Introduction A positive diagnosis of irritable bowel syndrome (IBS), without the need for recourse to investigation, is encouraged. Patients meeting symptom-based diagnostic criteria for IBS are often given reassurance that there is no serious underlying pathology, and treated symptomatically. However, some studies have suggested that an organic diagnosis, such as coeliac disease or pancreatic insufficiency, may be missed if this approach is adopted. We aimed to examine the yield of investigation in patients meeting criteria for IBS in real-life clinical practise.

Methods Review of consecutive unselected new patient referrals to a single Gastroenterologist’s outpatient clinic during a 2-year period, from January 2010 to December 2011. All clinic letters were reviewed retrospectively, and symptoms reported by the patient at the initial consultation were recorded. Those who described lower abdominal pain associated with a change in bowel habit, in the absence of alarm features such as rectal bleeding or weight loss, were classified as meeting criteria for IBS at presentation. IBS subtype was classified as diarrhoea-predominant (IBS-D), constipation-predominant (IBS-C), or mixed (IBS-M), according to stool pattern. Radiology, endoscopy, chemical pathology, and histopathology databases were then cross-examined in order to ascertain the final diagnosis following full investigation, to the level deemed appropriate by the consulting physician.

Results There were 397 consecutive unselected new patient referrals to a single Gastroenterologist between January 2010 and December 2011. Of these, 38 (9.6%) (mean age 40.6 years, 23 (60.5%) female) reported symptoms compatible with IBS in the absence of alarm features, of whom 23 (60.5%) met criteria for IBS-D, 9 (23.7%) IBS-C, and 6 (15.8%) IBS-M. In total, 7 (18.4%) patients were found to have an organic explanation for their symptoms after investigation. The commonest organic diagnosis among patients meeting criteria for IBS was bile acid malabsorption, occurring in 4 (10.5%). Other organic diagnoses detected included inflammatory bowel disease-unclassified (1 patient), pancreatic insufficiency (1 patient), and coeliac disease (1 patient). Organic diagnoses were commoner among those meeting criteria for IBS-D, occurring in 6 (26.1%) patients.

Conclusion Our data suggest that organic diagnoses may occur in up to one in five patients meeting criteria for IBS without alarm features. Bile acid malabsorption occurred in more than 10%. The yield of investigations in IBS-C was low, suggesting these individuals can be labelled confidently as having IBS without the need for further investigation.

Disclosure of Interest None Declared.