Diagnosis Make an Appointment Refer a Patient Ask a Question Early detection of colon polyps is important since most colon cancer develops slowly from colon polyps. The first step in diagnosing colon polyps and colon cancer is a good evaluation. This may include: Detailed medical history and physical exam. Colonoscopy: The colonoscopy is the gold standard for early detection and treatment of colon polyps. Your healthcare provider may do a colonoscopy to visualize the inside of your entire colon, not just the lower portion. Your doctor may also do a biopsy and remove any polyps found inside your colon. During a biopsy, a small amount of the tissue is taken from the lining of the colon. The polyps and tissue can be studied closely to help determine your diagnosis and the best treatment. Stool sample for occult blood: Your healthcare provider may ask you to test a stool sample for hidden (occult) blood. There may be small amounts of blood which aren't detected visually, so this test can be useful. You will be given a kit to test the stool at home. Your healthcare provider will give you instructions for collecting a small stool smear on the test kit. You will also be instructed on returning the kit. The kit can be tested to determine if it contains blood. If the test is positive, your healthcare provider may recommend a colonoscopy. Sigmoidoscopy: Your healthcare provider may do a sigmoidoscopy to visualize the inside of your colon. A small flexible tube is used to see inside the rectum and lower portion of the colon. If the test is positive, your healthcare provider may recommend a colonoscopy. Virtual colonoscopy: Currently, this is not routinely recommended for screening since the utility and risks have not been well established. Risk Factors and Symptoms Clinical Trials For more than 100 years, National Jewish Health has been committed to finding new treatments and cures for diseases. Search our clinical trials.