colonoscopy is a procedure to look inside your colon and examine its lining. Gastroenterologists are the specialists that perform the colonoscopy. In Singapore, they receive special training to carry out the procedure and also to diagnose various diseases.

The main tool used to look inside the colon is a colonoscope, which is a soft and flexible tube that is long and thin about the width of a finger. The colonoscope is gently inserted into the anus and is long enough to look at the entire large bowel and the lower part of the small intestine. The tube has a tiny camera and light attached on the end to allow the live viewing and visual images of the colon to be displayed on the screen. The examination is done under moderate sedation, which means the patient will not aware during the procedure.


The large intestine, or colon, is the last part of the digestive tract. The colon is made up of a hollow tube about 5 feet long which takes in water and minerals from food that is digested. The colon starts at the cecum, at the end of the small intestine, and ends in the rectum where stool is stored at the last part of the large intestine.


The gastroenterologist passes the colonoscope through the anus into the colon until the end of the colon (caecum). Most of the time, the scope is also passed into the terminal ileum (the last part of the small intestine).

The colon is not straight and passing the scope to the caecum requires combinations of special techniques such as:

  • Water immersion technique: a technique that uses water immersion to facilitate insertion of the colonoscope
  • Sigmoid pressure: The nurse would apply pressure on the abdomen during the procedure. This is used very sparingly to facilitate insertion of the colonoscope only for selected cases.
  • Shortening of the scope and loop reduction
  • Changing of the position of the patient
  • Stiffening of the scope using special knobs

Colonoscopy usually takes no more than 30 minutes. A well-trained gastroenterologist should be able to advance the colonoscopy to the caecum in 5 minutes on average. He should spend at least 6 minutes inspecting the colon when withdrawing the colonoscope.

Procedures can be performed through instruments that are passed through the gastroscope:

  • Biopsies: These would be done in a systematic manner or guided by enhanced imaging systems
  • Polypectomy: large polypoidal lesions can be removed with the use of endoscopic snares.
  • Injection of marker dye
  • Argon-plasma-coagulation (APC) can be used to obliterate small bleeding vessels or lesions.
  • Hemoclip application: Commonly used to stop bleeding from arteries.
  • Hemospray can be used to stop upper digestive tract bleeding.
  • Removing foreign body
  • Performing dilatation and stenting (for the advanced endoscopist only)


Colonoscopy is a safe and effective method to investigate digestive symptoms and it is essential in the management of some digestive illness.

Some digestive symptoms that may need the colonoscopy to investigates are:

  • Change of bowel habit
  • Blood in stool
  • Unexplained loss of weight
  • Abdominal pain or bloatedness
  • Chronic diarrhea
  • Chronic constipation
  • Iron deficiency anemia

Some colonic illness that may need colonoscopic examination at some points include:

  • Cancer of the colon
  • Colonic polyp
  • Ulcerative colitis
  • Crohn’s disease
  • Diverticulosis
  • Angiodysplasia of the colon

It is also the primary tool for colon cancer prevention. Colon cancer is one of the leading causes of cancer deaths worldwide including Singapore. Anyone with a moderate risk of colon cancer (such as a person above the age of 45) would need a colonoscopy to see if there are any colonic polyp. Polyps are mushroom-like tissue growths that occur on the inside wall of the colon or rectum, and they can grow slowly over the years and become cancer. Once detected, the polyps will be removed (a process called polypectomy) during the colonoscopy and colorectal cancer would be prevented.

Preparing for Colonoscopy

You should fast for at least 6 hours prior to your colonoscopy. You may drink clear fluid up to 2 hours before the procedure but milk is not allowed during the fasting.

You will be given medication to pass motion to prepare fore the colonoscopy. This is commonly known as bowel preparation. You should follow the instruction of the bowel preparation given to you.

In general, most medication should be continued before the colonoscopy with the exception of diabetes medication and blood thinners. Diabetic medication should be omitted during the fasting. You should check with your doctor if your blood thinner needs to be discontinued prior to the procedure.

As you will be given medication to make you sleepy, you must not drive, work or make any important decision after the procedure. Medical Certificate will be issued if needed and you should rest at home for the rest of the day.

Before the Colonoscopy

A nurse will conduct final checks, and bring you into the procedure room. An intravenous line will be inserted.

During the Colonoscopy

You will be lying on your left, with your legs curled up.

Sedation will then be given. After you have fallen asleep, the procedure will begin. You will likely not remember any of the procedure. You will be breathing on your own and monitored closely during the procedure.

You will wake up gradually after the procedure is done. All the medication used for sedation have a duration of action of a few minutes.

After the Colonoscopy

You will be cared for in a recovery area or room. The nurses will give you food and drink when they assessed that you are ready. You should arrange for a family member to take discharge instruction and take you home. You should only resume working and driving the following day.

Sometimes, you may have a mild sore throat, bloating and cramp. This normally goes away after 24 hours.


Colonoscopy is a very safe examination. Complication happens only very rarely.

Despite the best of intention and effort, sometimes issues do happen. There are:

  • A tear in the intestinal wall (which may need surgery to fix)
  • Bleeding
  • Allergic reaction to medication

If you have any concern after the colonoscopy, you should contact your doctor.


Quality of colonoscopy matters. A good specialist should have caecal intubation rate above 95% and adenoma detection rate above 25%.

A good bowel preparation is important. The stool should be watery and without any solid particle after adequate bowel preparation. Good bowel preparation can be achieved with 3 to 4 liter of PEG or 3 packets of picoprep.

Some bowel prep that includes sodium phosphate (oral fleet) may have significant side effects including permanent kidney failure and they should only be used under very strict supervision.

Good documentation should include pictures of the terminal ileum, ileocecal valve, and appendiceal orifice. The pictures should be clear and of good quality.

Cost Of Colonoscopy And How To Choose

A good proportion of the cost of the colonoscopy is covered with Medisave deduction in Singapore.

Many company health insurances and private health insurances actually also do cover the entire cost of colonoscopy in most cases, which includes specialist clinics or private hospitals. Many people may not be aware of the health care benefits offered by their own company hence it is recommended that you check with yours.

The charges of the various private hospitals and clinics also differ. You should do some research to compare prices before making a decision.

Different private doctors charges differently for the colonoscopy procedure, which depends on their level of experience and the demand for their services. You are able to check their fees against the “Total Operation Fees” published on the Ministry of Health web page. Financial counseling is often done prior to any colonoscopy.

Click here to find out on the preparation of your procedure. 

Endoscopy, Services

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