This site has been initiated and developed by Ipsen Ltd.
This site has been initiated and developed by Ipsen Ltd.

Blood tests

Blood samples will be collected for a range of tests. Markers for NETs that may be measured in the blood include:

  • Chromogranin A (CgA)  – this is the most important circulating tumour marker for NETs. In blood tests, the levels of CgA are higher than normal in 60% to 80% of functional and non-functional gastrointestinal NETs and pancreatic NETs.
  • Levels of other tumour markers that are released by functional and hormone-producing NETs in the blood will also be tested. These markers include hormones and peptides, such as somatostatin, pancreatic polypeptide, insulin, gastrin, glucagon, neurotensin and vaso-intestinal peptide (VIP).
  • If the results of these tests suggest the presence of NETs, imaging tests will usually be carried out.

Other blood tests for NETs may include:

  • Full blood count (FBC)
  • Kidney function tests (urea and electrolytes)
  • Liver function tests
  • Thyroid function tests
  • Pituitary hormone screen, measuring hormones such as adrenocorticotropic hormone (ACTH), prolactin, growth hormone (GH) and cortisol
  • Serum calcium and parathyroid hormone level tests, for all patients with pancreatic NETs, as a screening test for MEN-1 syndrome
  • NT proBNP– a blood test to check for carcinoid heart disease

Helen, Patient – Living with NETs

“Wait until you see your specialist or gastroenterologist before trying to understand your test results. They have the whole picture and you will be causing yourself unnecessary stress by trying to interpret your results.”

View Helen’s story >

Urine tests

5-HIAA is a 24-hour urine test that measures the amount of 5-hydroxyindoleacetic acid (5-HIAA) in the body. 5-HIAA is a substance that is broken down (metabolised) in the body from serotonin by an amino acid called tryptophan.

A high level of 5-HIAA in a 24-hour urine test sample is likely to confirm whether a person’s symptoms, such as flushing of the skin (particularly the face) and diarrhoea, are due to carcinoid syndrome. However, this test may not detect other types of tumours, such as lung NETs as they do not produce 5-HIAA. In these cases, imaging techniques may be used to identify NETs suspected of being in the lungs.

For the 5-HIAA test you will usually be asked to avoid certain foods beforehand and for 24 hours during the test as they contain substances that might artificially raise your 5-HIAA levels and so give a false positive result. These foods include chocolate, olives, bananas, pineapple and its juice; all tomato products, plums, aubergine, avocado, kiwi fruit, walnuts, brazil nuts, cashew nuts, tea, coffee and alcohol. Your NETs specialist doctor should be able to advise you on this and provide you with a list.

Catecholamines is a collective term for the hormones adrenaline, noradrenaline and dopamine. High levels of catecholamines or their metabolites in the urine or blood may indicate the presence of NETs. Catecholamines or their metabolites are usually measured in 24-hour urine samples.

Rate this content

Rating: 5.0/5. From 1 vote.
Please wait...

Find out more about NETs

Learn about NETs

Learn about NETs

Learn about carcinoid tumours, GI-NETs, pancreatic NETs and lung NETs, and the symptoms of NETs

Learn About NETs
Treating NETs

Treating NETs

Read about treatment options for NETs, including surgery, radiotherapy and medications

Treatment Options
FAQs by experts


Have a question about NETs? See if it has been answered by one of our experts

View FAQs

We use cookies to ensure that we give you the best experience on our website. Click here for more information.
This site is intended for a UK audience only. SOM-UK-003737 September 2018