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Gamma-glutamyl transferase (GGT) in serum/plasma

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 helps identify liver issues, including alcohol-related damage or bile duct problems."]

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

Key facts at a glance

LOINC
84931-5
Short code
GABABR Ab Ser Ql IF
Synonyms
GABABR Ab Ser 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
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 Does GGT Measure?

Gamma-glutamyl transferase (GGT) is an enzyme found in the liver, bile ducts, and other parts of the body. Elevated levels may indicate liver inflammation, injury, or blockage, such as from alcohol use, infections, or certain medications.

Why Might Your Doctor Order This Test?

Your doctor may request a GGT test to evaluate liver health, especially if you have symptoms like jaundice (yellowing skin/eyes), fatigue, abdominal pain, or if you’ve been diagnosed with conditions like hepatitis, cirrhosis, or alcohol use disorder.

Common Causes of Elevated GGT Levels

High GGT levels can result from liver diseases (e.g., hepatitis, fatty liver), alcohol consumption, certain medications (like antibiotics or painkillers), or bile duct blockages. It’s often checked alongside other liver tests for a full picture.

What to Expect During the Test

A blood sample is drawn from a vein in your arm. The test is quick and typically done in a lab. No special preparation is needed unless instructed by your provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

GGT

Frequently asked questions

How often should I get this test?
GGT levels alone aren’t diagnostic for liver disease—they’re often used alongside other tests (like ALT or bilirubin) to guide treatment decisions. Your doctor will interpret results in context of your symptoms and medical history.
Can lifestyle changes lower GGT levels?
Yes! Reducing alcohol intake, avoiding certain medications, and maintaining a healthy diet may help lower elevated GGT levels over time. Always follow your doctor’s advice.
What if my GGT is high but I don’t have obvious liver symptoms?
Even without symptoms, high GGT can signal early liver stress. Your doctor may recommend further testing (like an ultrasound or additional bloodwork) to investigate the cause, such as fatty liver or metabolic conditions.
  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