Blood samples will be collected for a range of tests. Markers for NETs that may be measured in the blood include:
Other blood tests for NETs may include:
“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.”
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.
Learn about carcinoid tumours, GI-NETs, pancreatic NETs and lung NETs, and the symptoms of NETsLearn About NETs
Read about treatment options for NETs, including surgery, radiotherapy and medicationsTreatment Options
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