[Diagnosis of irritable bowel syndrome: a systematic review]

Irritable bowel syndrome(IBS) is a very common functional gastrointestinal disorder characterized by abdominal discomfort, bloating, and disturbed defecation. Patients with IBS have a tendency to visit physicians more frequently than those without IBS, thus annual economic consequences of IBS in the Western countries are substantial. Therefore, guidelines for the diagnosis and treatment of IBS patients have been designed to give a favored effect on the Department of Gastroenterology's overall performance. A variety of criteria have been developed to identify a combination of symptoms to diagnose IBS, including Manning and Rome I, II, and III criteria. Overall, Manning's criteria had a pooled sensitivity and specificity, 78% and 72%, respectively. In addition, the Rome I criteria had a sensitivity and specificity, 71% and 85%, respectively. However, none described the accuracy of Rome II and III yet. Alarm features such as rectal bleeding and nocturnal pain offer little discriminative value in separating patients with IBS from those with organic diseases. Even though anemia and weight loss have poor sensitivity for organic diseases, they offer very good specificity. Since specific biomarker of IBS is not yet available, diagnostic tests are frequently performed to exclude organic diseases. However, the accuracy of diagnostic tests is disappointing. CBC, chemistry, thyroid function test, stool exam, ultrasonography, hydrogen breath test, erythrocyte sedimentation rate, and C-reactive protein have all very limited accuracy in discriminating IBS from organic diseases. This systemic review is targeted to establish the strategy of IBS treatment, which is very necessary for the current clinical practice.