Calprotectin is a complex of two proteins S100A8 & S100A9, which belong to the S100 family of calcium binding proteins. They are highly expressed in resting neutrophils, keratinocytes, infiltrating tissue macrophages and on epithelial cells active in inflammatory disease. As calprotectin comprises 60% of the soluble protein in neutrophils, intestinal inflammation results in elevated concentrations being present in the stool. Faecal calprotectin correlates with the number of neutrophil granulocytes in the intestinal lumen and is thus elevated in inflammatory bowel diseases (IBD) such as Crohn's disease and ulcerative colitis, and to a smaller and variable extent in other disorders such as neoplasia and polyps.
Faecal Calprotectin measurement is a robust, non-invasive test, shown to be the most sensitive and most specific test for differentiating IBD from IBS (irritable bowel syndrome) and other functional disorders. The concentration of faecal calprotectin present in the stool also correlates with disease activity and is therefore a useful monitoring tool able to predict relapses in IBD.
Clinical Indications Faecal calprotectin is typically requested to determine the possible present of gastrointestinal inflammation; often specifically to distinguish between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) to exclude the requirement for endoscopy. Symptoms of IBD are variable but may include diarrhoea, abdominal pain, presence of blood in the stool, fever, weakness and weight loss. In known cases of IBD, monitoring of faecal calprotectin can be used to determine the presence of a flare up in disease activity and/or remission.
Reference Range <30 mg/kg Faecal calprotectin within reference range, not consistent with GI inflammation. 30 – 80 mg/kg Equivocal Result. Suggest repeat if clinical suspicion warrants or investigate further as appropriate. 80 mg/kg Faecal calprotectin raised, consistent with GI inflammation.
Sample Container A formed stool sample should be collected in a sterile 25 ml universal container (1g minimum, 10g optimal). Please include any known clinical symptoms and drug history to aid clinical interpretation of results. Samples are stable for up to 1 week if stored at 2°C – 8°C (samples may be stored for longer intervals at -20°C, however avoid freeze thaw cycles). Please send to the lab as soon as possible.
Sample Volume 10g of formed stool sample (1g minimum).