Monoclonal antibody testing for fecal calprotectin is superior to polyclonal testing of fecal calprotectin and lactoferrin to identify organic intestinal disease in patients with abdominal discomfort

Background and aims: Fecal calprotectin and lactoferrin are sensitive markers of mucosal inflammation. We compared three different assays in their ability to identify patients with organic intestinal disease. Methods: In a post-hoc analysis of a prospective study, we examined 405 unselected patients with abdominal complaints referred for endoscopy to the University Hospital Basel, Switzerland. Calprotectin (EK-CAL, Buhlmann Laboratories, Switzerland; PhiCal, Calpro AS, Norway) and lactoferrin (IBD-Scan, Techlab, USA) were measured using enzyme-linked immunosorbent assays. The presence of a clinically significant endoscopic finding was the primary endpoint of the study. Final diagnoses were adjudicated blinded to calprotectin values. Results: The prevalence of organic intestinal disease was 35.3%. Receiver operating characteristics analysis calculated an area under the curve (AUC) for EK-CAL of 0.918, which was significantly better than for PhiCal (AUC 0.842, P<0.001) and IBD-Scan (AUC 0.830, P=0.003) to identify patients with organic intestinal disease. Overall test accuracy was 88.1% for EK-CAL, 83.7% for PhiCal, and 81.3% for IBD-Scan. Optimal cut-off value calculated for PhiCal and IBD-Scan were lower than recommended by the manufacturer. Conclusions: Monoclonal testing of calprotectin is superior to both polyclonal calprotectin testing and fecal lactoferrin in identifying symptomatic patients with organic intestinal disease. (C) 2012 Elsevier B.V. All rights reserved.