The main diseases that cause an increased excretion of faecal calprotectin are
inflammatory bowel diseases (IBD),
coeliac disease,
infectious colitis,
necrotizing enterocolitis in infants, intestinal
cystic fibrosis and
colorectal cancer. Faecal calprotectin is regularly used as indicator for IBD during treatment and as a diagnostic marker. Since calprotectin comprises as much as 60% of the soluble protein content of the cytosol of neutrophils, it can serve as a marker for the level of intestinal inflammation. Measurement of faecal calprotectin has been shown to be strongly correlated with 111-
indium-labelled
leucocytes – considered the gold standard measurement of
intestinal inflammation. Levels of faecal calprotectin are usually normal in patients with
irritable bowel syndrome (IBS). In untreated coeliac disease, concentration levels of faecal calprotectin correlate with the degree of
intestinal mucosal lesion and normalize with a
gluten-free diet. Faecal calprotectin is measured using
immunochemical techniques such as
ELISA or
immunochromatographic assays. The
antibodies used in these assays target specific
epitopes of the calprotectin molecule. == False-positive measurements ==