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, B¨¹hlmann 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.
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.
Monoclonal testing of calprotectin is superior to both polyclonal calprotectin testing and fecal lactoferrin in identifying symptomatic patients with organic intestinal disease.