- Test Name
- 5 Hydroxy Indole Acetic Acid, Urine
- Aliases
- 5-HIAA (5-Hydroxyindolacetic Acid); 5-OH-Indoleacetic Acid; Carcinoid Syndrome; HIAA (Hydroxyindoleacetic Acid);Serotonin Metabolite
- Provincial Mnemonic
- HI5U24HD
- LOINC Test Code
- 14573-0
- Description and Primary Use
- 5-Hydroxyindoleacetic acid is a metabolite of serotonin. Urinary excretion is elevated in some carcinoid tumors of the small bowel. For carcinoids, urinary 5-HIAA has a high specificity (100%) but low sensitivity (35%). Thus a normal test does not exclude carcinoid. Elevated levels are also seen less frequently with Neuroendocrine Tumours (NETs) of the lung. Typical symptoms that may lead to testing include diarrhea with episodes of flushing. Symptoms tend to be seen later in the course of the tumors and no one biomarker is considered to have adequate sensitivity or specificity to rule in or out all NETs. (See following reference for more information: Modlin IM, Neuroendocrine Tumor Biomarkers: From Monoanalytes to Transcripts and Algorithms. Best Practice & Research: Clinical Endocrinology and Metabolism 2016;30:59-77)
- Reorder interval
- Not yet defined
- TAT
- 9 Days
- Test Cost
- Tier
- 1 - General Availability
- Ordering Requirements (Restrictions / Conditions)
Enter test name (and/or Provincial Mnemonic) into Additional Requests section on the outpatient requisition form.
- Required Consultations
- Algorithms and Guidelines
N/A
- Special Patient Preparation
5 HIAA Test Preparation Instructions/Restrictions:
Diet and drug restrictions:
To be avoided for 48 hours ASA, chloralhydrate, coffee, cola drink, dopamine, erythromycin, methyldopa, niacin, phenothiazines, quinidine, quinine, riboflavin, smoking, tea, tetracycline, vitamin B.
To be avoided for 72 hours are as follows avocados, bananas, chocolate, eggplant, fruit and juice, hypertensive drugs (especially aldomet) or other drugs that affect serotonin metabolism, pineapple, plums, Tylenol (acetaminophen), walnuts.
Note: coffee, cola drinks, tea, smoking are considered drugs.
- Special Collection / Transport / Processing Requirements
24 Hour Urine Container With 25ml 6N HCL Preservative/Random Urine Acceptable.
- Criteria for Rejection
Samples maintained at ambient temperature.
- Laboratory Service Area
- Clinical Chemistry
- Performing Laboratory / Site
- Category 4 laboratory (HSC Mass Spectrometry Laboratory)
- Last Updated
- 26-Apr-19