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

Reporting Name

5-Hydroxyindoleacetic Acid, U

Useful For

Biochemical diagnosis and monitoring of intestinal carcinoid syndrome

Method Name

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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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.

Specimen Minimum Volume

1 mL

Specimen Stability Information

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

Reference Values

≤8 mg/24 hours


For SI unit Reference Values, see

Day(s) and Time(s) Performed

Monday through Thursday; 11 a.m.

Friday; 2 p.m.

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 1695-6


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

Urine Preservative Collection Options

Note: The addition of preservative or application of temperature controls must occur within 4 hours of completion of the collection.







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)