Serum Gamma-Glutamyl Transferase (GGT) Activity
This test measures the activity of an enzyme called gamma-glutamyl transferase (GGT), which helps assess liver function and detect potential liver damage or disease.
["GGT can indicate liver issues, including alcohol-related damage or other conditions affecting bile flow."]
Key facts at a glance
- LOINC
- 100741-8
- Short code
- GGT Macro SerPl Ql
- Synonyms
- GGT Macro SerPl Ql
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 8
- Ref high
- 61
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82977
- SNOMED
- 3110003
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Is GGT Used For?
GGT is often used alongside other liver tests (like alanine aminotransferase, or ALT) to diagnose and monitor conditions such as hepatitis, cirrhosis, or bile duct blockages. It can also help evaluate liver damage from medications, alcohol use, or genetic disorders.
Why Might You Need This Test?
Your healthcare provider may order a GGT test if you have symptoms like jaundice (yellowing skin/eyes), fatigue, abdominal pain, or if you have risk factors like heavy alcohol use, chronic liver disease, or exposure to certain toxins.
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The blood is sent to a lab where the GGT enzyme activity is measured using an automated test method. Results are reported in units per liter (U/L) or millinternational units per milliliter (mIU/mL).
What Do Results Mean?
Elevated GGT levels may suggest liver problems, but they can also occur in other conditions like heart disease, pancreatitis, or certain medications. Your provider will interpret results in relation to your overall health and other test results.
Reference range
Adult males: 8-61 U/L; Adult females: 5-36 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: GGT plays a key role in liver metabolism and bile transport. While it’s not as specific as ALT for liver injury, elevated GGT often signals underlying liver stress, bile obstruction, or alcohol-related damage. It’s commonly used as part of a broader liver function panel.
Short name
GGT Serum
Frequently asked questions
What causes GGT levels to be higher than normal?
How long does it take to get results?
Can lifestyle changes lower GGT levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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