Clinics and Departments

Laboratory Services

Lab Dept:


Test Name:


General Information

Lab Order Codes:



5-Hydroxyindoleacetic acid (5-HIAA), Urine; 5-HIAA, 24 hour Urine

CPT Codes:

83497 – Hydroxyindolacetic acid, 5-(HIAA)

Test Includes:

Urine 5-HIAA concentration reported in mg/24 hours


Test Indications:

Biochemical diagnosis and monitoring of intestinal carcinoid syndrome.

Lab Testing Sections:

Chemistry - Sendouts

Referred to:

Mayo Medical Laboratories (MML Test: HIAA/9248)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

2 – 4 days, test is set up Monday - Friday

Special Instructions:

See Patient Preparation, Collection

Submit an entire 24-hour urine collection. No preservative. Refrigerate specimen during and after collection.

Note: Starting and ending times of collection are required for a timed urine collection and must be documented electronically or on the proper request form.


Specimen Type:

Urine, timed collection


Plastic leakproof container (No preservative). Urine GUARD® collection container is preferred for a timed urine sample.

Draw Volume:

Submit an entire 24-hour urine collection

Processed Volume:

5 mL (Minimum: 3.5 mL) aliquot from a well mixed 24 hour collection


For timed urine collections, empty the bladder, discard the voided sample, and note the start time. Collect all urine voided for the specified time period. At the end of the period, note the finishing time, add the last voided sample to the container by emptying the bladder. Bring the refrigerated container to the lab. Make sure all specimens submitted to the laboratory are properly labeled with the patient’s name, medical record number and date of birth.

Special Processing:

Lab Staff:
Preferred: Add 25 mL of 50% acetic acid as preservative Use 15 mL of 50% acetic acid for children <5 years old at the end of the collection. This preservative is intended to achieve a pH of approximately between 2.0 and 4.0. Send urine specimen refrigerated. Use a 13 mL urine tube to transport. Forward promptly.

24 hour volume is required on request form for processing.

Patient Preparation:

Patient should not eat avocados, bananas, cantaloupe, eggplant, pineapple, plums, tomatoes, hickory nuts, plantain, kiwi, dates, grapefruit, honeydew, melons, nuts, pecans or walnuts for a 48 hour period prior to start of collection.

Certain medications such as L-Dopa, acetaminophen, salicylates, and cough syrup containing guarfenesin must be avoided.

Sample Rejection:

Specimen incorrectly processed; specimens other than urine; warm specimen; 24 hour volume not included on request form; unlabeled or mislabeled specimens


Reference Range:

Adults: < or = 8 mg/24 hours

Critical Values:



Intake of foodstuff with high content of serotonin within 48 hours of the urine collection could result in falsely elevated 5-HIAA excretion. See Patient Preparation

Numerous drugs affect the excretion of 5-HIAA by different mechanisms, including increased serotonin synthesis, metabolism, and release, and inhibition of uptake. See Patient Preparation.


Liquid Chromatography – Tandem Mass Spectrophotometry (LC-MS/MS)


Mayo Medical Laboratories May 2013


1/4/2011: Change in reference range. Previously listed as < or = 6 mg/24 hours.

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