Home Health A-Z Flexible Sigmoidoscopy

Flexible Sigmoidoscopy

Verified By Apollo Doctors July 11, 2021 3378 0
Flexible sigmoidoscopy
Flexible sigmoidoscopy

What is flexible sigmoidoscopy?

Flexible sigmoidoscopy is a test to screen the lower colon and inner lining of your rectum. A thin, flexible tube with light known as a sigmoidoscope is inserted into the rectum through the anus. The tube has a small video camera attached to it that allows the doctor to see inside of the intestinal walls and check for symptoms of ulcers, abnormal cells, polyps, and cancer. 

Why is flexible sigmoidoscopy performed?

A gastroenterologist may recommend this test to diagnose bowel problems, such as abdominal pain, changes in bowel habits, rectal bleeding, chronic diarrhea, inflammatory bowel disease, or other intestinal problems. The test can also expose polyps that can eventually turn into colon cancer

What are the risks associated with flexible sigmoidoscopy?

You may experience cramps or feel gas forming in the abdomen. But these symptoms will pass. Although risks associated with a flexible sigmoidoscopy are rare, contact your doctor immediately if you observe the following symptoms:

The test might have to be redone if the doctor could not get a clear image of the colon and rectum.

Call 1860-500-1066 to book an appointment.

What are the preparations needed for a flexible sigmoidoscopy?

Before a flexible sigmoidoscopy test, your colon should be empty to avoid any obstruction while viewing the colon. Your doctor may give you some instructions to follow before the test, such as:

  • Laxative Medications: Your doctor might give you a laxative in a pill or liquid form to take the night before the exam to soften stool and empty your bowels. A few hours before the test, you will be given enemas to empty your colon.
  • Medical Conditions: Inform your doctor if you have any medical conditions, including heart or lung problems, allergy to medications, diabetes, or pregnancy. Also, let the doctor know if you take blood thinners, aspirin, or supplements that contain iron. The doctor might recommend a dosage adjustment or ask you to stop taking these medications temporarily.

What to expect from a flexible sigmoidoscopy test?

A flexible sigmoidoscopy is an outpatient test generally conducted at a medical clinic or hospital. It is completed in less than 30 minutes. The test does not require the administration of anesthesia. During the test, you will have to lie on your left and pull your knees towards your abdomen. The doctor will then insert a thin, lubricated sigmoidoscope into the anus and slide it through the rectum into the lower intestine. 

Also Read About: Solitary Rectal Ulcer Syndrome

The doctor will then pump air through the scope to expand the colon for a better view of the colon walls. This might cause abdominal discomfort and mild cramps. Try taking a few slow deep breaths to reduce the cramps. 

The video camera attached at the tip of the sigmoidoscope displays images on a monitor. The doctor will slowly withdraw the tube and carefully study the inside of your colon by viewing these images. If any abnormal growth or polyps are detected, the doctor will insert instruments through the scope to take tissue samples or remove polyps.

After the test, your doctor will discuss the results with you. You can return home after the test and carry on with your regular activities and diet. You may experience stomach pain, cramps, or bloating for some time after the test. If polyps are found, the doctor might recommend a complete colon exam, i.e., colonoscopy, as more polyps may be present further up in the colon. 

A small amount of rectal bleeding after the test isn’t alarming. But reach out to your doctor if you continue to pass blood or blood clots or have a high fever, or the abdominal pain hasn’t reduced.

What are the possible results of flexible sigmoidoscopy?

The results of flexible sigmoidoscopy are available immediately. Your doctor will review and discuss the reports. The results can be negative or positive. The result is negative if no abnormalities were detected in the colon during the test. The doctor may recommend repeating the test after five years, depending on the risks related to your age. 

Positive results, on the other hand, indicate that polyps or abnormal tissues were detected in the colon. This requires further testing, such as a colonoscopy, so that abnormalities can be more thoroughly examined, biopsied, or removed. At times, tissue samples are sent to a lab for testing. In such cases, it can take up to two weeks to get the biopsy results.


Flexible sigmoidoscopy is a minimal risk test performed by trained specialists to detect problems related to your colon and rectum. But the test does not provide a full view of the entire colon. Due to this, it cannot screen cancer or tiny lumps of cells that could turn cancerous farther into the colon. Discuss the pros and cons of flexible sigmoidoscopy with your doctor. It will help you choose an option that suits you the best. 

Frequently Asked Questions

Do I have to fast before a flexible sigmoidoscopy? 

Yes. Your bowel has to be cleansed for a successful sigmoidoscopy. You should have to consume a liquid diet the entire day before the test and not eat or drink anything after midnight. Any residue can obstruct the screening of the colon lining. You may also be given a laxative and enema to clear your bowels before the flexible sigmoidoscopy. 

What is the difference between a flexible Sigmoidoscopy and Colonoscopy?

Flexible sigmoidoscopy and a colonoscopy are recommended to screen the colon. A sigmoidoscopy is a less invasive test that allows screening of only the lower part of the colon. A colonoscopy allows viewing the entire large intestines. Your doctor can view and remove polyps in your lower colon through flexible sigmoidoscopy. During a colonoscopy, additional polyps are removed before they turn cancerous.

Why is Flexible Sigmoidoscopy performed? 

The test is also done before certain surgeries or to examine the causes of symptoms, such as bleeding, changes in bowel habits, colitis, changes in stool form or color, and diarrhea. 

Verified By Apollo Doctors
At Apollo, we believe that easily accessible, reliable health information can make managing health conditions an empowering experience. AskApollo Online Health Library team consists of medical experts who create curated peer-reviewed medical content that is regularly updated and is easy-to-understand.

Quick Appointment



Book ProHealth Book Appointment
Request A Call Back X