In Colonoscopy test, a doctor passes a thin tube (endoscope / colonoscope) to examine the inner lining of large intestine, which consists of the colon and the rectum.

Colonoscopy is done to detect polyps, bleeding ulcers, tumors, or inflamed areas. It can also be used to find the causes behind abdominal pain, irregular bowel habits, or sudden rectal bleeding. Colonoscopy is also one of the standard procedures for screening colorectal cancer.

Colonoscopy and colorectal cancer:
Timely colonoscopy can help detect a colon cancer in the early stage to prevent further spreading of the disease. People between 45 and 50 years of age, and at high risk of developing colon cancer should get a colonoscopy done once in every five to 10 years. Periodic screening tests may actually reduce the risk of pain or fatality associated with colon cancer.

Preparing for a colonoscopy
Before conducting a colonoscopy, your doctor needs to know if you are suffering from any of the following conditions: lung disease, heart ailments, medicinal allergies, diabetes, or pregnancy. Other preparatory requirements may include:

Special diet and fluid intake with restrictions on solid food
Oral laxatives
Enemas before the procedure to clear the rectum and lower intestine
Sedative during the procedure
Arranging for a driver to bring you home after the test.

The general procedure for colonoscopy

The colonoscopy procedure can be done either in a doctor’s office or in a local hospital. It usually lasts between 30 to 60 minutes. Here are the steps involved in colonoscopy test:

An intravenous channel will be created in a vein in your arm.
You will be administered a sedative and a pain killer through the IV channel.
You will be instructed to turn to your left side on the examining table with your knees drawn closer to the abdomen.
The doctor will insert a ½ “-diameter colonoscope through your rectum, which will extend to the end of the large intestine.
While checking for abnormalities with a gloved finger into the anus, the doctor will use the “colonoscope” to transmit an image of the inner lining of the colon to examine any polyp, bleeding ulcer, tumor, or inflamed area present in the colon.
In case there is blood, stool, or secretion blocking the view inside the intestine, the blockage will be cleared through the colonoscope.
Your entire large intestine can be examined through a colonoscopy. Usually, if the doctor detects any abnormality during a colonoscopy, he or she will insert special forceps or brushes into the colon to obtain tissue samples. After a colonoscopy, the colonoscope will be gradually withdrawn and the air will be released. Your anal area will be cleaned with tissues.

Note: Although patients do complain about general discomfort and pressure during the test, colonoscopy procedure is not painful.

A procedure called virtual colonoscopy involves computer imaging or CT scans to produce images of the inner lining of the colon is offered as a less invasive substitute for colonoscopy. However, most doctors prefer conducting a regular colonoscopy as a follow-up procedure for virtual colonoscopy if any abnormality is discovered during the computerized imaging procedure.