Capsule Sponge Test
Information for patients with persistent acid reflux, heartburn, or known Barrett's Oesophagus
This leaflet provides you with information about the capsule sponge test (CST). It explains the following.
What a capsule sponge test is.
Why we have offered you a CST instead of an upper endoscopy.
What the purpose of this test is.
What the benefits are to having a CST instead of an upper endoscopy.
What happens next:
Pre-assessment appointment
The day of your test
At the hospital
What happens during your test.
What happens after your appointment.
How will you get your results.
Any possible side effects.
What the consent form is.
Who to contact with any questions or concerns.
We hope this leaflet answers some of the questions you may have. If you have any further questions or concerns, please speak to the Alternative Pathways Unit.
What is CST?
A capsule sponge test (CST) is a small capsule on a string. The capsule is a similar size to a vitamin tablet, and is made from vegan gelatine.
The capsule contains a small sponge. During the test, the sponge collects a sample of cells from your oesophagus (food pipe). After the test, the cells are tested to find out if any are unexpected or abnormal.
Why have I been offered CST instead of an upper endoscopy?
We have referred you for this test as you have acid reflux, heartburn, or Barrett’s Oesophagus.
The test can help provide a diagnosis without having a more intrusive test. The alternative is an upper endoscopy procedure. This involves inserting a long, flexible tube called an endoscope, down the throat and into the oesophagus or food pipe.
It is your decision whether to have this test, or whether you want to go straight to upper endoscopy.
What is the purpose of this test?
Many people have heartburn and acid reflux. These conditions can usually be treated with medication and lifestyle changes. For example:
not eating heavy meals late at night; or
not eating food which may increase heartburn (such as fizzy drinks, and acidic or spicy foods).
Some people with regular heartburn develop a condition called Barrett’s Oesophagus. This is when cells in the food pipe (oesophagus) change shape. About 3 to 6 people in every 100 with regular heartburn develop Barrett’s Oesophagus.
People with Barrett’s Oesophagus have a slightly higher chance of developing oesophageal cancer. If we find cancer early, a patient's outcomes are improved.
If you need more information on Barrett’s Oesophagus, please speak to your nurse.
What are the benefits to having a CST instead of an upper endoscopy?
Like an upper endoscopy, we use a CST to diagnose abnormalities in your oesophagus. The results of both tests will show us what treatment you need.
CST is a much quicker test than an upper endoscopy, and less invasive.
You will not need sedation or throat spray to numb your throat.
As you do not need sedation, you can eat and drink as normal once your test is complete.
The test takes less than 10 minutes to complete.
A nurse carries out the test in a clinic room. There is no need to change into a hospital gown.
You can return to work and drive straight after your procedure.
What happens next?
The CST comes in two parts, on separate days.
Pre-assessment appointment
Your pre-assessment appointment will last up to 30 minutes and will take place over the phone.
Please let the nurse know if you have any questions or worries about your CST.
Please have a list of all your prescribed medications ready for this appointment.
If you have diabetes, please tell the nurse so they can arrange the most suitable appointment for you. We can also discuss with you any worries you may have about being nil by mouth for 6 hours.
If you take Mounjaro or other GLP-1 agonists weekly injections, stop taking these one week before your appointment. You will need to be on a liquid diet for 24 hours before your procedure.
Please let the nurse know if you have any existing medical conditions.
The day of your test
You must not eat or drink (including water) for 6 hours before your appointment time.
Take your medication as normal, but only with a sip of water.
Please bring a list of your prescribed medications with you to your appointment.
Remember to bring your unsigned consent form, as explained at the end of this leaflet.
We are happy for someone to come to the hospital with you. However, they cannot come into the clinic room with you, unless there are exceptional circumstances. If you have any concerns about this, please speak to the nurse at your pre-assessment appointment.
At the hospital
Please arrive on time for your appointment.
Please refer to your appointment letter for information on when and where your test will take place.
For appointments at Buckland Hospital, Dover. Please report to Outpatients, by the main entrance. The receptionist will let the nurse know of your arrival.
For appointments at Queen Elizabeth the Queen Mother (QEQM) Hospital, Margate. Please report to the Endoscopy Unit in the St Peter’s Road hospital entrance.
For appointments at William Harvey Hospital, Ashford. Please report to the Endoscopy Unit in the Pink Zone. The nearest hospital entrance is the Arundel Unit door.
Your appointment will last approximately 30 minutes.
What happens during my test?
At your appointment, a nurse will go through the test with you, and answer any questions you may have. The nurse will ask you to sign a consent form agreeing to the test.
