Anoscopy, proctoscopy, and sigmoidoscopy tests allow your health professional to look at the inner lining of your anus, rectum, and the lower part of the large intestine (colon). These tests are used to look for abnormal growths (such as tumors or polyps), inflammation, bleeding, hemorrhoids, and other conditions (such as diverticulosis).

These test use different scopes look at different sections of the colon.

• Anoscopy. During an anoscopy, a short, rigid, hollow tube (anoscope) that may contain a light source is used to look at the last 2 in. of the colon (anal canal). Anoscopy can usually be done at any time because it does not require any special preparation (enemas or laxatives) to empty the colon.
• Proctoscopy. During a proctoscopy, a slightly longer instrument than the anoscope is used to view the inside of the rectum. You usually will have to use enemas or laxatives to empty the colon before the test is done.
• Sigmoidoscopy. During a sigmoidoscopy, a lighted tube that may be either rigid or flexible is inserted through the anus. Your health professional can remove small growths and collect tissue samples (biopsy) through a sigmoidoscope. You will have to use enemas or laxatives (or both) to empty the colon before the test is done.
  • The flexible sigmoidoscope is about 2.3 ft long and 0.5 in. wide with a lighted lens system. This instrument allows your health professional to see around bends in the colon. A flexible sigmoidoscope allows a more complete view of the lower colon than a rigid scope and usually makes the examination more comfortable. The flexible sigmoidoscope generally has replaced the rigid sigmoidoscope.
  • The rigid sigmoidoscope is used less often. It is about 10 in. to 12 in. long and 1 in. wide. It allows your health professional to look into the rectum and the bottom part of the colon, but it does not reach as far into the colon as the flexible sigmoidoscope.

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Why It Is Done

These tests are done to:

• Detect problems or diseases of the anus, rectum, or lower large intestine (sigmoid colon). These tests are often done to investigate symptoms such as unexplained bleeding from the rectum, long-lasting diarrhea or constipation, blood or pus in the stool, or lower abdominal pain.
• Remove polyps or hemorrhoids.
• Monitor the growth of polyps or the treatment of inflammatory bowel disease.
• Screen for colon cancer or polyps.

How To Prepare

Anoscopy

Usually, no preparation is needed for an anoscopy.

Proctoscopy and sigmoidoscopy

Test preparation for a proctoscopy and sigmoidoscopy may be similar. Before the test:

• Talk with your health professional to find out if you need to stop taking some medicines, such as warfarin, before the test.
• Talk with your health professional to find out if you need to take antibiotics before the test, especially if you have a heart murmur, an artificial heart valve, or an artificial implant (such as a replacement joint).
• Tell your health professional if you have been diagnosed with peritonitis, diverticulitis, or toxic megacolon or if you have had recent bowel surgery.