Faecal calprotectin in the diagnosis of inflammatory bowel disease

Suspicion of inflammatory bowel disease should be raised in any patient with chronic or recurrent abdominal pain and diarrhoea. However, symptoms of inflammatory bowel disease (IBD) overlap with functional gastrointestinal disorders and those patients may not need endoscopy. Currently, colonoscopy with multiple biopsies is considered the gold standard to establish the diagnosis of IBD. Unfortunately, patient selection for endoscopy based on symptoms is not reliable. The use of guidelines of appropriateness for endoscopy yields significantly more significant findings but the selection criteria suffer from low specificity. Calprotectin is a calcium binding protein of neutrophil granulocytes that correlates well with neutrophil infiltration of the intestinal mucosa when measured in faeces. In the last decade, a large body of evidence on the diagnostic value of faecal calprotectin has accumulated and measurement of calprotectin in faeces has been suggested as a surrogate marker of intestinal inflammation. Testing of faecal calprotectin has been highly useful to distinguish organic from functional intestinal disorders in patients with abdominal complaints. Additionally, faecal calprotectin has reliably identified colonic inflammation in patients with suspected IBD. The use of this inexpensive and widely available test in the evaluation and risk stratification in patients with abdominal complaints is likely to increase in the future.