Diagnostic yield of endoscopy in patients with abdominal complaints: incremental value of faecal calprotectin on guidelines of appropriateness

Background: European Panel on the Appropriateness of Gastrointestinal Endoscopy (EPAGE) criteria have been developed to increase diagnostic yield, but their predictive value is limited. We investigated the incremental diagnostic value of faecal calprotectin to EPAGE criteria. Methods: In a post-hoc analysis of a prospective study, EPAGE criteria were applied to 298 of 575 (51.8%) patients who had undergone esophagogastroduodenoscopy (EGD), colonoscopy or both for abdominal complaints at the Division of Gastroenterology & Hepatology at the University Hospital Basel in Switzerland. Faecal calprotectin was measured in stool samples collected within 24 hours before the investigation using an enzyme-linked immunosorbent assay. Final endoscopic diagnoses were blinded to calprotectin values. Results: Of 149 EGDs and 224 colonoscopies, 17.6% and 14.7% respectively were judged inappropriate by EPAGE criteria. Appropriate or uncertain indications revealed more endoscopic findings in both EGD (46.3% vs. 23.1%, P = 0.049) and colonoscopy (23.6% vs. 6.1%, P = 0.041) than inappropriate indications. Median calprotectin levels were higher (81.5 mu g/g, interquartile range 26-175, vs. 10 mu g/g, IQR 10 22, P < 0.001) and testing was more often positive (>50 mu g/g) in patients with endoscopic findings, both in EGD (58.2% vs. 33.0%, P = 0.005) and in colonoscopy (57.3% vs. 7.4%, P < 0.001). The use of faecal calprotectin in addition to EPAGE criteria improved the risk reclassification of patients by endoscopic findings. The calculated net reclassification index was 37.8% (P = 0.002) for EGD and 110.9% (P <0.001) for colonoscopy, thus improving diagnostic yield to 56.8% and 70.2%, respectively. Conclusions: The use of faecal calprotectin in addition to EPAGE criteria improved diagnostic yield in patients with abdominal complaints.