OGD stands for oesophago-gastro-duodenoscopy, sometimes also called a gastroscopy. An OGD test is performed for both diagnostic and therapeutic reasons. The test is commonly done with sedation. The alternative option to sedation is a local anaesthetic spray to numb the back of the throat, which can be combined with sedation if necessary.

Common reasons for the test:

1. to diagnose upper gastrointestinal (GI) tract ulcer disease that may cause pain or vomiting symptoms
2. to diagnose a tumour in the presence of ‘alarm’ symptoms including vomiting blood (haematemesis), difficulty swallowing (dysphagia) and weight loss
3. to look for an upper GI cause of iron deficiency anaemia
4. diagnosis and surveillance of Barrett’s oesophagus
5. diagnosis and treatment of varices (dilated oesophageal veins in chronic liver disease)
6. treatment of oesophageal narrowing (stricture)


The alternative test to OGD for reasons 1 & 2 above is a barium/x-ray contrast examination. This is less informative in making a specific diagnosis and has the disadvantage that tissue samples (biopsies) cannot be taken.

Preparing for the test

Stop clopidogrel (7 days) or warfarin (5 days) before the test if instructed, and temporary heparin injection may be necessary

On the day of test

Fasting (nothing to eat) for 6 hours before the test
Small amounts of clear fluid or water are safe up to 2 hours before the test
Blood sugar (BM) is checked in patients with diabetes mellitus
If sedation is requested, a cannula (small plastic tube) is inserted into a vein

In the endoscopy room

If sedation is requested, a monitoring probe is attached to a finger, and a nasal cannula attached to a nostril for oxygen supplementation
Denture (if present) is removed
Plastic mouth guard is applied
Endoscope is introduced into the mouth

Drugs commonly used for the test

Topical spray - Local anaesthetic throat spray
Injection - Sedatives (benzodiazepine, midazolam)

Patient position during the test

Left lateral (see picture 1)

Picture 1

Can I watch the test?

This is not feasible as the head position faces away from the video monitor.


You won’t feel any pain from having some biopsies taken.

If dilation of gullet (oesophagus) with a graduated tapered dilator (bougie) or an inflatable pressure balloon is performed, this may cause some discomfort. When a stent (a tube made of flexible metal mesh) is used to treat narrowing (stricture) due to tumour, the discomfort in the chest or back can last up to 3 days.

Injection of additional sedative or painkiller (morphine) drugs will be given as necessary during the tests for adequate control of pain or discomfort.

Specific complications

In OGD performed for diagnostic reason, the complications of perforation (tear of the linings of oesophagus or stomach) or bleeding occur extremely infrequently (less than 1 in 1000 cases).

For oesophageal dilation, there is approximately 1% risk of perforation, which may require surgery. The risk is higher (up to 10%) in the presence of tumour.

If there is any suspicion of the above complications during or straight after the test (in recovery), patients will be admitted for close monitoring and/or treatment.