Tests and diagnosis

By Mayo Clinic Staff

Your doctor will likely diagnose inflammatory bowel disease only after ruling out other possible causes for your signs and symptoms, including ischemic colitis, infection, irritable bowel syndrome (IBS), diverticulitis and colon cancer. To help confirm a diagnosis of IBD, you may have one or more of the following tests and procedures:

  • Blood tests. Your doctor may suggest blood tests to check for anemia or infection. Tests that look for the presence of certain antibodies can sometimes help diagnose which type of inflammatory bowel disease you have, but these tests can't definitely make the diagnosis.
  • Stool sample. The presence of white blood cells in your stool indicates an inflammatory disease, possibly IBD. A stool sample can also help rule out other disorders, such as those caused by bacteria, viruses and parasites. Your doctor can also check for a bowel infection, which is more likely to occur in people with IBD.
  • Colonoscopy. This exam allows your doctor to view the inside of your entire colon using a thin, flexible, lighted tube with an attached camera. During the procedure, your doctor can also take small samples of tissue (biopsy) for laboratory analysis. Sometimes a tissue sample can help confirm a diagnosis.
  • Flexible sigmoidoscopy. In this procedure, your doctor uses a slender, flexible, lighted tube to examine the last portion of your colon (sigmoid colon). The test may miss problems higher up in your colon, and it doesn't give a full picture of how much of the colon has been affected. But if your colon is severely inflamed, your doctor may perform this test instead of a full colonoscopy.
  • Barium enema. This diagnostic test allows your doctor to evaluate your entire large intestine with an X-ray. Barium, a contrast solution, is placed into your bowel using an enema. Sometimes, air is added as well. The barium coats the bowel lining, creating a silhouette image of your rectum, colon and a portion of your small intestine. This test is rarely used anymore, and it can be dangerous because the pressure required to inflate and coat the colon can lead to rupture of the colon.
  • X-ray. A standard X-ray of your abdominal area may be done to rule out toxic megacolon or a perforation of the colon if these conditions are suspected because of severe symptoms.
  • Computerized tomography (CT) scan. A CT scan of your abdomen or pelvis may be performed if your doctor suspects a complication from ulcerative colitis or inflammation of the small intestine that might suggest Crohn's disease. A CT scan may also reveal how much of the colon is inflamed.
  • Magnetic resonance imaging (MRI). An MRI scanner uses a magnetic field and radio waves to create detailed images of organs and tissues. Most MRI machines are large, tube-shaped magnets. During the test, you lie on a movable table inside the MRI machine. This test is very helpful in diagnosing and managing Crohn's disease. It's biggest advantage is that there is no radiation exposure. It's particularly useful for evaluating a fistula around the anal area (pelvic MRI) or the small intestine (MRI enterography).
  • Capsule endoscopy. If you have signs and symptoms that suggest Crohn's disease but other diagnostic tests are negative, your doctor may perform capsule endoscopy. For this test you swallow a capsule that has a tiny camera in it. The camera takes pictures as it moves through your digestive tract, and the images are transmitted to a computer that you wear on your belt. Your doctor later downloads the images, which are then displayed on a monitor and checked for signs of Crohn's disease. Once it's made the trip through your digestive system, the camera exits your body painlessly in your stool.
  • Double-balloon endoscopy. For this test, a longer scope is used to look further into the small bowel where standard endoscopes don't reach. This technique is useful when capsule endoscopy shows abnormalities but the diagnosis is still in question. It allows for biopsy of the abnormal area. It's usually performed in specialized endoscopy centers.
  • Small bowel imaging. This test looks at the part of the small bowel that can't be seen by colonoscopy. You drink a solution containing barium, then X-ray, CT or MRI images are taken of your small intestine. The test can help locate areas of narrowing or inflammation in the small bowel that are seen in Crohn's disease. The test can also help your doctor determine which type of inflammatory bowel disease you have.
Dec. 13, 2012

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