Your doctor will take several steps in order to accurately diagnose ulcerative colitis (UC). These steps will also help rule out other possible causes of your symptoms, such as a bacterial or viral infection, and make sure you don't have another gastrointestinal problem like irritable bowel syndrome or Crohn's disease. To do this, your doctor will look at your medical history, perform a thorough physical exam, and perform several tests. Below are descriptions of some tests your doctor may perform.
- Stool examination: Infections of the colon can sometimes mimic ulcerative colitis. Analyzing a stool sample can help your gastroenterologist eliminate possible bacterial, viral, or parasitic causes of your diarrhea. Your doctor may also check the stool sample for blood, which could mean the intestine is bleeding.
- Blood tests: Your gastroenterologist will perform blood tests to look for several things. Blood tests can check for anemia, which may indicate bleeding in the colon or rectum. Your gastroenterologist may also order blood tests to look at your white blood cell count and other markers, which would indicate an infection or inflammation.
- Colonoscopy or sigmoidoscopy: These tests may be performed to confirm the diagnosis of ulcerative colitis or to determine the extent of the inflammation inside the intestine. During either test, the gastroenterologist inserts a long, flexible, lighted tube with a camera at the end called an endoscope into the anus to see the inside of the colon and rectum. The tube is connected to a computer and TV monitor. The test allows the gastroenterologist to see any inflammation, bleeding, or ulcers on the colon wall. The gastroenterologist may also take a sample of tissue from the lining of the colon to examine with a microscope.
- Barium enema x-ray: During this procedure, an enema is used to fill the colon with barium, a chalky white solution. The barium will show up white on the x-ray, allowing your doctor a detailed view of the colon, including any ulcers or other abnormalities.