Colonoscopy Screening in 2022: A Guide by Dr Ganesh Ramalingam

Dr. Ganesh Ramalingam is the original author of this article, which was first published on 17th January 2022.

This current article is an updated version by Dr. Ganesh.

Colorectal cancer is the most prevalent cancer in Singapore with around 1200 new cases every year.1 Male Chinese Singaporeans are at the highest risk of colorectal cancer. 

Early screening via colonoscopies can detect them and improve the likelihood of recovery. 

So, what does a colonoscopy entail and how do I prepare for it? Is it Medisave claimable? This ultimate guide will give you a detailed insight into colonoscopy in Singapore.

What is colonoscopy?

A colonoscopy is a form of endoscopy where a video camera is inserted using a tube (together called a scope) into the large intestine (colon) and rectum to examine for abnormalities and diagnose gastrointestinal conditions. The doctor views the inside of the colon and can remove polyps or tissue samples through the colonoscope.2

You may read my previous article on colonoscopy over here:

Illustration of Colonoscopy

When will I need a colonoscopy?

You may need a colonoscopy for the following reasons:3

To determine the cause of the signs and symptoms

 If you’re having abdominal pain, rectal bleeding, chronic constipation, chronic diarrhoea or other intestinal problems, your doctor may use a colonoscopy to help diagnose the condition. 

Read to find out the link between abnormalities in your bowel movements and colon cancer. 

For colon cancer screening 

Colonoscopy is an option to screen for colon cancer. If you’re aged 50 and above with risk factors for colon cancer, you may want to get a colonoscopy to screen for colon cancer. 

To find and remove polyps 

Your doctor may recommend a colonoscopy if you have had stomach polyps before and want to see if there are any additional new polyps. This reduces your risk of colon cancer. 

How to prepare for a colonoscopy procedure?

You will be required to empty your colon before the colonoscopy procedure. This is because any residue may block the view of the colon or the rectum during the examination. Your doctor may request for you to do the following: 

Follow a special diet 

You are advised to avoid any solid foods the day before the procedure. For drinks, you may only drink clear liquids, such as plain water, coffee or tea without milk or cream and carbonated beverages. Red liquids are to be avoided as they may be confused with blood during the examination. After midnight on the night before the colonoscopy, you will not be allowed to eat or drink anything. 

Use a laxative 

Your doctor will usually ask you to take a laxative either as a pill or a liquid. It will be taken the night before or you may be asked to take the laxative on both the night before and the morning of the procedure. 

Use an enema kit 

You might need an over-the-counter (OTC) enema kit to empty your colon. However, it is not the preferred way to empty the colon as it only empties the lower colon. 

Temporarily stop your medications 

If you have high blood pressure, diabetes or heart problems and are on medication, let your doctor know. Also, inform your doctor of any medications that contain iron or thin the blood and reduce clots. You may need to adjust the dosage of your medication or temporarily stop taking them. 

What happens during a colonoscopy?

Lady going through colonoscopy

During the colonoscopy, you’ll be wearing a gown and sedation will be given, sometimes in the form of a pill or in other cases in combination with intravenous pain medication. 

You will lie on your side on the exam table with your knees up towards your chest. Then, the doctor will insert a colonoscope into your rectum. 

The scope is long enough to extend into the entire length of your colon and contains a tube that allows the doctor to pump air or carbon dioxide inside so that it can inflate the colon for better visualisation of the colon. 

When the doctor moves the scope or pumps air into the scope, you may feel a cramping sensation or the urge for a bowel movement. This is normal and nothing you have to worry about. 

The colonoscope is also equipped with a small camera that sends an image to a computer for the doctor to view your colon. Your doctor may insert other instruments through it to remove polyps or take tissue samples. A colonoscopy may take 30-60 minutes to complete

Illustration of an human body anatomy going under Colonoscopy

What happens after a colonoscopy?

As it takes about 1 hour for the effects of the sedative to fade, please ensure that someone brings you home because the sedative needs up to a day to wear off completely. Do not drive or return to work yet for the remaining day. 

If you’ve had a polyp removed during the colonoscopy, you will be advised to have a special diet for a short period of time. 

If you had a biopsy or polyps removed, your doctor will inform you4

  • Regarding the results of the biopsy.
  • If you need to avoid aspirin or other blood-thinning medication.

You may feel some bloating or need to pass gas a few hours later to clear air from your intestines. It may help to walk around. 

You may also see a little blood during your first bowel movement after the colonoscopy – there is no need to be alarmed! 

