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Serum/plasma concentration of gamma-glutamyl transferase (GGT) measured by enzymatic method

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

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.

Quick summary

["GGT helps 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
82977-0
Short code
GABABR IgG SerPl Ql IF
Synonyms
GABABR IgG SerPl Ql IF
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
CPT
82784
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 Gamma-Glutamyl Transferase (GGT)?

Gamma-glutamyl transferase (GGT) is an enzyme found in the liver, bile ducts, and other organs. It plays a role in breaking down certain amino acids and transporting them across cell membranes. Elevated levels may indicate liver problems, such as inflammation, scarring, or blockages.

Why Is This Test Done?

Doctors may order GGT testing to investigate symptoms like jaundice (yellowing of skin/eyes), abdominal pain, fatigue, or unexplained weight loss. It’s also used to monitor liver health in people with known liver conditions, such as hepatitis or cirrhosis, or those who drink alcohol.

Common Reasons for Testing

GGT is often checked alongside other liver tests (like ALT or AST) to get a full picture of liver function. It can also help determine if medications or alcohol are causing liver damage.

What to Expect Before the Test

No special preparation is needed, but you may be asked to avoid certain medications (like some painkillers or antibiotics) for a day or two before testing. Fasted blood draws are sometimes preferred, but this depends on your doctor’s instructions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

GGT (Serum/Plasma)

Frequently asked questions

What Does a High or Low GGT Level Mean?
Elevated GGT levels often signal liver stress, such as from alcohol use, infections (like hepatitis), fatty liver disease, or bile duct blockages. However, GGT can also rise in response to certain medications or conditions outside the liver (e.g., heart disease). Low GGT is less common but may occur in rare genetic disorders or liver disease progression.
How Does This Test Compare to Other Liver Tests?
GGT is more sensitive to alcohol and bile duct issues than other liver enzymes like ALT or AST, but it’s not specific enough alone. Doctors use it alongside other tests (e.g., bilirubin, albumin) to diagnose and guide treatment.
Can GGT Levels Change Over Time?
Yes, GGT levels can fluctuate with lifestyle factors (e.g., alcohol consumption, diet), medications, or underlying health changes. Regular monitoring may be needed if you have a chronic condition affecting the liver.
  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