Fecal Calprotectin and Organic Gastrointestinal Disease: A Systematic Review

This review aimed to assess the diagnostic utility of fecal calprotectin (FCP) for identifying organic gastrointestinal disease (OGID) in patients undergoing colonoscopy for gastrointestinal discomfort or active progression of inflammatory bowel disease (IBD). Studies published between January 2013 and December 2022 evaluating the clinical efficacy of FCP for differentiating OGID against functional gastrointestinal disease (FGID) were identified using PubMed, Cochrane, and Scopus databases. Clinical diagnostic studies involving individuals with lower gastrointestinal symptoms; using FCP as a diagnostic biomarker either in primary, secondary, or tertiary healthcare centers conducted either prospectively or retrospectively using stool samples (index test), contrasting FCP with a reference test, such as colonoscopy, or endoscopy, and assessed using enzyme-linked immunosorbent assay were reviewed. The included studies were subjected to the revised Quality Assessment of Diagnostic Accuracy Studies for assessing the methodological quality by two independent authors. An initial literature search yielded 545 articles rendering 417 records after removing the duplicate records. After reading the abstracts and titles, 89 articles were eligible for full-text screening. The qualitative synthesis resulted in 20 articles. The efficient use of FCP for differentiating IBD from irritable bowel syndrome was investigated in 15 studies.Two of the included studies assessed the diagnostic ability of FCP to distinguish OGID from FGID, two studies utilized patients with ulcerative colitis, and one study involved patients with Crohn's disease. Overall study quality was high for 65% of studies,moderate for 25% of studies, and low for 10% of studies. The review outlined the diagnostic accuracy of non-invasive FCP assessment for OGID in various clinical scenarios and in individuals of various ages. FCP is used as a tool for screening and monitoring in clinical practice for determining the need of further comprehensive investigations, thereby reducing the redundant use of invasive techniques.