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Gamma-Glutamyl Transferase (GGT) in Serum

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

This test measures the activity of an enzyme called gamma-glutamyl transferase, which helps assess liver function and detect potential liver damage or disease.

Quick summary

["GGT can help identify liver issues, including alcohol-related damage or other conditions affecting bile flow."]

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

Key facts at a glance

LOINC
31398-1
Short code
GD1a Gangl IgM CSF-aCnc
Synonyms
GD1a Gangl IgM CSF-aCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Matters

Gamma-glutamyl transferase (GGT) is an enzyme found in the liver, bile ducts, and other organs. When liver cells are damaged, this enzyme leaks into the bloodstream, raising its levels. GGT is often used alongside other liver tests to monitor liver health, especially in cases of suspected alcohol use, bile duct blockages, or other liver conditions.

Common Causes of Elevated GGT

High GGT levels may be linked to liver diseases (such as hepatitis), alcohol consumption, certain medications, or conditions affecting bile flow. However, GGT can also rise in other situations, like heart disease or certain cancers.

How the Test Works

A blood sample is taken, and the enzyme activity is measured using a lab technique that detects how quickly it breaks down a specific chemical substrate. This provides a quantitative measure of GGT levels in the blood.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid alcohol for 24 hours before testing, as it can temporarily raise GGT levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

GGT

Frequently asked questions

What does a high or low GGT level mean?
Elevated GGT levels often signal liver stress or damage, but they can also be influenced by other factors like medications, heart conditions, or metabolic issues. Your doctor will consider your overall health and other test results to interpret results accurately.
How often should I get this test?
Your doctor may recommend GGT testing periodically if you have liver concerns, take medications that affect the liver, or have conditions like alcohol use disorder. Follow-up tests are usually scheduled based on your individual needs and symptoms.
Can lifestyle changes affect GGT levels?
Yes, reducing alcohol intake, maintaining a healthy diet, and avoiding certain medications that may strain the liver can help lower GGT levels over time. Always discuss lifestyle changes with your healthcare provider before making adjustments.
  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