Gastroscopy (OGD)

What is Gastroscopy (OGD)?

A gastroscopy is a procedure to look inside the oesophagus, stomach and the start of the small intestine (duodenum) and examine its lining. Gastroscopy is also known as upper GI endoscopy or Oesophago-Gastro-Duodenoscopy (OGD). Gastroenterologists are the specialists that perform this procedure. They have received special training to carry out this procedure and to diagnose oesophageal, stomach and duodenal diseases. The gastroscope is a flexible tube that is long and thin, about the width of a finger. It is inserted through the mouth. The tube has a camera and light attached on the end to allow the live viewing and visual images, which will be displayed on the screen. The examination is done under moderate sedation, which means the patient will not be conscious during the procedure.


The gastroenterologist will pass the gastroscope through the mouth into the oesophagus, stomach and duodenum. The upper digestive tract is washed clean and examined in detail. A gastroscopy usually takes about 10 minutes. 

Procedures that are performed via instruments that are passed through the scope are indicated below:

  • Biopsies: Tissue samples can be obtained in a systematic manner or guided by enhanced imaging systems
  • Polypectomy: precancerous growths can be removed with the use of snares.
  • Hemostasis: various devices such as heater probes, clips, bands and sprays can be used to stop internal bleeding 
  • Foreign body removal
  • Feeding tubes may be inserted
  • Dilatation and stenting: blockages may be bypassed
WHEN Should I Get The Procedure

Gastroscopy is used to investigate certain digestive symptoms before diagnosing oesophageal, stomach and duodenal diseases.  These symptoms include:

  • Upper abdominal pain or discomfort
  • Persistent or recurrent nausea and vomiting
  • Reflux symptoms such as heartburn, acidic taste and throat symptoms
  • Difficulty swallowing
  • Blood present in vomit or black stools
  • Unexplained weight loss
  • Iron deficiency anaemia

Gastroscopy is also the primary tool for stomach and oesophageal cancer risk assessment and prevention. This is proven to prevent such cancers in patients who have high risk factors. Gastroscopy can detect precancerous areas, which can be removed during the procedure to prevent them from becoming cancerous.

PREPARING For The Procedure

You should fast for at least 6 hours prior to your gastroscopy. You may drink clear fluids up to 2 hours before the procedure. Prolonged fasting may be needed if your doctor suspects that your stomach is not completely emptied. 

In general, most medications can be continued before the procedure with the exception of diabetic  medications and blood thinners. Diabetic medications should be omitted during the fasting. You should check with your doctor if your blood thinner needs to be ceased prior to the procedure.

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

BEFORE The Procedure

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

DURING The Procedure

A throat spray will be administered to attenuate the discomfort of the procedure. A plastic mouth piece will be placed between your teeth for dental protection. You will be positioned to lie on your left. Sedation will then be administered. After you have fallen asleep, the procedure will begin. It is likely that you will not remember any parts of the procedure. You will be breathing on your own and monitored closely during the procedure. Once the procedure has completed, you will gradually wake up.

AFTER The Procedure

You will be cared for in a recovery room. You will be monitored until you have regained consciousness from the anaesthesia. The nurses will give you food and drink after post-procedure assessments. You should arrange for a family member to take discharge instructions and take you home. You should only resume going to work and/or drive the following day. It is common to have mild sore throat, abdominal discomfort or bloating after a gastroscopy. This usually goes away after 24 hours.

Your doctor will fix an appointment to explain the gastroscopy procedure and findings, including the results of any biopsies taken. He will then discuss the appropriate management plan.

SAFETY Of The Procedure

Gastroscopy is a very safe examination. Complications are rare and overall occur in less than 0.1% of cases. These are often due to disease factors. Such complications include tearing of the wall, bleeding and anaesthetic adverse reactions. Unfortunately, emergency surgery or urgent hospitalisation may be required. The risk may be higher in complex cases or those involving interventions. Your doctor will advise you on the complications, precautions, and on what to do should these events occur.

QUALITY Of The Procedure

Quality of gastroscopy is imperative and depends heavily on the specialist. A good specialist will have good photo-documentation of landmarks, and comprehensive report writing using international nomenclature. The specialist will customise the gastroscopy according to the symptoms or disease. In cancer screening, the specialist should be able to perform a risk assessment using international standards, and detect precancerous areas. A good quality control program will help assure patients that their gastroscopy meets the required international standards.

COST Of The Procedure

A gastroscopy is a hospital procedure, and is covered under most hospitalisation plans. It is also Medisave deductible. Many companies’ health benefits and private health insurances cover the cost of gastroscopy, which may extend to the private sector. The Ministry of Health provides fee benchmarks and publishes the average fees in each hospital. Before any endoscopic procedure, a detailed financial counselling is done to help patients understand the cost breakdown. Patients should check with their insurance provider and do their own research before seeing a specialist.