Colon capsule endoscopy

A colon capsule endoscopy looks at the inside of your large bowel (colon). You might have it if you have symptoms of bowel cancer.

You swallow a capsule that contains a small disposable camera. The capsule is the size of a large vitamin pill. The camera takes thousands of pictures as it travels along your gut. The camera transmits the pictures wirelessly to a data recorder that you wear on your waist.

The test is complete once the capsule has passed through your bowel and out into the toilet. A doctor or specialist nurse looks at the pictures from the data recorder to help find out the cause of your symptoms.

This test isn’t available in all hospitals at the moment.

The information on this page is about a capsule endoscopy for the large bowel. For information about a capsule endoscopy for small bowel follow the below link.

Diagram showing a colon capsule endoscopy

Why you might have a colon capsule endoscopy

You might have a colon capsule endoscopy if you have symptoms of bowel cancer. This includes having blood picked up in your poo on a Faecal Immunochemical Test (FIT).

Usually if you have symptoms of bowel cancer you have a colonoscopy. For this test, your doctor puts a tube with a camera on the end into your back passage to look inside your large bowel (colon). In March 2021, NHS England announced that some people with symptoms of bowel cancer may have colon capsule endoscopy instead of having a colonoscopy straight away.

The colon capsule endoscopy can help to rule out bowel cancer. And many people do not need to have further tests. The colon capsule endoscopy is a less invasive test than colonoscopy, which people may prefer.

You still need to have a colonoscopy if your doctor sees any abnormal areas on the colon capsule endoscopy. This is so they can take samples of tissue (biopsies) or remove growths (polyps) if necessary.

Colon capsule endoscopy is a new project that is taking place in a number of hospitals across England. They may offer you this test if it’s available in your area.

Some hospitals in Scotland started to use colon capsule endoscopy towards the end of 2020. It will become available in more hospitals over the coming months.

Preparing for your colon capsule endoscopy

Before the test, you must stop eating for some time. Your appointment letter will have instructions on what to do and what you can eat and drink.

You normally have a low fibre diet for about 5 days before your test. You also need to take some medicine to empty your bowels (laxatives). They call this bowel preparation or bowel prep. It’s important to follow the instructions carefully so that you have a clean bowel for the test.

You take your usual medicines as normal in the days leading up to the test. Your nurse will ask you to stop taking the following medicines one week before the test:

  • iron tablets
  • non steroidal anti inflammatory drugs (such as ibuprofen, diclofenac or celecoxib)

Your nurse will tell you when to take your regular medication on the day of the test. Contact them about this if you have any questions. 

Instructions vary slightly between hospitals but the following is generally what happens. 

The day before the test:

  • Don't eat anything after lunch.
  • Drink only clear fluids for the rest of the day - this includes black tea and black coffee.
  • Start taking the bowel preparation as your appointment letter describes – it usually is a powder that you dissolve in water and drink over a set time, such as an hour or two.

On the day of the test:

  • Take the remaining bowel prep in the morning.
  • Do not eat anything until your appointment. You can only drink water.
You can’t have this test if you are pregnant. Phone the hospital before your appointment if you are pregnant or think you might be. Also contact the hospital if you have a pacemaker, an artificial heart valve, cochlear implant or an internal electromedical device.

What happens during the colon capsule endoscopy?

At the hospital

You go to the outpatient department or the endoscopy unit on the morning of the test. You are at the hospital for about an hour. The test itself can take up to 10 hours.

In some hospitals, they may offer you to have the test at home. This means you won’t need to go into hospital at all. A courier will deliver the capsule, data recorder and laxatives to you, with all the instructions. They pick the recorder up the next day and return it to the hospital.

The doctor or nurse will explain the procedure to you and ask you to sign a consent form. This is a good time to ask any questions you may have. 

There are two ways you may have the test.

The most common way is to wear a belt with built in sensors inside it.

Photograph showing a capsule endoscopy

Or the nurse or technician may put some sticky pads (sensors) on your chest and stomach area. They then attach a data recorder to a belt that you wear around your waist. Make sure you don't use any body lotion or sprays to these areas.

Diagram showing sensors and data recorder - capsule endoscopy

Once this is in place, your nurse, doctor or technician will ask you to swallow a capsule which has the camera inside. You swallow it whole with some water.

Your nurse tells you when you can drink again and when you can have a light snack.

During the test you should avoid physical exercise that makes you sweaty, and also avoid bending or stooping.

At home

Once you have swallowed the capsule and your nurse has given you all the instructions, you can leave the hospital.

They will give you instructions about taking more laxatives for your bowel. This is to keep your bowel moving which helps the capsule pass through before the battery life ends.

To help keep your bowel moving, it’s also important to stay active during the test. When you sit or lie down, your bowel movement slows down.

You may go back to hospital later that afternoon to check if the capsule has passed into the large bowel. 

The camera takes pictures as it passes through your bowel. It sends all the photos that it takes to the data recorder. You need to check the blue light is flashing on the data recorder.

Your nurse will tell you when you can start to eat and drink normally again. This is usually about 8 hours after you swallowed the capsule. You can remove the sensors or belt once the test has finished. You return the data recorder to the department later that day or the next day. 

After your colon capsule endoscopy

A technician downloads the pictures from the data recorder to a computer. A doctor or specialist nurse then looks at the pictures.

The capsule is disposable. You pass it naturally in your poo when you go to the toilet.

You must not have an MRI scan until after you have passed the capsule out of your body.

Possible risks

The team caring for you will give you phone numbers to contact if you have any questions or problems after your test. 

A capsule endoscopy is usually a very safe procedure. Your doctors make sure the benefits of having a capsule endoscopy outweigh any possible risks.

Very rarely, the capsule might get stuck inside your body. Tell your doctor or nurse if you are worried that you have not passed out the capsule. You might need an x-ray to check if it is still in your bowel.

If you develop tummy pain, vomiting or generally feel unwell, follow the advice your team gave you and contact them.

Getting your results

It may take some days or weeks for the medical team to look at all the pictures. They send the results to the doctor who arranged the test. 

Waiting for results can make you anxious. You might have contact details for a specialist nurse who you can speak to for information and support if you need to. It may help to talk to a close friend or relative about how you feel.

For information and support you can contact the Cancer Research UK nurses on freephone 0808 800 4040. The lines are open from 9am to 5pm, Monday to Friday.

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