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Serum/plasma mass concentration of gamma-glutamyl transferase (GGT)

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 can signal liver issues, including alcohol-related damage or other conditions requiring medical evaluation."]

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

Key facts at a glance

LOINC
27420-9
Short code
PG Amn-aCnc
Synonyms
PG Amn-aCnc
Category
glucose
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Is GGT Used For?

GGT is often checked alongside other liver function tests to identify problems like inflammation, scarring (fibrosis), or damage to liver cells. It may also be used to monitor liver health in people with known liver conditions or those exposed to substances that can harm the liver, such as alcohol.

Why Might Your Doctor Order This Test?

Your doctor may order a GGT test if you have symptoms like fatigue, abdominal pain, jaundice (yellowing of skin/eyes), or if they suspect liver issues after reviewing your medical history, medications, or exposure to potential liver toxins.

What Does a High or Low GGT Level Mean?

Elevated GGT levels often indicate liver problems, though they can also be influenced by factors like alcohol use, certain medications, or other health conditions. Low GGT levels are less common and may suggest certain genetic or metabolic conditions, but they’re not typically alarming unless paired with other test results.

How Is This Test Done?

A blood sample is taken from a vein in your arm. The sample is sent to a lab where it is processed to measure GGT activity. No special preparation is usually needed, but your doctor may advise avoiding alcohol or certain medications for a day or two before testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

GGT Level

Frequently asked questions

Why might my GGT level be higher than expected even if I don’t have obvious liver symptoms?
Higher GGT levels can be caused by factors beyond liver disease, such as heavy alcohol use, certain medications (e.g., antibiotics, antifungals, or pain relievers), or even smoking. Your doctor will consider your full medical history and other test results to understand the cause.
Can GGT levels be affected by diet or exercise?
Dietary factors like alcohol consumption or certain foods (e.g., fatty foods) can temporarily influence GGT levels, but they are not the primary driver of long-term changes. Exercise itself does not typically alter GGT levels unless it leads to muscle damage or other metabolic stress.
What should I do if my GGT test results are abnormal?
If your GGT level is elevated, your doctor may recommend follow-up tests, lifestyle changes (such as reducing alcohol or modifying medications), or further evaluation to identify the root cause. They will discuss next steps with you based on your overall health and symptoms.
  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