Introduction Faecal Calprotectin (FC) can be used to distinguish between irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). NICE guidelines advise a cut-off of 50 micrograms/g when differentiating between the two; however, an area of diagnostic uncertainty exists with levels between 50 mcg/g and 150 mcg/g. We reviewed our practice with this group assessing underlying pathology, identifying confounding factors and suggesting a streamlined assessment pathway to reduce unnecessary investigations
Methods Retrospective, observational study of all Intermediate FC results from September 2014–15. Data collated from biochemical requests, known IBD patients excluded. Clinical letters, pathology results and endoscopy reports interrogated to build a detailed data set
Results 82 patients had a FC between 51–150 mcg/g, 56 females, mean age of 42.4 years. Diarrhoea was predominant in 67, constipation: 9, variable bowel habit: 7 with 41 reporting pain. Red flag symptoms were identified in 17 patients. NICE and BSG guidelines recommend testing FBC, CRP, ESR/PV and tTG when assessing for IBS and IBD. Only 19% of our patients had the full complement of tests. PV was least frequently tested, seen in only 31% of patients. TTG was checked in 83%, CRP in 69% and FBC in 81%. 46 patients had endoscopic investigations. Of those, 25 had no red flag symptoms or abnormalities identified on bloods. 17 of these scopes were reported as normal. 2 found evidence of ulceration within the bowel; however, histology excluded IBD and both patients were treated as IBS. Factors contributing elevated FC include non-steroidal inflammatory drugs (NSAIDS), proton pump inhibitors (PPIs), polyps and gastrointestinal (GI) infections. Of our patients; 27 were using PPIs, 7 NSAIDS, 8 had polyps and 5 had recent or ongoing GI infections. None of the patients were found to have IBD at the time of FC requesting or to date. 50 patients were given a confirmed diagnosis of IBS
Conclusion FC can be elevated for a variety of reasons. A cut off of 150 mcg/g appears reliable for excluding IBD. Red flag symptoms and organic disease should always be considered. NICE and BSG guidelines recommend checking FBC, CRP, PV and tTG. As demonstrated here, this can be overlooked, delaying diagnosis. Confounding factors should be considered and eliminated where possible. In the absence of organic disease, with symptoms fitting criteria for IBS as defined by ROME III, invasive imaging has not been shown to aid or alter the clinical diagnosis. Patients can be referred to primary care and managed as per local guidelines. FC may be retested at 3 months. If it remains elevated, luminal investigations could then be initiated. A prospective audit is being carried out to validate this pathway
Disclosure of Interest None Declared
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