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Test Code HIAA 5-Hydroxyindoleacetic Acid (5-HIAA), 24 Hour, Urine

Important Note

ASANTE order code: U5HIAA

Epic/Beaker code: LAB352

Performing Laboratory

Mayo Medical Laboratories in Rochester

Reporting Name

5-Hydroxyindoleacetic Acid, U

Specimen Type


Necessary Information

24-hour volume is required.

Specimen Required

Patient Preparation:

1. Some medications (see below) could interfere with test results. The ordering provider should decide if any medications should be stopped and when they should be restarted.

2. For 48 hours before patients start their urine collection and during the 24 hours they collect urine:

Limit the following to 1 serving per day:




-Caffeinated beverages or foods


If clinically feasible, discontinue the following medications at least 48 hours before specimen collection:

-Acetaminophen (Tylenol or generic versions)



-Cough syrups

-Cold and flu medications

Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL urine tube (T068)

Specimen Volume: 5 mL

Collection Instructions:

1. Collect a 24-hour urine specimen.

2. Add 25 mL of 50% acetic acid as preservative at start of collection. Use 15 mL of 50% acetic acid for children <5 years old.

Additional Information: See Urine Preservatives-Collection and Transportation for 24-Hour Urine Specimens in Special Instructions for multiple collections.

Reject Due To









Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 56 days
  Frozen  365 days

Specimen Minimum Volume

1 mL

Day(s) and Time(s) Performed

Monday through Thursday; 11 a.m.

Friday; 2 p.m.

Specimen Retention Time

7 days

Analytic Time

2 days (not reported on Saturday or Sunday)

Reference Values

≤8 mg/24 hours


For SI unit Reference Values, see

Useful For

Biochemical diagnosis and monitoring of intestinal carcinoid syndrome

Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
HIAA 5-Hydroxyindoleacetic Acid, U In Process


Result ID Test Result Name Result LOINC Value
9248 5-Hydroxyindoleacetic Acid, U 1695-6
TM35 Collection Duration 13362-9
VL33 Urine Volume 3167-4

Clinical Information

5-Hydroxyindoleacetic acid (5-HIAA) is the major metabolite of serotonin and is excreted in the urine. Intestinal carcinoid tumors along with neuroendocrine tumors can produce excess amounts of 5-HIAA and serotonin especially in individuals with carcinoid syndrome. Carcinoid syndrome is characterized by carcinoid tumors, flushing, heart disease, and hepatomegaly.


Measurement of 5-HIAA in a 24-hour urine specimen can diagnose carcinoid disease with a high specificity.


Elevated excretion of 5-hydroxyindoleacetic acid is a probable indicator of the presence of a serotonin-producing tumor, if pharmacological and dietary artifacts have been ruled out.


Intake of food with a high content of serotonin (avocados, dates, eggplant, all fruit [including bananas, cantaloupe, grapefruit, kiwifruit, melons, pineapple, plantains, plums], all nuts [including hickory nuts, butternuts, pecans, walnuts], and tomatoes and tomato products) within 48 hours of the urine collection could result in falsely elevated 5-hydroxyindoleacetic acid (5-HIAA) excretion.


Numerous drugs affect the excretion of 5-HIAA by different mechanisms, including increased serotonin synthesis, metabolism, and release and inhibition of uptake. The following medications can interfere with 5-HIAA results. If clinically feasible, discontinue the following medications at least 48 hours before specimen collection.

-Acetaminophen (Tylenol or generic versions)



-Cough syrups

-Cold and flu medications


Patient should also avoid caffeinated beverages such as tea and coffee or caffeinated foods for 48 hours before and during specimen collection.

Clinical Reference

1. de Herder W: Biochemistry of neuroendocrine tumours. Best Pract Res Clin Endocrinol Metab 2007 Mar;21(1):33-41

2. Manini P, Andreoli R, Cavazzini S, et al: Liquid chromatography-electrospray tandem mass spectrometry of acidic monoamine metabolites. J Chromatogr B Biomed Sci Appl 2000 July 21;744(2):423-431

3. Mashige F, Matsushima Y, Kanazawa H, et al: Acidic catecholamine metabolites and 5-hydroxyindoleacetic acid in urine: the influence of diet. Ann Clin Biochem 1996;33:43-49

4. Vinik A, Feliberti E, Perry RR: Carcinoid Tumors. In: Endotext. Edited by LJ De Groot, P Beck-Peccoz, G Chrousos. South Dartmouth, MA, Inc; 2000. Available at

5. Serotonin syndrome. In POISINDEX System. Edited by RK Klasco, CR Gelman, LT Hill. Greenwood Village, Colorado, Micromedex, 2002

Method Description

5-Hydroxyindoleacetic acid (5-HIAA) is measured by solid phase extraction (SPE) of an aliquot from a 24-hour urine collection and liquid chromatography/tandem mass spectrometry analysis. 5-HIAA is quantitated using a custom synthesized stable isotope labeled internal standard (d6-5-HIAA) from calibration over a concentration range 0.5 to 150 mg/L.(Kroll CA, Magera MJ, Helgeson JK, et al: A liquid chromatography-tandem mass spectrometry method for the determination of 5-hydroxyindole-3-acetic acid in urine. Clin Chem 2002;48:2049-2051)

Urine Preservative Collection Options







6N HCl

Yes (30 mL)

50% Acetic Acid

Preferred (25 mL)


Yes (5 g)


Yes (30 mL)


Yes (15 mL)

Boric Acid

Yes (10 g)

Thymol (10% in isopropanol)

Yes (10 mL)



If not ordering electronically, complete, print, and send an Oncology Test Request Form (T729) with the specimen (