To confirm a diagnosis of ulcerative colitis, most patients have either flexible sigmoidoscopy or colonoscopy. Both procedures use a small camera and light to view the insides of your large intestine.
A biopsy may be done during either procedure. In a biopsy, small samples of tissue are clipped from the lining of the intestine. They may be examined for signs of inflammation.
Many temporary conditions, such as infections, cause the same symptoms as ulcerative colitis. Therefore, your doctor will want to test your stool for other conditions such as bacterial infections or parasite infections.
Blood tests may also be done to check for a low blood count or low iron levels. These can occur in ulcerative colitis.
Blood tests may be done to detect inflammation, and to check on your liver. Inflammation of the liver ducts occurs in some people with ulcerative colitis.