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5ohindoleacetate24hurmcnc

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of 5-HIA in a 24-hour urine sample to help diagnose carcinoid tumors.

Quick summary

{"Measures serotonin breakdown product in urine","Used to screen for carcinoid tumors (neuroendocrine tumors)","Requires 24-hour urine collection","Results help doctors monitor treatment effectiveness","Certain foods and medications can affect results"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
31203-3
Short code
5HIAA
Synonyms
5OH-indoleacetate 24h Ur-mCnc
Category
chemistry
Sample
urine
Container
Brown or opaque 24-hour urine collection container with preservative (typically 10% HCl or acetic acid)
Units
N/A
Ref low
2
Ref high
9
Critical range
— – 50 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
High Performance Liquid Chromatography (HPLC) with electrochemical detection or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
CPT
83456
SNOMED
271295003
Specimen volume
Minimum 10 mL from well-mixed 24-hour collection, record total collection volume
Stability
Room temperature: 24-48 hours; Refrigerated (2-8°C): 5-7 days; Frozen (-20°C): 2-3 weeks. Protect from light.
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
48–72 hours
Order
routine

What is this test?

The 5-Hydroxyindoleacetate (5-HIA) test measures the level of 5-HIA in your urine. 5-HIA is a breakdown product of serotonin, a hormone produced by certain cells in your body. This test is primarily used to detect and monitor carcinoid tumors, which are rare neuroendocrine tumors that can develop in various parts of the body, commonly in the digestive tract or lungs.

How is the test performed?

For this test, you will need to collect all urine produced over a 24-hour period. Your healthcare provider will give you a special container for collection. During the collection period, keep the container refrigerated or in a cool place. Make sure to label the container with your name, date, and time of collection. After 24 hours, return the container to your laboratory or healthcare provider as instructed.

How to prepare for the test?

Before the test, inform your doctor about all medications you are taking, as certain drugs can affect the results. You may need to avoid certain foods for 2-3 days before the test, including bananas, avocados, tomatoes, walnuts, and pineapple, as these contain substances that can influence serotonin levels. Also avoid alcohol, caffeine, and tobacco during the collection period. Follow any specific instructions provided by your healthcare team.

Reference range

2.0 - 9.0 mg/24 hours (or 10.5 - 47.5 μmol/24 hours)N/A

Specimen: urine

Patient should avoid serotonin-rich foods for 48-72 hours before and during collection including: bananas, avocados, walnuts, pecans, pineapples, tomatoes, kiwi fruit, plums, and eggplant. Avoid medications that may interfere including: acetaminophen, aspirin, caffeine, cough syrups, nicotine, and MAO inhibitors. Specific serotonin reuptake inhibitors (SSRIs) should be discussed with prescribing physician as they may affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Frequently asked questions

Does the test hurt?
No, this is a non-invasive test. You simply collect urine normally over 24 hours. There is no pain involved.
How long does it take to get results?
Results are typically available within a few days to a week, depending on the laboratory. Your healthcare provider will contact you with the results.
What do abnormal results mean?
Elevated 5-HIA levels suggest the possibility of a carcinoid tumor or carcinoid syndrome. However, further testing and imaging studies are usually needed to confirm the diagnosis and locate the tumor. Your doctor will explain the results and recommend next steps.
Can I collect urine while at work or traveling?
Yes, you can collect urine while going about your normal activities. Keep the collection container cool (such as in a cooler with ice) and carry it with you. Make sure to label it clearly and follow the same instructions as at home.
  1. 1
    MedlinePlus - Carcinoid TumorSource
  2. 2
    National Cancer Institute - Neuroendocrine TumorsSource
  3. 3
    Mayo Clinic Laboratories - 5-HIAA, UrineSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy