Flexible Sigmoidoscopy: What Is It, Tests & Diagnosis

A gastroenterologist, or healthcare provider specializing in the gastrointestinal system, performs a flexible sigmoidoscopy to view the inside of the lower (sigmoid) part of your colon and rectum. Your healthcare provider uses a sigmoidoscope, a flexible lighted tube with a camera. The procedure helps your healthcare provider diagnose, and sometimes treat, bowel disorders and cancer.

Flexible Sigmoidoscopy

Who might need a flexible sigmoidoscopy?

Your healthcare provider may recommend a flexible sigmoidoscopy if you experience:

Abdominal pain.
Chronic diarrhea.
Rectal bleeding.
Unexplained weight loss.

Why do healthcare providers perform flexible sigmoidoscopies?

Healthcare providers use flexible sigmoidoscopies to diagnose:

Colon cancer.
Colon polyps (groups of cells in the colon that can become cancer).
Inflammatory bowel disease (IBD), namely ulcerative colitis or Crohn’s disease.
Rectal ulcers.

What’s the difference between a flexible sigmoidoscopy and a colonoscopy?

Both procedures are screening tools for colon cancer. A sigmoidoscopy is less invasive. It allows your healthcare provider to see only the lower part of the colon. With a colonoscopy, your healthcare provider can examine all of the large intestine. If the flexible sigmoidoscopy procedure reveals polyps in your lower colon, your healthcare provider can remove them. You’ll need a colonoscopy next. During a colonoscopy, your healthcare provider can remove additional polyps before they turn cancerous.

How should I prepare for a flexible sigmoidoscopy?

Your bowels (stomach and intestines) must be completely empty before this examination. Your healthcare provider might have you use an enema in the office just before the procedure, or they’ll have you do the following at home:

Stick to a clear liquid diet (water, broth) for up to 24 hours before the procedure.
Use a prescribed bowel preparation, a laxative or an enema to soften stool and empty the bowels.

Note that your own healthcare provider’s office might have different instructions for you to follow.

How is a flexible sigmoidoscopy performed?

A flexible sigmoidoscopy takes place as an outpatient procedure at your healthcare provider’s office or medical center. You can go home the same day. Because flexible sigmoidoscopy isn’t as involved as a colonoscopy, you shouldn’t need medicine that puts you to sleep (anesthesia). The procedure may feel a bit uncomfortable, but it’s usually done in less than 30 minutes.

You’ll lie on your left side on an exam table. During the procedure, your healthcare provider:

Slides a thin, lubricated sigmoidoscope through the rectum into the lower intestine.
Pumps air through the scope into the large intestine for a better view. If you have cramps, try taking a few deep breaths.
Examines the inside of the rectum and lower intestine using video images sent from the scope’s camera.
Inserts small instruments through the scope to remove tissue samples or polyps to biopsy, if needed.
Gently removes the scope.

What should I expect after a flexible sigmoidoscopy?

You may have belly pain, bloating or cramps for an hour or so after the procedure. You should feel better after you pass gas. If your provider removed polyps or tissue, you may have some light rectal bleeding. You should be able to resume activities and a normal diet after the procedure.

What are the potential risks or complications of a flexible sigmoidoscopy?

Potential complications of a flexible sigmoidoscopy are rare but include:

Colon perforation (a tear in the colon lining that may require surgery).
Delayed bleeding (up to two weeks after the procedure).

When should I get my test results?

Diagnostic results may be available immediately at your provider’s office. Often, providers send biopsy (tissue) samples to a lab. It can take up to two weeks to get biopsy results.