How is IBS diagnosed?
Clinicians diagnose IBS by identifying typical symptoms, taking a thorough history, and doing a complete physical examination. Blood and stool tests are often part of the initial evaluation, including blood counts, measuring markers of inflammation in blood and/or stool, and testing for celiac disease in those with diarrhea. Further evaluation is indicated when there are alarm symptoms that indicate organic disease. These include blood in the stools, unexplained weight loss, diarrhea at night, or progressive abdominal pain. A family history of colon cancer or inflammatory bowel disease, onset after age 50, and abnormal laboratory tests also merit further evaluation. In some patients, colonoscopy may be indicated, particularly for anyone 50 or older, or those with a family history of colon cancer or inflammatory bowel disease.