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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 indicate 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
2323-4
Short code
GGT Smn-cCnc
Synonyms
GGT Smn-cCnc
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

Why is this test done?

Your doctor may order a GGT test to evaluate liver health, especially if you have symptoms like jaundice (yellowing skin/eyes), abdominal pain, fatigue, or if you’ve been diagnosed with conditions like hepatitis, cirrhosis, or alcohol use disorder. It can also help monitor treatment progress or screen for bile duct blockages.

What does a high or low GGT level mean?

Elevated GGT levels often suggest liver inflammation, alcohol consumption, or bile duct problems. Lower levels may indicate less liver stress, but they don’t always mean your liver is healthy. Results should be interpreted alongside other tests and symptoms.

How is the test performed?

A blood sample is drawn from a vein, usually in your arm. The serum portion is tested for enzyme activity using a specialized lab method.

What should I know before the test?

Avoid alcohol for at least 48 hours before testing, as it can raise GGT levels. If you’re on medications (like certain antibiotics or painkillers), let your doctor know, as they may affect results.

Reference range

Adult males: 8-61 U/L; Adult females: 5-36 U/LN/A

Specimen: serum

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 is a sensitive but nonspecific marker. While elevated levels often point to liver or biliary issues, they can also rise with certain medications, heart disease, or muscle disorders. It’s often used alongside other tests (like ALT/AST) for a fuller picture.

Short name

GGT Serum

Frequently asked questions

Can I drink alcohol before this test?
No, avoid alcohol for 48 hours before testing, as it can significantly affect your GGT results.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab.
Does this test hurt?
The blood draw may cause slight discomfort, but it’s usually over quickly. Most people tolerate it well.
  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