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Colonoscopy

Understanding and preparing for a colonoscopy screening

During a colonoscopy, a flexible tube is advanced through the anus and rectum into the large intestine (colon). This procedure allows the doctor to examine the inner surface of the large intestine and identify any diseases or abnormalities that may exist. It's frequently done to look for and remove polyps, look for sources of bleeding, look for causes of abdominal pain, or as a screening test for colon cancer. 

Who should have a colonoscopy?

According to the American Cancer Society guidelines, ALL adults (men and women) should start colonoscopy screenings for colon cancer at age 50. If you are over age 50 and have never had a colonoscopy, start now. African Americans may run an increased risk at an earlier age and should begin screening at age 45. If you have a history of colon cancer in a parent, sibling or child, you may need to have a colonoscopy at an earlier age. There are also certain hereditary conditions that may require screenings at an earlier age. Always discuss your history with your doctor.

What happens during a colonoscopy?

Upon arriving at the GI facility, you will be taken to a room and asked to change into a gown. The nurse will review your health history and ask if you have any allergies. An intravenous line (IV) will be placed in your hand or arm vein before the procedure. Medicine will be given through this IV line to make you sleepy and relaxed during the test.

In the procedure room, you'll be asked to lie on your left side. The doctor will examine your anus and rectum with his finger and he (she) will then pass the colonoscope into the rectum and into the large intestine. The doctor will put air into the colon through the colonoscope to help look at the inside surface. This will make you feel like you have to move your bowels or have gas. After the procedure, you will be asked to pass out the extra air (gas) while you rest.  At the end of the procedure, you will return to a room to rest and wake up from the medications.

How long does a colonoscopy take?

The length of time varies for a colonoscopy. The average time is approximately 30 minutes. This exam could take one hour or longer in some people. Please feel comfortable in knowing that although some exams may take longer and set back your procedure time, your doctor will give you a thorough exam.

Plan to spend three to four hours in the GI facility, although it usually does not take this long.

How do I prepare?

All colonoscopies require that your colon be clear of all stool and fecal matter. To accomplish this, you will be asked to take a laxative preparation. There are different preparations available. Some require a prescription from your doctor. You will be asked to have only clear liquids the day prior to your exam. At some time in the afternoon or early evening you will start to take your pill and /or liquid preparation. It is important that you follow the instructions. If your colon is not clear, the doctor may miss polyps or other lesions. If you have any questions or difficulties with your preparation, call and discuss with your doctor. 

What is a polyp?

Polyps are lumps of tissue in the lining of the rectum and colon. In early stages polyps produce no symptoms. You cannot feel them and they do not cause bleeding or pain when they are small. Some polyps can stay in your colon for a lifetime and never cause a problem. Other polyps can be ‘pre-cancerous" - they may turn into a cancer (tumor) if left in your colon. Your doctor is not able to determine which polyps may turn into a cancer. For this reason, all polyps are removed during a colonoscopy. There are different methods for removing a polyp. It is important that you inform your nurse or doctor if you have been taking a blood thinner or aspirin. It is also important to notify your doctor if you have an automatic implanted cardiac defibrillator (AICD) in place.

When will I get the results of my colonoscopy?

Your doctor will, in most cases, talk with you after the exam. Because of the sedation effect of the medication you receive, you may not remember everything your doctor tells you. It is recommended that you have someone with you to also hear what they say. Your nurse will write the findings on your discharge papers. Most doctors will call you or send a report to you if a polyp was removed or biopsy was taken. These results can take up to three weeks.

More information

Visit our Health Encyclopedia for more information about Colonoscopy.