How It Is Done
Colonoscopy may be done in a doctor's office, clinic, or a hospital. The test is most often done by a doctor who works with problems of the digestive system (gastroenterologist). The doctor may also have an assistant. Some family doctors, internists, and surgeons are also trained to do colonoscopy.
During the test, you may get a pain medicine and a sedative put in a vein in your arm (IV). These medicines help you relax and feel sleepy during the test. You may not remember much about the test.
Before the test
You will need to take off most of your clothes. You will be given a gown to wear during the test.
You may lie on your left side with your knees pulled up to your belly. Because you will be given medicine during the colonoscopy, you probably won't remember much, if anything, until you wake up after the procedure.
Next, the doctor will insert a thin, flexible colonoscope in your anus and move it slowly through the rectum and into your colon. Air will be used to inflate your colon so the doctor can look at the lining of the colon through the scope or on a computer screen hooked to the scope.
During the test
You may feel the need to have a bowel movement while the scope is in your colon. You may also feel some cramping. Breathe deeply and slowly through your mouth to relax your belly muscles. This should help the cramping. You will likely feel and hear some air escape around the scope. There is no need to be embarrassed about it. The passing of air is expected. You may be asked to change your position during the test.
Your doctor will look at the whole length of your colon as the scope is gently moved in and then out of your colon.
The doctor may also use tiny tools, such as forceps, loops, or swabs, through the scope to collect tissue samples (biopsy) or take out growths. Usually, people do not feel anything if a biopsy is done or if polyps are taken out.