Skip to content

Gamma-aminobutyric acid (GABA) in plasma

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

This test measures the amount of gamma-aminobutyric acid, a key neurotransmitter in your brain that helps regulate nerve cell activity.

Quick summary

["GABA levels can help assess brain function and potential neurotransmitter imbalances."]

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

Key facts at a glance

LOINC
16887-2
Short code
GABA Amn-mCnc
Synonyms
GABA Amn-mCnc
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Is Gamma-Aminobutyric Acid (GABA)?

GABA is a chemical messenger (neurotransmitter) that plays a critical role in calming brain activity. It helps reduce excitability in nerve cells, contributing to relaxation and sleep. Low or high levels may suggest underlying neurological or psychiatric conditions.

Why Might This Test Be Ordered?

Your healthcare provider may order this test if you have symptoms like anxiety, seizures, insomnia, or other neurological concerns. It may also be used in research or specialized clinical settings to evaluate neurotransmitter function.

Specimen and Preparation

A blood sample is taken from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause discomfort. No special preparation is needed, but avoid caffeine or alcohol for 24 hours before testing if instructed.

How the Test Works

The test measures GABA concentration in your plasma using a specialized laboratory technique that detects its presence without interference from other substances.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

GABA Level

Frequently asked questions

What Does a Low or High GABA Level Mean?
While GABA levels can vary naturally, very low levels may be linked to conditions like epilepsy, anxiety disorders, or certain brain injuries. Very high levels are less common but could indicate metabolic disorders or rare genetic conditions. Results should always be interpreted by a healthcare provider in the context of your symptoms and medical history.
How Does This Test Compare to Others?
GABA testing is often used alongside other neurotransmitter tests (e.g., serotonin, dopamine) to assess broader brain chemistry. It’s not a standalone diagnostic tool but may help identify imbalances contributing to symptoms.
What Are Common Causes of Abnormal Results?
Abnormal GABA levels can result from medications (e.g., antiepileptics, antidepressants), metabolic disorders, or neurological conditions. Lifestyle factors like diet, stress, or substance use may also influence results.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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