Fasting gut hormones

Investigation Protocol


Diagnosis of patients with symptoms suggestive of a secreting neuro-endocrine tumour, and screening of patients with multiple endocrine neoplasia type 1.

Note, this test is frequently conducted with 2x24 hour urinary collections for 5 hydroxy indole amino acetic acid.


The patient needs to be fasted with nothing to eat or drink except water from midnight. They can take their medications as usual, but are asked to bring them all in with them for documentation. Histamine 2 blockers, for example ranitidine, should be stopped for 72 hours, and proton pump inhibitors, for example omeprazole, should be stopped for two weeks before this test.


Blood should be taken into a lithium heparin tube, as well as three EDTA tubes. All should immediately be centrifuged and frozen for future analysis for gut hormones. This usually includes chromogranin A and B, vasoactive intestinal peptide VIP, somatostatin, glucagon, gastrin, pancreatic polypeptide PP, and neurotensin. Blood should also be taken into a plain clotted tube for analysis of urea, electrolytes and calcium level to aid interpretation of the test.

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Patient information sheet

Fasting gut hormones 

Your doctor has asked us to coordinate a blood test to measure some very specialised hormones, which are produced in the gut. Unfortunately the samples must be taken into specially prepared bottles and then handled in a specific way after they are taken. This means that you cannot have them done at your GP surgery.

Please have water only from 11pm the night before this test. You will be offered a cup of tea or coffee and a biscuit after the samples have been taken. Unless we have given you special instructions, please take all your medication as normal on the day of this test.

You should expect your stay at the hospital to be about 15 minutes. You may bring someone to stay with you during the test but there is not enough space for more than one person. Children are discouraged, as this can be disruptive to other patients. However, if this poses a particular problem for you please discuss this with the senior nurse in the unit. 

You should be able to undertake normal activities after the test is finished and it should not interfere with your ability to drive home.

If you have any queries about the test, please contact:

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