Fecal calprotectin: beyond intestinal organic diseases

Fecal calprotectin (FC) is a calcium-binding protein with antimicrobic, imunomodulatory and antiproliferative properties that is mainly found in the cytoplasm of neutrophil granulocytes. During the last decades, FC became an increasingly useful tool both for gastroenterologists and for general practitioners for distinguishing inflammatory bowel disease (IBD) from irritable bowel syndrome. FC correlates with clinical scoring systems and endoscopic lesions in IBD and is considered a reliable biomarker for the prediction of clinical relapse or remission. However, FC elevation could be observed also in other gastrointestinal pathological conditions including infective colitis, microscopic colitis, eosinophilic colitis, adenomas and colorectal cancer. In addition, there are several non-pathological conditions that can lead to altered FC values. In this review, we aimed to point out individual, environmental and method-related factors that can affect FC measurement and thus its clinical interpretation.