Lab Test

Hydroxyindoleacetic Acid, 5 (5HIAA), Urine 24 Hour

5-HIAA, Urine 5-Hydroxyindole Acetic Acid, Hydroxyindole Acetic Acid, Urine, 5-

Test Codes



  • This test cannot be added to orders in a plain urine container without preservative.
  • Patients should avoid the following foods and medications for at least 48 hours before and during the 24 hour urine collection: bananas, walnuts, pineapple, plantain, avocados, eggplant, tomatoes, plums, kiwi fruit, chlorophenylalanine, isocarboxazid, isoniazid, levodopa, methyldopa, monoamin oxidase inhibitors (type of antidepressant), phenmetrazine, rauwolfia, or reserpine. Patients should consult their physician if they are unsure whether they are taking any of the listed medications. Patients should also consult their physician before stopping any medication.
  • A Urine Creatinine test is performed on each sample.
  • Pease refer to the Specimen Collection Manual for instructions on 24 Hour Urine Collection:

Specimen Collection Criteria

Collect: 24 hour urine sample with 15 mL of 6N Hydrochloric Acid added prior to the start of collection.

  • Keep 24 hour urine specimen iced or refrigerated during collection.
  • Include the start and end dates and times for the collection period on the specimen container.
Urine Preservative Options
No Preservative
6N Hydrochloric Acid
Boric Acid (10g)
Sodium Carbonate
50% Acetic Acid

Physician Office/Draw Specimen Preparation

Maintain specimens refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Entire 24 hour urine collection, refrigerated (2-8°C or 36-46°F).

Rejection Criteria

  • Random urine samples.
  • 24-hour urine collections will not be tested unless acid preservative is added to the collection device at the beginning of the collection period.
  • Samples not kept refrigerated (2-8°C or 36-46°F) will not be tested.

In-Lab Processing

Measure total volume of 24 hour urine specimen. Record total volume and collection start and end dates and times in the LIS system. Aliquot 25.0 mL from the well-mixed 24 hour urine collection (Minimum: 10.0 mL). The pH of the 24 hour urine collection with added preservative should be 4.0 or lower. Adjust the pH of the aliquot to between 2.0 and 3.0.


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 10 days
Refrigerated (2-8°C or 36-46°F): 14 days
Frozen (-20°C/-4°F or below): 1 year

Specimen Storage in Department Prior to Disposal:

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.


Sent to Warde Medical Laboratory, Ann Arbor, MI.


Monday, Wednesday, Friday.
Results are available in 5-7 days.

Reference Range

By report.

Test Methodology

High-Performance Liquid Chromatography (HPLC).


Elevated 5-HIAA less than 25 mg/d reflects increased serotonin production due most commonly to carcinoid tumor, where levels may exceed 350 mg/d. Dietary sources of serotonin can cause mild elevations and must be ruled out for proper interpretation.

Clinical Utility

5-hydroxyindole-3-acetic acid, a metabolite of serotonin (5-hydroxytryptamine), may be elevated in urine as a result of a metastatic carcinoid tumor (argentaffinoma), celiac sprue, tropical sprue, Whipple's disease and oat cell carcinoma of the bronchus.

CPT Codes

83497, 82570
LOINC:  1695-6


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