However, let your doctor know if this continues to happen or if you have persistent abdominal pain or start to have a fever. Albeit rare, these side effects may happen early after the colonoscopy or be delayed for up to 1-2 weeks – so constantly keep a lookout. 

Otherwise, your bowel movements will return to normal within 2-3 days. Most patients can return to their normal diet and activities the following day. 

What are the risks of getting a colonoscopy?

A colonoscopy doesn’t have many risks as it is a very safe examination, but rarely, some complications may arise, including: 

  • Adverse reactions to the sedative.
  • Bleeding in the area where the tissue sample or polyp was taken. 
  • A perforation or tear in the wall of the colon or rectum. 

What is the cost of getting a colonoscopy in Singapore?

Public hospitals with subsidies$300-$830
Restructured hospitals$1100-$2500
Private hospitals$1800-$2600

Note that if biopsies or polyp removal is required, there may be additional costs due to the need for additional equipment and testing.

Can I use Medisave to pay for my colonoscopy?

Medisave may be used for a screening colonoscopy subject to the prevailing TOSP (Table of Surgical Procedures) withdrawal limit for colonoscopy procedures plus $1200-$1600 per day for any associated day surgeries.5

Singaporeans and permanent residents aged 50 years old and above may use up to $1250 from their Medisave to pay for the procedure at all public healthcare institutions and approved private hospitals and medical institutions.6

Is colonoscopy insurance claimable in Singapore

All 7 Integrated Shield Plan (IP) insurers in Singapore provide coverage of diagnostic endoscopies, including colonoscopies.7

Why should I get regular colonoscopies?

Routine colonoscopies can help to detect colon cancer so that you are treated early for better chances of recovery. It can also help to diagnose any gastrointestinal problems before they get worse. 

Colonoscopies should be done at the age of 50 for most people. If you do not have any risk factors or there are no polyps during the first examination, the next one should be in 10 years. If you have slightly higher risk, you should get one every 5 years. If you are at high risk, consult your doctor to see how often you should be screened. Routine screening is usually not needed after age 75.8

RiskScreening frequency
Low risk/no riskEvery 10 years
Medium riskEvery 5 years 
High riskDepending on condition and doctor

Misconceptions of colonoscopies

Misconceptions regarding colonoscopies are dangerous because they confuse people and prevent them from going for screening. Here are some misconceptions about colonoscopies that you should be aware of: 

“A polyp means I have cancer.”

A polyp is a non-cancerous growth and it may appear in the large intestine. Over time, such growths may develop into something cancerous. While they are the precursors to cancer, they do not indicate that you have cancer. The main goal is to remove them so that your risk of colon cancer is reduced. 

“I have no symptoms so I do not need a colonoscopy.”

Colon polyps usually do not have any symptoms until they worsen. The colonoscopy can remove these polyps before they turn cancerous. So, even if you do not have symptoms, you may still have polyps that require removal. If you have symptoms like rectal bleeding or constipation or diarrhoea, arrange for a colonoscopy with your doctor. 

“A colonoscopy is painful.” 

While you may feel some pressure or cramping during the colonoscopy due to the air used to expand the colon, sedatives are used so you should not feel any pain. In fact, you will likely be sleepy and comfortable.  

“The risks of colon perforation and bleeding outweigh the benefits of a colonoscopy.”

A colonoscopy is a very safe procedure. In rare cases, the endoscope may puncture the colon or rectum wall and cause it to be perforated. This usually requires surgery to resolve. However, the risk of perforation is less than 1 in every 10 000 patients, which is extremely low. Rectal bleeding may also occur in rare cases, but it is typically minor and resolves by itself. Overall, it is safe to say that the benefits of a colonoscopy far outweigh the risks


I hope you’ve found this guide helpful and gained a better understanding of colonoscopies and the role they play in early prevention. 

Regular screening can save lives and give peace of mind. I always tell my patients – prevention is better than cure; you never know when a simple colonoscopy can save your life. 

If you have any questions or would like to seek treatment for colonoscopy, feel free to contact me and I’ll be happy to help.

Dr Ganesh Ramalingam is a general surgeon in Singapore with a special interest in gallbladder disorders, hernias, bariatric, and laparoscopic procedures. To date, he has performed over 6,000 colonoscopies, which has helped him diagnose and treat patients with colon and rectum diseases.

As someone who writes passionately about his medical practice, Dr Ganesh is the author of 15 original articles in various peer-review journals and more than 60 poster and oral presentations at conferences.


  2. Stauffer, C. M., & Pfeifer, C. (2021). Colonoscopy. StatPearls [Internet]