Gastroscopy Singapore: A doctor’s guide on how it’s done

In medicine, procedures like CT scans and MRI scans help detect many diseases. However, for conditions involving the stomach, it’ll take more than just computerised scans to do the job. In Singapore, that’s when a gastroscopy comes in. 

A gastroscopy can help rule out or confirm the presence of conditions like stomach cancer, peptic ulcers or gastritis. In this procedure, a thin, flexible tube called an endoscope is lowered down the throat to look inside the food pipe, stomach and first small of the small intestine. The endoscope has a camera and light at one end which captures and sends images of your insides to a monitor. It can also take tissue samples by latching instruments such as small pincers, as well as suck out air and fluids.

Why a gastroscopy is done in Singapore

A gastroscopy is usually done to find out the cause of symptoms such as:

  • Chronic or recurring nausea, vomiting or heartburn 
  • Indigestion 
  • Difficulty swallowing 
  • Persistent stomach pain 
  • Blood in your stalls or black stools 
  • Unexplained weight loss

It can be used to:

  • Diagnose medical conditions like stomach ulcers or gastro-oesophageal reflux disease. This is known as a diagnostic gastroscopy. 
  • Treat medical conditions like non-canorous growths, bleeding ulcers, a blockage in the oesophagus or small cancerous tumours. This is known as therapeutic gastroscopy.

Preparing for a gastroscopy in Singapore

If you’re scheduled for a gastroscopy, your doctor may ask that you stop taking any prescribed medicine for indigestion about 2 weeks before the procedure. This is to stop the medication from masking some of the problems a gastroscopy can find. 

In addition, you should inform your doctor if you’re on any medication for diabetes, such as insulin or any blood-thinning medication, such as warfarin or clopidogrel. 

To ensure that your stomach is empty during a gastroscopy, you’ll usually be advised not to eating anything for 6 to 8 hours prior to the procedure, and to stop drinking 2 to 3 hours before. It’s important that you follow these instructions so your whole stomach area can be seen clearly during the gastroscopy.

What happens during a gastroscopy in Singapore?

A gastroscopy is usually carried out by an endoscopist and assisted by a nurse. Before the procedure, you’ll sign some forms. This is a good opportunity to ask any questions you have. 

Patients can choose to do the test under local anaesthesia or a sedative. Young children can opt to do it under general anaesthesia, which means they’ll be asleep while the test is carried out.

Having a gastroscopy awake under local anaesthesia

An endoscopist will spray the back of your throat with local anaesthesia to numb your mouth and throat. Any removable dentures should be taken out. The anaesthesia may taste a little bitter and make you cough. It will take a few minutes for your throat to go numb; during which, you’ll lie on your left side. A protective ring is put between your teeth to ensure your mouth stays open and you do not bite on the endoscope. The endoscopist will then pass the endoscope into your mouth and down your throat to assess the oesophagus. You’ll have to swallow for the endoscope to pass your throat. This may feel uncomfortable initially and you may gag or feel sick, but this should pass once the endoscope moves further down. The endoscope is slightly bigger than a pen. 

Once the endoscope is down, your doctor will examine your stomach lining and food pipe to look for any inflammation. Things like stomach ulcers, bleeding and unusually narrow passages will also be reflected on the screen. Air might be blown into your stomach to detect for any abnormalities — this may make you burp or feel bloated. If necessary, a tissue sample can be taken via the endoscope. You will not feel anything at all.

Having a gastroscopy under sedation/while drowsy

Once you lie down on the couch, your nurse will inject the sedative through a cannula into a vein in your arm. It’ll take a few minutes for you to get relaxed and drowsy. Once the sedative kicks in, the gastroscopy will be performed. During which, you’ll still be able to follow instructions by your nurse and endoscopist. 

You will also be given oxygen through a small plastic tube that sit inside your nostrils, as well as a clip on your finger to monitor your heart rate and oxygen levels.

After a gastroscopy in Singapore

After the gastroscopy, you’ll be informed on how the test went, if any biopsies were taken and when to expect results. If you opted for local anaesthesia, you’ll be able to go home shortly after. However, you won’t be able to eat or drink for about an hour or till the local anaesthetic spray wears off. 

If you opted for sedation, you have to stay in the endoscopy unit for about an hour or two to recover. You may not remember much about the test, and you’ll need someone to take you home. For the next 24 hours, you are advised not to:

  • Drive 
  • Drink alcohol 
  • Sign important documents 
  • Operate heavy machinery 
  • Take sleeping pills 
  • Go to work
Singapore doctors performing gastroscopy

Possible side effects of a gastroscopy in Singapore

A gastroscopy is a very safe procedure, but some possible risks of this procedure include:


You may get a small amount of bleeding if you have a biopsy, but this usually stops on its own. If it doesn’t, seek medical attention.


There is a very small risk that your wound can become infected after a biopsy, resulting in a high fever. If this happens, you should contact your doctor.

Sore throat

A sore throat is common after a gastroscopy. It should last for a few days, but contact the hospital if you experience severe pain.

Damage to teeth

There’s a small chance that the endoscope can damage your teeth. However, the mouth guard can prevent this from happening.

Chest infection

When you breathe in spit due to the sedation or from your throat being numb, it may result in a chest infection. To prevent this from happening, a nurse will suction away any secretions during the gastroscopy.

Sedative complications

Very rarely, sedatives can lead to breathing and blood pressure problems. These side effects are higher among those with heart or lung problems or in older people.

Waiting for results

Your results should be out in about 2 weeks. During this period, you may feel worried. To ease your anxiety, it can help to get contact details of a specialist or nurse any time you need more information. It will also help to speak to a close friend or loved one about how you feel.


  1. What happens during a gastroscopy? – – NCBI Bookshelf.(2015).
  2. Gastroscopy – NHS. (2018).