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5HIAA
(a.k.a 5-hydroxyindoleacetic acid, serotonin metabolites)
24 Hour Urine (acid Preservative)(Phone (82)4712 to order)
Test Code: 5HI
Tube type: Acid 24hr Urine
Special instructions
An initial screen can be performed without dietary restriction, but if results are equivocal or high then certain foodstuffs including bananas, tomatoes, chocolate, plums, pineapples, kiwi, avocados, aubergines, plantain and walnuts should be avoided for 48 hours prior to and during a repeat collection, as they are rich in precursors of 5-HIAA.
There are also certain cough medicine that contain serotonin that can affect the 5HIAA test. Other medications may also cause changes in 5-HIAA metabolism (e.g. SSRIs): please state current medications, including OTC, on the request form.
Ideally the sample collection should coincide with an episode of symptoms (flushing or diarrhoea).
Samples contaminated with blood or faeces cannot be assayed - in these circumstances please discard and request a fresh collection container.
Sent away
to Bristol Royal Infirmary
Reference range
<4.0
Units
mmol/mol (5HIAA/Creatinine)
Turnaround Time
28
days
Department: Biochemistry
Clinical Application
5-hydroxyindole acetic acid (5-HIAA) is the major metabolite of serotonin which can be produced in excess by carcinoid tumours. Symptoms of carcinoid syndrome include flushing, hepatomegaly, diarrhoea, bronchospasms and heart disease.
There is, however, a poor correlation between urinary 5-HIAA levels and the clinical severity of carcinoid syndrome. Chromogranin A may be useful in patients with normal renal function.
Webpage updated: June 2024
Links:
» Patient Instructions for 5HIAA Acidified 24hr Urine Collection
