Everything you need to know about having a gastroscopy

A gastroscopy is a procedure to examine the inside of your gullet (oesophagus), stomach and the first part of your small intestine (duodenum). During this procedure, tissue samples (biopsies) can also be collected and certain treatments administered. 

Also known as an upper GI endoscopy or oesophagogastroduodenoscopy (OGD), it involves passing a thin, flexible tube with a light and a camera on the end (gastroscope) through your mouth or nose and down your throat. 

Why do you need a gastroscopy?

A gastroscopy is often used to diagnose the underlying causes of gastrointestinal symptoms, such as difficulty swallowing (dysphagia), newly developed or suddenly changed heartburn or acid reflux and vomiting. It is also used to investigate anaemia and unexplained weight loss. 

A gastroscopy can also be used to treat conditions after a diagnosis has been reached. For example, it can be used to widen (dilate) the oesophagus or remove polyps from the stomach. 

How to prepare for a gastroscopy

It is important that your stomach is empty before you have a gastroscopy. This makes it easier for your endoscopist (a person specially trained to perform endoscopy procedures) to view the inside of your gastrointestinal system. It also makes the procedure safer by reducing the risk of a chest infection from food or fluid entering your lungs during the procedure. 

You will usually be instructed not to eat or drink anything in the eight hours running up to your procedure. You may take sips of water up to two hours before your gastroscopy. 

If you’re taking certain medications (eg blood thinners or antacids), your doctor may advise you to temporarily stop taking them in the days before your gastroscopy. 

What happens during a gastroscopy?

A flexible, telescope-like device (gastroscope) will be passed through your mouth or nose, down your throat, into your gullet (oesophagus) and then onwards into your stomach and duodenum. 

A local anaesthetic spray will be applied to the back of your throat to help prevent your gag reflex, so the gastroscope can be more easily passed down. This part may feel uncomfortable but will only take a few seconds. 

If you’re feeling anxious, you may also be offered sedation through an intravenous drip placed in your arm. This will help you relax and in most cases, means you will not have a clear memory of your procedure. 

Once the gastroscope has entered your gastrointestinal system, air is pumped in to give your endoscopist a clearer view. This can make you feel bloated after your procedure and you may belch afterwards. 

Recovering from a gastroscopy

After your procedure, you’ll be taken to a recovery room so that the throat spray and sedation can start wearing off. Usually, within an hour, you will be given a hot drink and a biscuit. 

If you don’t have sedation, you can go home by yourself after your procedure. 

If you have sedation, you will need to be accompanied home by an adult and someone will need to stay with you for the next 24 hours — you should not drive or operate heavy machinery during this time. 

Your throat may feel sore and you may feel bloated for one to two days afterwards. If you experience any significant pain, contact your care team. 

Gastroscopy risks

Every invasive procedure comes with potential complications. Although a gastroscopy is generally considered safe, there are risks of an allergic reaction to the sedation, aspiration pneumonia (a chest infection due to food or fluid coming up from your stomach into your lungs), bleeding and perforation (poking a hole) of your upper gastrointestinal tract. 

In some cases, it may not be possible to complete your gastroscopy, for example, if you aren’t able to tolerate the procedure or due to anatomical reasons. 

Although a gastroscopy broadly gives your endoscopist a clear view of the inside of your gastrointestinal system, it is nonetheless possible to miss abnormalities. 

Your gastroscopy results

Your doctor will discuss what was found during your gastroscopy before you’re discharged to go home. 

If tissue samples were collected, depending on the tests needed, you may get the results on the day of your procedure (eg testing for Helicobacter pylori infection can be done immediately) or several weeks later (eg if the sample needs to be examined under a microscope).