those with significant colorectal disease. However, a normal result can help rule out organic disease among patients with diarrhoea and those with abdominal pain and/or constipation.