A. Colonic polyps can be diagnosed with a number of screening tests, including:

Colonoscopy: In a colonoscopy, the doctor examines the rectum and colon with a camera attached to a thin, flexible tube that is threaded through the anus. If a polyp is found, the doctor may remove it or take tissue samples for analysis.

Sigmoidoscopy: Sigmoidoscopy screening is similar to a colonoscopy. However, the procedure is used for examining the rectum and lower colon. Sigmoidoscopy screening cannot be used for biopsy, or taking tissue samples. If a polyp is detected, your doctor may schedule a colonoscopy to remove it.

Barium enema: In this test, a doctor injects liquid barium into the rectum and then uses a special X-ray to take colon images. The Barium causes the colon to appear white in the x-ray pictures. Since colonic polyps are dark, they can be easily identified.

CT colonography: In a CT colonography, also known as virtual colonoscopy, a CT scan is used to construct images of the colon and rectum. After the scan, a computer combines the images to produce both 2- and 3-D views of the colon and rectum. This can show images of swollen tissues, ulcers, masses, and polyps.

Stool test: This test detects blood in your stool, which can be a sign of a polyp. A doctor provides a stool test kit and instructions for collecting the stool sample. The sample is returned to your doctor’s office for analysis.