Diagnosis

Diagnosis

The doctor will take your medical history and perform a thorough physical examination. The disease is particularly difficult to diagnose in children, in whom IBD may be mistaken for an infection or even depression if other characteristic symptoms, such as bloody diarrhea and weight loss, are not present. Slow growth may be a key feature in making a diagnosis, particularly of Crohn's disease, in children.

Several laboratory tests may be taken, such as the following:

• Blood tests are used for various purposes. An increased number of white blood cells may indicate the presence of inflammation. Blood tests are used to determine the presence of anemia and to measure liver enzymes. (They are abnormal in about 3% of ulcerative colitis cases.) New blood tests that measure certain antibodies may make it easier to differentiate Crohn's disease from ulcerative colitis in children.
• A stool sample is taken and examined for blood, infectious organisms, or both.

Imaging Procedures Used for Diagnosis

Endoscopic Procedures. Flexible sigmoidoscopy and colonoscopy are endoscopic procedures. They are important in the diagnosis of both ulcerative colitis and Crohn's disease. Both procedures involve snaking a fiberoptic tube called an endoscope through the rectum to view the lining of the colon. The doctor may also insert instruments through the endoscope to remove a tissue sample for a biopsy.

• Sigmoidoscopy, which is used to examine the rectum and left (sigmoid) colon, lasts about 10 minutes and is done without sedation. It may be mildly uncomfortable, but it is not painful. Ulcerative colitis almost always involves the lower left colon and rectum and is diagnosed using sigmoidoscopy. The doctor usually observes an evenly distributed inflamed surface lining the intestine, and the bowel wall bleeds easily when touched with a swab.
• Colonoscopy allows a view of the entire colon and requires a sedative, but it is still performed on an outpatient basis. It is helpful for distinguishing between Crohn's disease and ulcerative colitis and in screening for colon cancer.