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Plasma or serum concentration of gamma-glutamyltransferase (GGT)

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

This test measures the amount of gamma-glutamyltransferase, an enzyme found in your liver and other organs. It helps doctors check for liver damage or disease.

Quick summary

["GGT can signal liver issues or exposure to certain substances."]

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

Key facts at a glance

LOINC
17451-6
Short code
PG IgA Ser Ql
Synonyms
PG IgA Ser Ql
Category
glucose
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Does GGT Measure?

Gamma-glutamyltransferase (GGT) is an enzyme that plays a role in breaking down certain proteins. Elevated levels may indicate liver problems, such as alcohol use, infections, or certain medications. It can also appear in other conditions affecting organs like the pancreas or kidneys.

Why Might Your Doctor Order This Test?

Your doctor may order a GGT test if you have symptoms like jaundice, abdominal pain, or if they suspect liver disease. It’s often used alongside other tests to diagnose or monitor conditions like hepatitis, cirrhosis, or alcohol-related liver damage.

How Is the Test Done?

A blood sample is taken from a vein, usually in your arm. The blood is then sent to a lab to measure GGT levels. No special preparation is needed, but you may be asked to avoid certain foods or medications for a short time before testing.

What Are Common Results?

Results are typically reported as a numerical value, but exact ranges can vary by lab. High levels may suggest liver issues, while low levels are less commonly significant. Your doctor will interpret results in the context of your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

GGT Level

Frequently asked questions

What causes GGT levels to be high?
High GGT levels can be caused by liver diseases (like hepatitis or cirrhosis), heavy alcohol use, certain medications (e.g., antibiotics, painkillers), or conditions affecting the pancreas or bile ducts. Other factors, such as smoking or obesity, may also play a role.
What if my GGT level is normal but I still feel unwell?
A normal GGT level doesn’t rule out liver or other health issues. Other tests, like liver enzymes (ALT, AST) or imaging studies, may be needed. Always discuss your symptoms and test results with your doctor—they’ll help determine the next steps.
Can lifestyle changes lower GGT levels?
Yes, reducing alcohol intake, eating a balanced diet, avoiding certain medications, and maintaining a healthy weight may help lower GGT levels over time. Your doctor can provide personalized advice based on your situation.
  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