How is ibs diagnosed?

Rome Criteria: There is no lab test or procedure to diagnose ibs, but labs, xrays, colonoscopy, endoscopy can be used to rule out other conditions that are similar to ibs. Ibs is often diagnosed when one has the signs and symptoms of the rome criteria. These are criteria that experts have set up to diagnose ibs.

Exclusion: Ibs is a diagnosis of exclusion. If there is nothing else found and your colonoscopy and x-rays are normal, then it is likely ibs.

Rome 3 criteria: Ibs used to be a diagnosis of exclusion by some, but it has a list of symptoms from ROME III criteria

IBS is nebulous. : In working up IBS, blood testing, EGD, colonoscopy, abdominal CT and ultrasound scanning are important steps to rule out other causes of the symptoms. IBS is a diagnosis of exclusion, so other identifiable conditions must be ruled out before we consider settling upon an IBS diagnosis.