What is Gamma GT?
Liver Health

What is Gamma GT?

Written by

Lauren Dobischok
16 May, 2022

Medically checked article All HOMED-IQ content is reviewed by medical specialists

Gamma GT is a blood value that can be measured at home with a simple finger prick. This blood value is important in investigating whether there is a problem with the liver. Homed-IQ offers several types of home health tests, including tests with which the Gamma GT value can be measured. These tests include the liver function blood test and the liver and kidney function test.

What is Gamma GT?

Gamma GT, also known as gamma-glutamyl transferase (GGT), is an essential blood enzyme. Gamma GT is important because it converts nutrients into substances that the body can then use (Dutch Association for Clinical Chemistry and Laboratory Medicine, 2016). There is usually a limited amount of GGT present throughout the body, with most of the enzyme located in the liver. If the liver is damaged in some way, excess Gamma GT can leak into the bloodstream. As a result, a Gamma GT is an important biomarker in a liver health test. Along with other markers, the level of Gamma GT in your blood can indicate how well your liver is functioning. 

Why is Gamma GT important?

Gamma GT is produced in the liver to contribute to the conversion and digestion of nutrients. When the liver no longer functions GGT in the blood can rise. Usually, Gamma GT is tested alongside ALAT and ASAT to assess liver health. A damaged liver can cause health problems and severe liver damage may even require a liver transplant. If there is damage to the liver, Gamma GT value functions as an indicator for determining this damage.

What are normal Gamma GT values?

Normal Gamma GT values differ between men and women. For men, a reference value of 10-40 40 U/L applies. For women, the reference value is lower, namely between 6-25 U/L (Jellinek, 2014). Most laboratories use the following reference values:

< 45 U/L (men)

< 35 U/L (women)

What is elevated Gamma GT?

Gamma GT is too high if it exceeds the target values. Based on the standard target values that most laboratories use, Gamma GT is too high if it exceeds 45 U/L in men, and 35 U/L in women. However, it is possible that an individual may have a GGT value slightly above these targets with no actual liver damage. In this case, further testing and guidance from a physician is needed.

Testing Gamma GT

By testing your Gamma GT value, you gain insight into the functioning of your liver and can identify potential liver damage before it becomes serious. Homed-IQ’s home liver function involves collecting a small blood sample from home via a simple finger prick. The sample is then analyzed by a certified laboratory with results available in a matter of days.

The causes of an elevated Gamma GT value

There are a number of possible reasons for an elevated Gamma GT value. The most common cause of a highly elevated GGT value is a disorder of the liver, or a problem with the bile ducts (Maag Lever Darm Stichting, 2013). A slightly elevated GGT value can be due to a number of different factors, such as alcohol use, certain medications, extreme obesity and fatty liver. There are a number of other reasons for a value that is elevated:

  • Old age
  • Heart attack or stroke
  • Diabetes
  • Epilepsy

Are there any diseases related to Gamma GT?

There are several diseases related to Gamma GT. The value may, for example, rise in the event of conditions like diabetes and epilepsy. Cardiovascular disorders such as heart attack or stroke can also cause the GGT value to rise above normal levels. In addition, liver cirrhosis as a result of alcohol abuse can lead to an elevated Gamma GT value.

What happens if my Gamma GT is too high?

Elevated Gamma GT often causes no symptoms at all, especially in the early stages of liver damage.  If symptoms do occur, they usually include:

  • General weakness
  • Fatigue
  • Decreased appetite
  • Nausea and abdominal pain
  • Yellow face or yellow eyes

How do I lower my Gamma GT level?

There are several ways to lower Gamma GT. It is important to know the cause first, because by tackling the cause, the value can be lowered more quickly. For example, if you drink too often and consume large quantities of alcohol, stopping this will lower your GGT value. The value can even decrease by half after a few weeks of abstaining from alcohol. GGT values usually return to normal after three months of lifestyle changes. In the case of being extremely overweight, losing weight often reduces the value. If it is due to a condition or illness, such as diabetes or epilepsy, please contact your doctor for further guidance.

About the author

Lauren Dobischok

Lauren is a health scientist and science communicator currently living in the Netherlands. Originally from Canada, she completed a Research Master’s in Health Sciences at the Netherlands Institute of Health Sciences at Erasmus University Rotterdam (NIHES) with a specialisation in epidemiology. Prior to her master’s degree, she completed a Bachelor’s degree in Health Sciences at Simon Fraser University. With a background in public health, her goal is to create accurate scientific content that is easy to understand and empowers people to make informed decisions. Within Homed-IQ, Lauren works as a Product Developer and Content Lead, working closely with physicians and scientists on medical devices for Homed-IQ’s new products and written communications.