Introduction The diagnosis of irritable bowel syndrome (IBS) requires careful exclusion of ‘red flag’ clinical features and blood abnormalities which may indicate an alternative organic diagnosis such as inflammatory bowel disease (IBD).¹ The chronic, recurrent nature of the symptoms of IBS may lead to diagnostic anxiety. Faecal calprotectin (FC) is a useful non-invasive test for intestinal inflammation that can distinguish IBS from IBD when specialist referral or further investigations are being considered.² Confident use of FC is likely to save costs by reducing referral and endoscopy burden.

Methods This retrospective, observational study investigated the management of patients diagnosed with IBS following gastroenterologist review who had negative FC (<50 µg/g faeces) tested between September 2014 and September 2015. Electronic records were interrogated for clinical letters and the results of blood (full blood count, C-reactive peptide, erythrocyte sedimentation rate/plasma viscosity and coeliac serology), stool and endoscopic investigations. Red flag indicators were defined as per NICE clinical guideline 61.¹ The cost-saving implications of negative FC testing to confirm IBS were evaluated using estimated per person costs of an ELISA test and POCT CalDetect (£22.79), outpatient gastroenterology appointment (£164.00), colonoscopy (£577.68) and flexible-sigmoidoscopy (£351.00).^2,3

Results During the study period 173 non-IBD patients (age range: 17–81 y, median: 35 y, 72% female) were referred for gastroenterologist review and had a negative FC test. There were no documented red flag clinical features nor significant abnormalities on blood testing in 30 patients diagnosed with IBS. 23% and 17% of these patients had undergone colonoscopy and flexible sigmoidoscopy respectively. No significant abnormalities were detected. The estimated cost-saving impact of a negative FC to confirm a diagnosis of IBS and limit unnecessary referral and endoscopy was £357.29 per person.

Conclusion A negative FC may provide cost-effective diagnostic reassurance in patient with suspected IBS without red flag clinical features or blood abnormalities in whom specialist referral or endoscopy is considered. There is a need for FC testing to be made available to primary care physicians with robust pathways to support decision-making.

References 1 NICE clinical guideline 61 [CG61]. Published February 2008.

2 Faecal calprotectin diagnostic tests for inflammatory diseases of the bowel. NICE diagnostics guidance [DG11]. Published October 2013.

3 Suspected cancer: recognition and management of suspected cancer in children, young people and adults. Clinical guideline appendices A-E. Published June 2015. Commissioned by NICE.

Disclosure of Interest None Declared