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Counties Manukau Health Gastroenterology and Hepatology

Public Service, Gastroenterology & Hepatology (Liver)


It can often be difficult to diagnosis gastric problems based on symptoms alone, for this reason your doctor has ordered a colonoscopy to confirm the diagnosis of your condition. 
A colonoscopy is an examination that involves using a long flexible tube that is small enough to enter via the rectum and travel through the bowel.  This enables the doctor to see the inside of your bowel.
What Happens Before the Colonoscopy?
The colonoscopy is performed either at the Endoscopy Unit at Middlemore Hospital Department of Gastroenterology or at Manukau SuperClinic. Your doctor will explain the procedure to you prior to your examination and will get you to sign a consent form, saying that you agree to have the procedure.
Before the procedure takes place, your bowel needs to be completely clear of faecal matter. To accomplish this you must follow these instructions carefully:
(1)  On the afternoon before your test you will be asked to drink 3-4 litres of a preparation called ‘Klean Prep’.  This works by cleaning the bowel and causes you to frequently go to the toilet.
(2)  It is important that your bowel return is “clear” for us to be able to safely perform the procedure.  This means there has to be no particles and the return should be a urine colour.  Your nurse will want to know what your bowel return is like.  You will need to drink the bowel preparation until the return is clear.
(3)  You should not eat or drink anything for at least 6-8 hours prior to the examination.
How Long Does the Examination Take?
The test itself is usually takes between 30-45 minutes.  However, depending on your case and the findings, may take slightly more time.
What Happens During the Colonoscopy?
You will be taken on a bed into the procedure room where you will be asked to lie on your left hand side.  An instrument that measures your pulse and oxygen levels will be placed on your finger.  A sedative will be given via the drip in your arm or hand to help relax you – it will not put you to sleep completely.  You will be given an oxygen mask to wear throughout the procedure.
The doctor will then start the examination.  To help in moving the scope (tube) around the bowel you may be asked to change your position and the nurse may have to apply pressure to parts of your stomach.  If required a biopsy may be taken during the procedure.  A biopsy is when a small amount of tissue is taken from the lining of the bowel and examined later.  You will not feel the biopsy being taken.
What Happens After the Colonoscopy?
You will be taken on your bed into the recovery room.  Here the nurse will check your blood pressure and pulse.  You will be given time to wake before getting changed and going home.
After the examination you may feel a little drowsy as the sedative wears off.  You can usually eat and drink straight after the examination.  It is normal to experience some gas pains caused by the use of air during the procedure.  A walk can sometimes relieve this bloated feeling.  The results of the examination will be sent your doctor and these and any treatment details will be discussed with you at a later date.
Are There Any Risks?
As with any procedure there are risks but these are very rare and a colonoscopy is considered one of the safest medical procedures you can have.  Risks may include, bleeding, perforation of the bowel lining and discomfort.  Your doctor will discuss these with you, before you sign the consent form.

This page was last updated at 12:13PM on June 28, 2021.