How Is UC diagnosed?
UC is diagnosed through several different tests. If a physician suspects that IBD is the cause of symptoms, testing will help determine if it is UC or CD.
Stool culture. A physician may want to rule out other causes for bloody diarrhea, such as a bacterial infection, with a stool culture. Stool must be collected into a specimen jar and brought to a laboratory for testing in a culture. If any bacteria grow in the culture, the scientists can test it to determine what it is and how best to treat it.
Blood tests. A blood test may be used to determine a white blood cell count or if anemia is present. Repeated bouts of bloody diarrhea may cause some people to become anemic. A white blood cell count gives physicians an indication that inflammation is taking place somewhere inside the body. Neither of these tests is specific in nature: an elevated white blood cell count does not tell physicians where in the body the inflammation is located and anemia could be from another cause (such as heavy menstrual bleeding). However, both tests provide clues for physicians to use when making a diagnosis.
Fecal occult blood test. Even though the blood in the stool may be visible to the naked eye, a physician may decide to include a fecal occult blood test. This test can detect bleeding from almost anywhere in the digestive tract. It can also detect blood caused by aspirin or other medications that irritate the digestive tract, so it is important to follow physician instructions before the test. The stool collection may be done at home with a kit that is used to collect samples from 3 different bowel movements. For people not experiencing diarrhea this could take up to three days; for people having diarrhea it may take only one day. The kit is returned to the physician or laboratory for testing.
Sigmoidoscopy. A sigmoidoscopy is a way for a doctor to examine the last one third of the large intestine, which includes the rectum and sigmoid colon. To clear out the colon, patients may be asked to use laxatives or an enema, or have only liquid foods on the day of the test. (In the case of severe diarrhea, the colon may already be empty enough for the physician to see clearly.) A flexible viewing tube with a lens and light source on the end, called a sigmoidoscope, is used. A biopsy may be taken during the procedure, which will be tested to help the physician determine the cause of any inflammation. This procedure may be done either in a hospital setting or in a doctor’s office and takes about 15-30 minutes. A sigmoidoscopy is uncomfortable, but it is not painful.
Colonoscopy. A colonoscopy is used to examine the inside of the colon beyond the areas a sigmoidoscopy can reach. This test uses a colonoscope, which is a flexible tube with lenses, a tiny TV camera and a light at the end. The intestine must be empty for the procedure, and physicians may prescribe one of several ways to prepare the bowel including GoLytely, Phospho-Soda, and/or a liquid diet. Biopsies may be taken during the test, which is done in a hospital outpatient setting and may take up to 1 ½ hours. During the procedure patients are normally sedated or given “twilight sleep” so that they do not feel any pain or even remember the test.
Barium enema. A barium enema (also called a lower gastrointestinal series) is a special type of X-ray that uses barium sulfate and air to outline the lining of the rectum and colon. The barium is given in an enema which is then 'held' inside the colon while X-rays are taken. Intestinal abnormalities may appear as dark silhouettes or patterns along the intestinal lining on the X-ray. Air may be pumped into the colon to help sharpen the outline of the intestinal wall. A barium enema can be performed as an outpatient procedure, and usually takes about 45 minutes. The enema might be uncomfortable, but the X-rays are painless.
