Gamma-Glutamyl Transferase (GGT) – Serum
Gamma-glutamyl transferase (GGT) is an enzyme found in the liver, bile ducts, and other organs. It helps break down amino acids and is often measured to assess liver function or detect potential liver damage.
["GGT helps doctors check liver health and identify possible liver issues."]
Key facts at a glance
- LOINC
- 2322-6
- Short code
- GGT Amn-cCnc
- Synonyms
- GGT Amn-cCnc
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- 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
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order a GGT test to evaluate liver health, especially if you have symptoms like jaundice (yellowing of skin/eyes), abdominal pain, or unexplained fatigue. It’s also used to monitor liver function in people with known liver conditions, such as hepatitis or cirrhosis. Additionally, GGT can help detect bile duct blockages or alcohol-related liver damage.
What Does a High or Low GGT Level Mean?
Elevated GGT levels may suggest liver problems, including alcohol use, certain medications, or conditions like hepatitis. However, GGT alone isn’t diagnostic—it’s often used alongside other tests. Low GGT levels are less common but may occur in certain genetic disorders or liver diseases like primary biliary cholangitis.
How Is the Test Performed?
A blood sample is drawn from a vein, usually in your arm. The blood is then sent to a lab for analysis. The test measures the enzyme activity in your serum, which is the liquid part of blood after clotting.
What Are Common Causes of Abnormal Results?
Factors that can raise GGT levels include heavy alcohol consumption, certain medications (like antibiotics, antifungals, or statins), fatty liver disease, or bile duct blockages. Conversely, low GGT levels are rare and may relate to specific genetic or metabolic conditions.
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.
GGT is a sensitive marker for liver injury or dysfunction. While it doesn’t pinpoint the exact cause, it helps doctors assess whether liver problems are present and guide treatment decisions. It’s often used in combination with other tests, such as liver enzymes (ALT/AST) or imaging, for a fuller picture.
Short name
GGT
Frequently asked questions
How long does it take to get results?
Can lifestyle changes affect GGT levels?
Is this test painful?
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