Systematic review: accuracy of symptom-based criteria for diagnosis of irritable bowel syndrome in primary care

Background  Despite the trend towards making a positive diagnosis of irritable bowel syndrome (IBS), many health care providers approach IBS as a diagnosis of exclusion.
Aim  To summarize available evidence on the diagnostic performance of symptom-based IBS criteria in excluding organic diseases, and of individual signs and symptoms in diagnosing IBS and to additionally assess the influence of sources of heterogeneity on diagnostic performance.
Methods  We searched PubMed and EMBASE and screened references. Studies were selected if the design was a primary diagnostic study; the patients were adults consulting because of non-acute abdominal symptoms; the diagnostic test included an externally validated set of IBS criteria, signs, or symptoms. Data extraction and quality assessment were performed by two reviewers independently. The review adhered to the most recent guidelines as described in the Cochrane Diagnostic Reviewers' Handbook.
Results  A total of 25 primary diagnostic studies were included in the review. The performance of symptom-based criteria in the exclusion of organic disease was highly variable. Patients fulfilling IBS criteria had, however, a lower risk of organic diseases than those not fulfilling the criteria.
Conclusions  With none of the criteria showing sufficiently homogeneous and favourable results, organic disease cannot be accurately excluded by symptom-based IBS criteria alone. However, the low pre-test probability of organic disease especially among patients who meet symptom-based criteria in primary care argues against exhaustive diagnostic evaluation. We advise validation of the new Rome III criteria in primary care populations.