5-Hydroxyindole Acetic Acid, 5HIAA (Urine)

Clinical Chemistry

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Description

5-Hydroxyindolacetic acid ( 5-HIAA ) is the major serotinin metabolite that is excreted in the urine. Serotinin and 5-HIAA can be produced in excess amounts by carcinoid tumours and neuroendocrine tumours, particularly in individuals with carcinoid syndrome. Please state all drug therapy upon request. Note that several foods can falsely elevate 5-HIAA values and should be avoided for 48 hours prior to urine collection. These include most fruits ( including tomato, avocado and aubergine ) and nuts. Patient should also avoid tobacco, tea and coffee for 48 hours before and during specimen collection. Medications that can interfere in 5-HIAA measurement include paracetamol and aspirin, glyceryl guaiacolate ( an ingredient found in some cough medicines ), antihistamines, nasal drops, hypertensive medication, tricyclic antidepressants, ephedrine, diazepam, phenobarbital, heparin, methenamine, L-dopa, fluorouracil and mesalazine. Please avoid these medications for 48 hours before sampling where possible.

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Indications

Known or suspected carcinoid syndrome.

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Sample Type

24 hr urine collected in bottle containing 30 mL 2 M Sulphuric acid preservative.

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Reference Range

Reference ranges are provided on the report. Alternatively, please contact the laboratory for current ranges.

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Turnaround Time

Within 2 weeks

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Testing Frequency

Weekly

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External Notes

Please state all drug therapy upon request. Note that several foods can falsely elevate 5-HIAA values and should be avoided for 48 hours prior to urine collection. These include most fruits ( including tomato, avocado and aubergine ) and nuts. Patient should also avoid tobacco, tea and coffee for 48 hours before and during specimen collection. Medications that can interfere in 5-HIAA measurement include paracetamol and aspirin, glyceryl guaiacolate ( an ingredient found in some cough medicines ), antihistamines, nasal drops, hypertensive medication, tricyclic antidepressants, ephedrine, diazepam, phenobarbital, heparin, methenamine, L-dopa, fluorouracil and mesalazine.

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Patient Preparation

Patient should avoid eating fruits (including tomato, avocado and aubergine) and nuts for 48 hours prior to urine collection. Avoid tobacco, tea and coffee for 48 hours before and during specimen collection. Medications that can interfere in 5-HIAA measur

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Please note: the above information is subject to change and we endeavour to keep this website up to date wherever necessary.