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. He or she will use a combination of tests. To help confirm a diagnosis of IBD, you may have one or more of the following tests and procedures:

Blood tests

  • Tests for anemia or infection. Your doctor may suggest blood tests to check for anemia — a condition in which there aren't enough red blood cells to carry adequate oxygen to your tissues — or to check for signs of infection from bacteria or viruses.
  • Fecal occult blood test. You may need to provide a stool sample so that your doctor can test for hidden blood in your stool.

Endoscopic procedures

  • Colonoscopy. This test allows your doctor to view 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, which may help confirm a diagnosis. Clusters of inflammatory cells called granulomas, if present, help confirm a diagnosis of Crohn's disease.
  • Flexible sigmoidoscopy. In this procedure, your doctor uses a slender, flexible, lighted tube to examine the last section of your colon (sigmoid).
  • Upper endoscopy. In this procedure, your doctor uses a slender, flexible, lighted tube to examine the esophagus, stomach and first part of the small intestine (duodenum). While it is rare for these areas to be involved with Crohn's disease, this test may be recommended if you are having nausea and vomiting, difficulty eating or upper abdominal pain.
  • Capsule endoscopy. This test is used to help diagnose Crohn's disease. You swallow a capsule that has a camera in it. The images are transmitted to a computer you wear on your belt, after which the camera exits your body painlessly in your stool. You may still need endoscopy with biopsy to confirm a diagnosis of Crohn's disease.
  • 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 exact diagnosis is still in question.

Imaging procedures

  • X-ray. If you have severe symptoms, your doctor may use a standard X-ray of your abdominal area to rule out serious complications, such as a perforated colon.
  • Computerized tomography (CT) scan. You may have a CT scan — a special X-ray technique that provides more detail than a standard X-ray does. This test looks at the entire bowel as well as at tissues outside the bowel. CT enterography is a special CT scan that provides better images of the small bowel. This test has replaced barium X-rays in many medical centers.
  • Magnetic resonance imaging (MRI). An MRI scanner uses a magnetic field and radio waves to create detailed images of organs and tissues. MRI is particularly useful for evaluating a fistula around the anal area (pelvic MRI) or the small intestine (MR enterography). Unlike CT, there is no radiation exposure with MRI.
  • Small bowel imaging. This test looks at the part of the small bowel that can't be seen by colonoscopy. After you drink a liquid containing barium, doctors take an X-ray of your small intestine. While this technique may still be used, it has largely been replaced by CT or MRI enterography.
Sep. 27, 2014

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