Flexible sigmoidoscopy.

Flexible sigmoidoscopy is a procedure that allows a gastroenterologist to examine the rectum and the lower third of the colon — the sigmoid colon — using a thin, flexible scope with a camera. It is similar to colonoscopy but focused on the lower bowel rather than the entire colon.

Because it examines a smaller area, flexible sigmoidoscopy is typically shorter than a colonoscopy and often requires a more limited preparation.

What it is used for

• Evaluating rectal bleeding or blood in the stool
• Investigating lower abdominal symptoms or changes in bowel habits
• Assessing the lower colon for inflammation, such as in proctitis or inflammatory bowel disease
• Following up on specific findings in the lower bowel

How it compares to colonoscopy

The key difference is scope. A colonoscopy examines the entire colon and is the standard for colorectal cancer screening. A flexible sigmoidoscopy examines only the lower portion. For that reason, sigmoidoscopy is generally used to evaluate specific lower-bowel symptoms rather than as a complete cancer screening. If a finding during sigmoidoscopy suggests the need to examine the full colon, your physician may recommend a colonoscopy. Learn more about colonoscopy →

Preparation

Preparation for flexible sigmoidoscopy is usually more limited than for a colonoscopy, since only the lower colon needs to be cleared. Your physician's office will provide specific instructions, which may include an enema or a limited bowel preparation beforehand.

What to expect

The procedure is performed on an outpatient basis. Your physician will discuss what form of sedation or comfort measures are appropriate for you. The examination itself is typically brief. Afterward, you may experience mild bloating or gas, which passes quickly.

Your results

Your physician can often share initial findings the same day. If a biopsy was taken, those results typically follow within one to two weeks through your physician's office.