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Urine 5-HIAA (24 hour)

Adrenal, pituitary and other hormones · also printed as 5-HIAA, 5 HIAA, 5-hydroxyindoleacetic acid, Urinary 5-HIAA, 24h urine 5-HIAA

Typical UK adult rangebelow 42 umol/24h

Ranges vary between laboratories; the range printed on the report takes precedence.

What this test measures

5-HIAA is the breakdown product of serotonin. A day's urine is measured to screen for carcinoid tumours, rare gut tumours that release serotonin.

Why doctors request it

Requested for flushing and diarrhoea when a carcinoid tumour is being considered.

What commonly pushes it up

A carcinoid (neuroendocrine) tumour
Foods rich in serotonin eaten in the previous three days: bananas, pineapple, kiwi, walnuts, tomatoes, aubergine
Some medicines as a class, for example paracetamol and some cough medicines

What commonly pushes it down

Some medicines as a class, for example aspirin and some antidepressants

Everyday reasons for a value outside the range

Diet in the three days before collection is the commonest reason for a raised value

About the sample

Avoid the listed foods for three days; every drop for exactly 24 hours.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

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This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.