Introduction Calprotectin is a protein released by neutrophils in response to the presence of inflammation in the bowel 1. Based on secondary care data with a cut-off of 50 mcg using ELISA assay it has a sensitivity of 93% and specificity of 94% 2 to exclude inflammatory bowel disease (IBD) from functional bowel disorders. Calprotectin can be measured in a stool sample with this non-invasive test significantly cheaper than endoscopy and associated new patient referral 3,4. Faecal calprotectin (FC) has also been shown to correlate with mucosal disease activity and can help to predict response to treatment or relapse in IBD 1. We report the routine use of FC in gastroenterology practice at our hospital.
Methods All FC tests performed between 01/07/12 and 31/12/12 were systematically collected and reason for testing determined. Endoscopic, histological, radiological, laboratory and clinical records were systematically searched to identify tests performed in patients with FC results.
Results 294 FC tests were performed during the study period: 203 (69.0%) for assessment of IBD and 91 (31.0%) tests to exclude IBD in patients with suspected functional bowel disorders. Mean age of patients with suspected functional bowel disorders was 45 (SD 16.8) years and 62.6% were female. Of the patients with suspected IBS who had a normal FC value (n = 75), 50.7% had a colonoscopy, 20.0% had CT or MRI and 9.3% had a flexible sigmoidoscopy. Of the 75 patients with suspected functional bowel disorder with normal FC values, 2 patients were diagnosed with Crohn’s disease affecting the terminal ileum on colonoscopy. For patients with suspected IBS the test had a specificity of 80.2% and a negative predictive value of 97.3%.
Conclusion Despite normal FC result, a significant proportion of young adults with suspected functional bowel disorder undergo colonoscopy with normal test results. As other studies have shown, consideration of the FC result before further investigations are ordered can reduce the number of patients requiring endoscopy or imaging and thus reduce cost 1. However, FC is less sensitive for small bowel Crohn’s disease and therefore careful history taking is required to ensure this is not missed due to a negative FC result.
Smith LA et al. World J Gastroenterol 2012 Dec 14; 18(46):6782–6789
Nice Guideline DG11 Faecal calprotectin diagnostic tests for inflammatory diseases of the bowel
NHS England National Tariff Payment System. http://www.monitor.gov.uk/NT. Accessed on 22/1/14
Faecal Calprotectin - Is it Requested Appropriately and is it Cost Effective? Gut2013;62:A266-A267
Disclosure of Interest None Declared.