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Clinical Biochemistry

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5-Hydroxyindoleacetic acid (Urine)

Also known as: 5-HIAA, HIAA, Serotonin metabolite

Specimen requirements

Sample type: Urine (24 hour acetic acid bottle); Urine (Universal)

Collection requirements: Specimen must be protected from light, processed and frozen on day of receipt. Random urine specimen must be protected from light.

Serotonin-rich foods, such as:

  • avocados
  • bananas
  • plantains
  • pineapples
  • plums
  • walnuts
  • tomatoes
  • kiwi fruit
  • health food supplements containing 5-hydroxytrytophan

can increase 5-HIAA, and should be avoided for three days prior to and during urine collection.

A variety of medications can affect 5-HIAA excretion - for more information please contact us.


Price on application

Turnaround time

Please see Turnaround times

Analytical method

Mass Spectrometry

Analysis undertaken at these site(s)

John Radcliffe Hospital

Reference intervals


All ages: 10 - 40 µmol/24 hours

<5 µmol / mmol creatinine


All ages: 10 - 40 µmol/24 hours

<5 µmol / mmol creatinine

Last reviewed:12 June 2023