Ulcerative Colitis

Diagnosis

Before diagnosing ulcerative colitis, Mayo Clinic doctors use advanced diagnostic techniques to rule out other illnesses such as Crohn's disease, diverticulitis and colorectal cancer. Your doctor is likely to use a combination of blood tests, endoscopic exams, X-rays and tissue tests to confirm the diagnosis. Over time, you may need additional tests to monitor the disease and to watch for complications and side effects of medications.

Laboratory Tests

If you have symptoms of ulcerative colitis, your doctor is likely to begin by ordering one or more noninvasive laboratory tests, including blood tests to check for anemia and infection, liver function tests to screen for liver and bile duct problems, and stool studies to rule out bacterial, viral and parasitic infections.

Endoscopy

The next step in diagnosis at Mayo Clinic is usually a visual examination of the colon itself using an endoscope, a thin, flexible tube with a lighted camera inside its tip. The camera sends magnified images of the colon lining to a television screen. A sigmoidoscopy is an endoscopic examination of the lower third of your large intestine — the sigmoid colon. A colonoscopy — a more complete test — looks at your entire colon, sometimes including the very end of the small intestine (ileum). During endoscopic procedures, the doctor usually removes one or more small tissue samples (biopsies) and sends them to a pathologist for further study. The biopsy samples can help distinguish ulcerative colitis from other bowel disorders.

Radiology Tests

Your doctor may recommend one or more radiology tests, which sometimes provide information that can't be found using other methods. These tests include conventional X-rays, X-rays of the small bowel using a contrast material, and CT scans, which produce far more detailed images than do other X-rays. In some cases, you may have leukocyte scintigraphy, a noninvasive imaging test that uses a sample of your own white cells tagged with a radioactive material to look for areas of infection and inflammation in the intestinal tract. This test can help distinguish ulcerative colitis from Crohn's disease and may also help your doctor locate abscesses and fistulas.