When to conduct testing in patients with suspected irritable bowel syndrome.

Patients who have abdominal discomfort or pain plus disturbed defecation warrant a careful history taking and physical examination. The presence of positive symptom criteria for irritable bowel syndrome (IBS) usually correctly identifies the underlying IBS diagnosis. The clinical evaluation may uncover findings that cause concern about underlying organic disease ("alarm features" or "red flags"). Traditional alarm features include bleeding, obvious anemia, weight loss, and older age at onset. Although the diagnostic utility of most of these red flags has not been tested, patients with these symptoms should be investigated promptly. In the primary care setting, most patients who have alarm symptoms will have a negative further evaluation, and the original IBS diagnosis will be confirmed. In the past, numerous tests (eg, complete blood cell count, flexible sigmoidoscopy) were considered routine for patients with suspected IBS in the primary care setting. However, available data do not support this approach; these patients do not have an increased likelihood of most organic diseases compared with control populations without IBS. Although celiac disease may occur more frequently in persons with IBS, the yield of serologic testing is likely to be low. Testing is generally not required in patients with positive symptom criteria for IBS and an absence of alarm features.