A colonoscopy is an exam used to detect changes in the large intestine (colon) and rectum. It can be used to investigate signs and symptoms of intestinal problems, to monitor for early tell-tale signs of colon cancer, and to look for polyps in order to reduce the risk of colon cancer.

Before colonoscopy you will need to follow specific instructions for cleaning out the bowel so that the camera at the end of the colonoscope will be able to give clear images of the bowel wall.

How is the test done? If you wish, you will be sedated. You will then be asked to lie on your side. A flexible tube about the diameter of a finger is inserted through the anus into the rectum and around the colon. Samples (biopsies) of the lining can be taken through the tube for examination.

Please note that Colorectal Cancer Awareness Month is held in March each year.


Reasons for colonoscopy


How long does the procedure take?

It is a day-case procedure. It takes about 15–30 minutes but plan to spend 2–3 hours to include recovery time.


How do I prepare for a colonoscopy?

Careful preparation is essential for a successful examination. If your bowel is not cleaned out before the exam, the doctor will not be able to detect any problems. You will be prescribed an oral laxative (a ”bowel prep”) to clean out your bowel. This usually means drinking a certain amount of fluid to flush out the bowel. Read your prep instructions carefully so that you know what you should do the day before and on the day of the test.


Is the test uncomfortable?

Not usually, but you can minimize any discomfort (for yourself and for your doctor) if you clean out the bowel fully. A short-acting sedative is usually given intravenously. This is not general anesthesia and you will not be unconscious, but most patients are comfortable. You will not be allowed to drive after the sedative and will need to arrange for a driver to take you home.


Is colonoscopy covered by private insurance?

Most insurance companies cover colonoscopy if it is performed for conventional reasons.




Are there any complications or risks?

It is generally safe, but there are risks associated with the procedure and with the sedation, which are uncommon. Perforation or puncture of the bowel is the most serious risk but is rare. Bleeding may occur at the site of a biopsy or if a polyp is removed.

Some patients react adversely to the sedation, but you will be monitored for this and an antidote can be used. If you have any concerns that there is something wrong after the test, you should contact your doctor or return to the hospital.


Will the drugs I’m on affect the test?

Most medications do not affect colonoscopy. However, if you are on insulin, your dosage may need to be adjusted because you will need to fast for several hours before the procedure. If you take blood-thinning drugs, they may have to be stopped or adjusted before the procedure to allow for biopsy and/or polyp removal. Discuss this with your doctor.


Can I go back to work the next day?

Yes. You will need to take a day off work to have the procedure. Some patients who work evenings also take off the day before the procedure to do the bowel prep.


Does menstruation affect colonoscopy?

No. Tampons can be worn if you wish and will not affect the procedure.


When will I get the results?

Your doctor will be able to give you a provisional result after the test, but the results of the biopsies can take several days. You will be asked to see your doctor to discuss the test results on another day.


Information based on Fast Facts for Patients and their Supporters: Inflammatory Bowel Disease (Karger, 2019).

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