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Tests for carcinoid tumour of the bowel and stomach

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This page tells you about the tests you might have for carcinoid (neuroendocrine tumour) of the bowel or stomach. You can find the following information


A quick guide to what's on this page

Blood and urine tests

Carcinoid tumours can make hormones and other substances that show up in your blood or urine. You will have blood and urine tests to look for these.


You may have scans including a CT scan, MRI scan, PET-CT scan, an ultrasound scan or a radioactive scan. These are all different ways of showing up any possible tumours.

Endoscopy and colonoscopy

For an endoscopy, a doctor or specialist nurse passes a flexible tube down your throat to look inside your food pipe (oesophagus), stomach and first part of your small bowel (duodenum). For a colonoscopy, they pass a tube into your back passage to examine your bowel. For these tests you may have a sedative to make you drowsy. 

You may have a capsule endoscopy which can take pictures further along the small bowel.

Barium tests

Barium can coat the inside of organs and help them show up clearly on X-ray scans. You can have it as a drink or as an enema, depending on the part of the digestive system the doctors are checking.


If your tests show an abnormality you may need to have a biopsy. The doctor takes a small sample of tissue from the affected area. It is looked at under a microscope by a pathologist. Your doctor may take a biopsy during another test, such as an endoscopy, or you may have a small operation to remove the tissue sample.


CR PDF Icon You can view and print the quick guides for all the pages in the diagnosing carcinoid section.



Blood tests

Some carcinoids make hormones and these can cause the symptoms of carcinoid syndrome. Blood tests can help to show if your carcinoid is making hormones. 

Your tests will include one to measure the amount of serotonin in the blood and one to measure the amount of a protein called chromogranin A (CgA). Chromogranin A levels in blood need to be checked at specialist laboratories and so the result takes at least a week.


Urine tests

Carcinoid tumours – especially carcinoids of the small bowel – sometimes release high amounts of serotonin. The body breaks down serotonin to a substance called 5-HIAA. We get rid of 5-HIAA in our urine, so a raised amount in the urine can be a sign of carcinoid. 

Your doctor will ask you to collect all your urine over 24 hours to measure the amount of 5-HIAA. 

While you are collecting urine for this test, and for a few days before, you should avoid eating foods which are rich in serotonin, such as bananas, tomatoes, avocados, walnuts, pineapple and kiwi fruit.

Some medicines can also affect the level of 5-HIAA in your urine. So you may need to stop taking them for a few days before your test. Your doctor or nurse will advise you about this.


CT scan

A CT scanner takes X-rays from different angles to form a detailed image of the inside of your body. The doctor uses the scan to see if there is a tumour, how big it is and whether it has spread anywhere else.

About an hour before the scan, you drink a liquid that helps to make the scan clearer. They may ask you not to eat or drink for several hours beforehand. You have more of the special liquid while in the X-ray department. Or if your scan is of the lower part of your bowel, the doctor or radiographer may put the liquid into your back passage (rectum) just before the scan. 

You may have a small thin tube called a cannula put into one of your veins in your arm. This is so that they can inject dye into your blood vessels during the scan. This can give more detailed pictures of some organs.

Read more about having a CT scan.


MRI scan

An MRI scanner uses magnetism rather than X-rays to build up a picture. MRI scans are especially good at showing up soft tissue in the body. 

For this scan you need to change into a gown and remove jewellery and other metal objects. During the scan you need to lie very still. You may find the test very noisy. You will have earplugs or headphones to help block out the noise. 

Read about having an MRI scan.


PET-CT scan

A PET-CT scan combines a CT scan with a PET scan to give detailed information about a tumour and whether it has spread. 

A PET scan uses a mildly radioactive drug to show up areas of the body where cells are more active than normal. 

Read more about having a PET-CT scan.



An endoscopy looks at the inside of your digestive system. You may have medicines (sedatives) to make you drowsy for this test.

A doctor or specialist nurse uses a long flexible tube (endoscope) with a tiny camera and light on the end to look inside your food pipe (oesophagus), stomach and part of the small bowel (duodenum). They may take a biopsy of any abnormal areas at the same time.

Read more about having an endoscopy.


Endoscopic ultrasound (EUS)

An endoscopic ultrasound (EUS) is the same as having an endoscopy. But the endoscopy tube takes pictures using ultrasound. 

By doing the ultrasound at the same time, your doctor can see the inside of your oesophagus and stomach. They can also see ultrasound pictures of the outer layers of the gut and the area around it. They may also take a biopsy during the EUS.



A colonoscopy is a type of endoscopy that looks at the inside of the large bowel.

A doctor or specialist nurse uses a flexible tube with a light and small camera at one end. They gently pass it into your back passage (rectum) and up into your bowel. They take pictures of your bowel, and biopsy any abnormal areas.

Read more about having a colonoscopy.


Capsule endoscoopy

Capsule endoscopy is a way of looking at the parts of the bowel which cannot be reached by a normal endoscopy or colonoscopy.

You swallow a small camera in the form of a pill. This takes lots of photographs on its way through your gut. These pictures are transmitted to a data recorder that your wear around your waist for about 8 hours. The pictures are then downloaded to a computer. The capsule is disposable and you pass it naturally in your stools (poo).

Read about having a capsule endoscopy.


Barium tests

Doctors can use barium to coat the inside of organs and help them show up clearly on X-ray scans. You can have barium as a drink or as an enema, depending on the part of the digestive system the doctors are checking. 

You have it as a drink for a barium meal or barium swallow. A barium swallow looks at the food pipe (oesophagus) and a barium meal looks at the stomach and small bowel. The doctor or radiographer takes a series of X-rays as the barium passes down through your throat and into your stomach. 

Read about having a barium swallow.

To have a barium enema, the doctor or radiographer runs a mixture of white liquid barium and water into your bowel through a tube and takes a series of X-ray pictures of your bowel. The barium helps any lumps or swelling show up in the pictures.

Read more about having a barium enema.



If your tests show an abnormality your doctor may want you to have a biopsy. They take a small sample of tissue from the abnormal area. Your doctor may do this when you have a colonoscopy, endoscopy or endoscopic ultrasound (EUS). 

If it isn’t possible to take a biopsy during one of these tests, your doctor may take the tissue sample during a small operation. You will need to have a general anaesthetic for this.

The sample of tissue is looked at in a laboratory by a specialist pathologist. The results takes at least a week.


Radioactive scans – octreoscan or MIBG

Octreotide and MIBG are substances that some carcinoid cells can take up (absorb). Doctors can attach a radioactive substance to octreotide or MIBG, which then shows up on scans. They are called an octreoscan (or somatostatin receptor scintigraphy) or MIBG scan. 

The scans show up areas where radioactivity has collected in the body. This can show where a carcinoid tumour is and whether it has spread. 

The radiographer or technician gives you the radioactive substance into a vein in your arm. About 4 hours later, you lie on the scanning bed to have a scan of your whole body. You have another scan the next day, and possibly the day after that. 

The dose of radiation for these tests is low. But after having the radioactive injection and for a couple of days afterwards, you should avoid long periods of close contact with pregnant women and children. The staff at the hospital will give you advice about this.


Tests to check your heart

If you have carcinoid syndrome or a carcinoid in your small bowel you have a higher risk of heart disease. You will have an echocardiogram at diagnosis and continue to have regular check ups. 

If you have any changes in your heart, you will see a doctor who specialises in heart problems. You may need to take tablets to help. Some people may need to have surgery to the heart valves.

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Updated: 24 May 2016