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Blood Sciences

Blood Test Information

5HIAA
(a.k.a 5-hydroxyindoleacetic acid, serotonin metabolites)
24 Hour Urine (acid Preservative)(Phone (82)4712 to order)

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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 3 days 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 Sheffield Northern General Hospital

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: September 2024

Links:
» Patient Instructions for 5HIAA Acidified 24hr Urine Collection

 
 

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