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The nurse uses an applicator to place the capsule on the back of your tongue. The nurse will give you warm water to drink, and ask you to swallow the capsule. You may feel the string in your mouth to begin with, but that feeling usually goes away. -
After swallowing, the capsule will stay in your stomach for 7 minutes until it dissolves. Once it has dissolved, a small soft sponge is released. During this time, you stay in the room with the nurse performing the procedure. Please bring something to do to distract you, such as a book or phone. -
The nurse will gently remove the sponge by pulling on the thread. This will only take 1 or 2 seconds. It should not be painful, but you may feel like the inside of your gullet is being brushed. As the sponge is pulled out, it collects a sample of the cells lining your oesophagus (food pipe). Although this is a quick process, it may cause you to gag.
What happens after my appointment?
After your test, you can leave hospital and carry on with your day as normal - eating, drinking, and going back to work.
You may have a mild sore throat after your test. Drinking any type of fluid frequently or sucking throat lozenges can help.
It is very unlikely you will have any other symptoms. However, please contact the Alternative Pathways Unit if you have any concerns, or severe pain or bleeding. Please see Are there possible side effects? for more information. The unit's contact details are at the end of this leaflet.
Outside normal clinic hours, please go to the Emergency Department. Tell them you have had a CST.
If your heartburn symptoms become worse, continue to take your heartburn medication and contact your GP.
We will send your cell sample to a laboratory. The sample will be tested for signs of Barrett’s Oesophagus, inflammation, or cancerous changes.
How will I get my results?
The results of your test will take around 2 to 3 weeks. A nurse will contact you with your results. Your GP and referring consultant will be sent a copy of your results.
If your CST test shows your cells are normal
If you have this result you will receive a letter in the post. It means that there is no evidence of damage to your oesophagus (food pipe). You will continue with your current treatment (such as acid-suppressants) for your symptoms.
If the CST tests finds any abnormal cells or is inconclusive
You will need further investigation of your oesophagus (food pipe). This is usually an upper endoscopy. You will receive a phone call from the nurse to discuss the reasons for this. If you need more information on this investigation, please speak to your nurse.
Are there possible side effects?
Over 10,000 people in the UK have had a capsule sponge test so far, with no serious side effects.
Swallowing the capsule is not painful. Most people have no problem doing so. If you do have a problem, we will not continue with the test. We will tell the Endoscopy Unit that you are not suitable for CST and will need an upper endoscopy instead.
You may have a mild sore throat after your test, which can last for up to 48 hours. This is easily treated with fluids and / or lozenges.
There is a small risk (less than 1 in 5,000) that:
the string may become detached from the sponge; or
it may be difficult to remove the sponge.
If this happens, it is not painful or dangerous. You will have an upper endoscopy to remove the sponge within 4 to 6 hours.
There is a very small possibility that the capsule could go into your lungs instead of your stomach. To date this has not happened.
The device may damage to the lining of your oesophagus. If this happens, there is a very small chance that your oesophagus could become infected and need treatment. To date this has not happened.
Oesophageal spasm is a condition where the oesophagus (food pipe) becomes confused. The oesophagus is designed for items to go down not up, so it can go into spasm. If this happens, we will sit you quietly and treat your symptoms.
You may have some streaking of red blood when you cough or vomit after your procedure. This is caused by irritation from the device. If this happens, it should last no more than 24 hours.
Contact the Alternative Pathways Unit, using the contact details at the end of this leaflet, if:
the amount of red blood is a lot more; or
you notice red stools (poo) when you go to the toilet.
Outside normal clinic hours, please go to the Emergency Department. Tell them you have had a CST.
Like all tests, the CST may not find all abnormalities. On very rare occasions, the test may not find a serious abnormality. If you have any questions about this, please speak to the nurse at your pre-assessment or procedure appointment.
What is the consent form?
When you come to your appointment, bring the unsigned consent form with you. If you decide to go ahead with the CST, we will ask you to sign the form. This confirms that you agree to have the test and that you understand what it involves. You must make sure you have read and understood all the information we have given you.
If you decide not to have the procedure, you can withdraw your consent for treatment at any time.
Contact details
If you have any questions, please contact the Alternative Pathways Unit between 8am and 6pm, Monday to Friday.
Alternative Pathways Unit
Telephone: 01304 222558
Ask 3 Questions
There may be choices to make about your healthcare. Before making any decisions, make sure you get the answers to these three questions:
What are my choices?
What is good and bad about each choice?
How do I get support to help me make a decision that is right for me?
Your healthcare team needs you to tell them what is important to you. It’s all about shared decision making.
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