The doctor would assess the patient with interview and physical examination. The diagnosis of FGID can be made based on the presence of typical symptoms. In the case of IBS, the ROME III diagnostic criteria is used. It defines IBS by the presence of abdominal pain or discomfort for at least three days per month in the last three months associated with at least two of the following features:
Investigations to exclude the presence of structural abnormality may be necessary especially in the presence of “alarm features” such as age more than 45 years old, difficulty in swallowing, blood in stool, unintended weight loss, pain while sleeping at night, fever, personal or family history of gastrointestinal cancer, abnormal physical examination and failure to improve with treatment. These investigations may include blood tests, abdominal scans and endoscopy (intestinal camera tests).
In some instances, further gastrointestinal function tests which assess the movement or the amount of bacteria in your intestines may be performed to establish the underlying cause and guide treatment but it is not necessary in most cases.
