Gastroscopy (gastrointestinal (GI) endoscopy)

What is a gastroscopy?

A gastroscopy, also called an upper gastrointestinal (GI) endoscopy or OGD, is a test to look inside your throat, food pipe (oesophagus) and stomach, (the upper part of your digestive system).

A long, thin, flexible tube with a small camera and light on the end is passed through your mouth and down into your stomach so your doctor can see the lining clearly.

Why might I need a gastroscopy?

You might be offered a gastroscopy to find the cause of symptoms such as:

• indigestion or heartburn that hasn't improved with treatment
• difficulty swallowing, or a feeling of a lump in the throat
• persistent sore throat or a cough that's worse at night
• being sick, especially if there's blood
• losing weight without trying, or anaemia
• dark, tarry or black stools, which can be a sign of bleeding.

It can also be used to check an ongoing condition, such as Barrett's oesophagus or a previous stomach ulcer, or to remove tissue for testing (biopsy) and treat some conditions, such as stomach ulcers or a narrowed oesophagus.

What are the benefits of a gastroscopy?

A gastroscopy gives your doctor a direct, close-up view of the lining of your oesophagus, stomach and duodenum, which can show problems such as ulcers that aren't always visible on an X-ray or CT scan.

It also allows tissue samples to be taken and some conditions, such as bleeding or a narrowed oesophagus, to be treated during the same procedure.

Are there different types of gastroscopy?

There are two main ways of having the test, and you can usually choose between them, or discuss which is right for you with your endoscopist:

• Throat spray: A local anaesthetic spray numbs the back of your throat. You stay fully awake throughout and can go home as soon as the procedure is finished
• Sedation: Medicine given through a small tube in your arm makes you relaxed and sleepy, though not unconscious – you'll need to rest afterwards until it wears off, and someone will need to take you home.

How do I prepare for a gastroscopy?

• Stop eating at least 6 hours before the test – you can usually have small sips of water up to 2 hours beforehand
• Avoid milk in any drink for 4 hours beforehand, as this can coat the stomach lining and affect the view
• Bring a list of the medicines you take
• If you take medicines that reduce stomach acid, such as omeprazole or lansoprazole, you may be asked to stop these for about a week beforehand, unless your test is specifically to check an ulcer or monitor a condition like Barrett's oesophagus
• If you take blood thinners, such as warfarin, clopidogrel or apixaban, tell the team in advance, as you may need specific instructions
• If you have diabetes, tell the team in advance, as your usual medicine may need adjusting on the day
• If you're also having a colonoscopy on the same day, follow the separate instructions you're given for that test.

What happens during a gastroscopy?

1. A nurse asks about your health and medical history, and you change into a hospital gown
2. You speak with the endoscopist, who explains the procedure and answers any questions, and you sign a consent form
3. You choose either a local anaesthetic throat spray or sedation given through a small tube in your arm
4. You lie on your side, and a small mouthpiece is placed between your teeth to protect them and keep your mouth open
5. The thin, flexible tube is passed into your mouth, down your throat and into your stomach – you may feel like you want to be sick, but this usually stops once the tube reaches your stomach.
6. Air is passed down the tube to inflate your stomach slightly, giving a clearer view – this can make you feel bloated and you might burp a few times.
7. A tissue sample may be taken but you won't feel this happen.

The test itself is often quick, sometimes just 5 to 10 minutes, though it can take up to 45 minutes if treatment is needed. You should expect to be at the hospital for around 4 hours in total, to allow for preparation and recovery.

What happens after a gastroscopy?

You'll be moved to a recovery area. Most people feel well enough to go home within a few hours. If you had sedation, you'll need someone to take you home and stay with you for 24 hours, and you shouldn't drive, drink alcohol, operate machinery, or sign important documents during this time. If you had throat spray only, you can go home once you feel ready, though you should wait about an hour, until the numbness has worn off, before eating or drinking.

Some stomach or throat discomfort is normal and usually settles within a few hours. A sore throat can last up to 48 hours, and lozenges can help.

Feeling bloated is also common; sitting upright, walking around, warm drinks and peppermints can help you pass the trapped air.

Your doctor or nurse will usually explain what they found before you go home. If a biopsy was taken, those results take longer, and are sent to your consultant and GP.

What are the risks of a gastroscopy?

• Sore throat, bloating or mild discomfort: Common, and usually settles within a few hours to 2 days
• Reaction to sedative medication: Uncommon
• Bleeding: Uncommon, and more likely if a biopsy or polyp removal was carried out. It's usually minor and stops on its own
• Infection: Uncommon
• Perforation, a tear in the lining of your oesophagus, stomach or duodenum: Rare, about 1 in 2,500, and may need urgent treatment, a blood transfusion or an operation
• Damage to teeth, crowns or dental bridgework: A small risk.

It's also worth knowing that no test is perfect. There's a small chance that a problem could be missed, even when the gastroscopy looks normal.