Exams and Tests

Crohn's disease is diagnosed through a medical history and physical exam, imaging tests to look at the intestines, and laboratory tests.

Crohn's disease can be difficult to diagnose. The disease may go undiagnosed for years because symptoms usually develop gradually and the same part of the intestine is not always involved. Other diseases can also have the same symptoms as Crohn's disease. But Crohn's disease tends to cause the intestine to have a cobblestone appearance, which can help doctors diagnose it. The pattern results from the repeated formation and healing of sores (ulcers) in the intestine.

Tests used to diagnose Crohn's disease include:

• Flexible sigmoidoscopy or colonoscopy, in which a lighted viewing instrument is used to look at the inside of the colon. In general, colonoscopy is the preferred test because it can be used to examine the entire colon. Sigmoidoscopy reaches only the last part of the colon.
• Abdominal X-ray, which provides a picture of possible obstruction in the abdomen.
• Upper gastrointestinal (UGI) series with small-bowel follow-through to examine all of the small intestine. In this test the doctor examines the upper and part of the middle portions of the digestive tract. After you swallow a "shake" made of a white liquid (barium) and water, continuous X-rays (fluoroscopy) are taken to track the movement of the barium through the esophagus, stomach, and the small intestine. A video monitor displays the images.
• Upper gastrointestinal endoscopy, which allows your doctor to look at the interior lining of your esophagus, stomach, and duodenum with a thin, flexible imaging instrument called an endoscope.
• Barium enema, a test that allows the doctor to examine the large intestine (colon). For a barium enema, a white liquid (barium) is inserted through the rectum into the colon. The barium outlines the inside of the colon so that it can be more clearly seen on an X-ray.
• Computed tomography (CT) scan, which uses X-rays to produce detailed pictures of structures inside the body. A CT enterography may be done. This type of CT scan looks specifically at your small intestine for signs of Crohn's disease.
• Magnetic resonance imaging (MRI), which uses a magnetic field and pulses of radio wave energy to provide pictures of organs and structures inside the body.
• Standard blood tests and urine tests, which may be used to check for anemia, inflammation, or malnutrition. Depending on the symptoms, an erythrocyte sedimentation rate (ESR, or sed rate) or C-reactive protein (CRP) blood test may be done to look for infection or inflammation.