5ohindoleacetatecsfmcnc

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

This test measures the level of 5-hydroxyindoleacetate (5-HIAA) in your cerebrospinal fluid (CSF), which is a marker of serotonin metabolism in the brain.

Quick summary

{"5-HIAA is a breakdown product of serotonin, a neurotransmitter that affects mood and behavior","This test helps diagnose conditions related to serotonin abnormalities, such as carcinoid syndrome","The sample is collected through a lumbar puncture (spinal tap)","Abnormal results may indicate neurological or psychiatric conditions","Certain foods and medications can affect test results"}

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

Key facts at a glance

LOINC: 1692-3
Short code: 5-HIAA CSF
Synonyms: 5OH-indoleacetate CSF-mCnc
Category: chemistry
Sample: csf
Container: Sterile CSF collection tube (polypropylene or glass), typically a plain red-top or sterile container
Units: N/A
Ref low: 50
Ref high: 150
Fasting: false
Population: adult
Sex: all
Age range: 0–120 years
Method: High Performance Liquid Chromatography (HPLC) with electrochemical detection or tandem mass spectrometry (LC-MS/MS)
CPT: 82163
SNOMED: 313337003
Specimen volume: 1-2 mL of CSF
Stability: Store at 2-8°C if analysis within 24 hours; for longer storage, freeze at -20°C or -80°C. Protect from light as 5-HIAA is light-sensitive.
Hemolysis max: 200
TAT: 48–168 hours
Order: routine

What is this test?

The 5-Hydroxyindoleacetate (5-HIAA) test measures the amount of 5-HIAA in your cerebrospinal fluid. 5-HIAA is the main metabolite (breakdown product) of serotonin, a chemical messenger (neurotransmitter) in the brain that plays a key role in regulating mood, sleep, appetite, and other important functions.

How is the sample collected?

The sample is collected through a procedure called lumbar puncture, also known as a spinal tap. A healthcare provider inserts a thin needle between the bones in your lower back to collect a small amount of cerebrospinal fluid. The procedure usually takes about 15-30 minutes, and you may be asked to lie flat for a short time afterward to reduce the risk of headache.

Why might I need this test?

Your doctor may order this test if they suspect conditions related to abnormal serotonin metabolism, such as carcinoid tumors (which can produce excess serotonin), certain psychiatric or neurological disorders, or to monitor treatment response in some conditions. It may also be used in research settings to study brain chemistry.

How should I prepare?

Before the test, inform your doctor about all medications you are taking, as certain drugs (including antidepressants, pain medications, and supplements) can affect serotonin levels. You may need to avoid certain foods like bananas, walnuts, and avocados for 24-48 hours before the test, as they can influence 5-HIAA levels. Your doctor will provide specific preparation instructions.

Reference range

Reference range: 50-150 ng/mL (may vary by laboratory methodology and reference population)N/A

Specimen: csf

No special preparation required. Inform patient about lumbar puncture procedure. Avoid serotonin-rich foods (bananas, walnuts, tomatoes, avocados) for 24-48 hours before collection if possible, as these may transiently affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings2

Frequently asked questions

Is the lumbar puncture procedure painful?

You may feel some discomfort or pressure during the procedure, but it is generally well-tolerated. A local anesthetic is usually used to numb the area. Some people experience a headache afterward, which can be managed with rest and adequate fluid intake.

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 or discuss them at your follow-up appointment.

What do abnormal results mean?

Abnormal 5-HIAA levels can result from various conditions. Your doctor will interpret the results in context of your overall health, symptoms, and other test findings. It does not necessarily mean you have a serious condition—further testing may be needed to determine the cause.

Are there any risks with this test?

The main risks of lumbar puncture include headache, bleeding, infection, or back discomfort. These complications are rare. Contact your healthcare provider if you experience severe headache, fever, or unusual symptoms after the procedure.

Sources

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