Gamma GT test (clinical analysis)



There gamma-glutamyl transferase, also known as GT or GGT range, is an enzyme found mainly in the liver. When the liver is damaged or the flow of bile is blocked, the concentration of GGT in the blood increases.

The gamma GT test, in fact, is useful for detecting liver disease and damage to the bile duct. It can also be used to understand why another enzyme, la alkaline phosphatase (ALP).

Both ALP and gamma GT are elevated in bile duct diseases and some liver diseases, while only ALP is elevated in bone diseases. If the gamma GT concentration is normal in a person with a high ALP value, bone disease is more likely to be the cause.

The GT range can also be used for alcohol abuse screening (it will be high in approximately 75% of long-term drinkers).

When to test

The doctor usually requests the GT test range together with other tests when there are signs, or clinical manifestations (symptoms) in a person, that suggest liver disease.

Some of the ailments linked to liver damage include:

  • jaundice
  • nausea
  • He retched
  • abdominal bloating (around the stomach area)
  • abdominal pain
  • itch (severe itching)
  • tiredness

There GT range it is increased in most diseases that cause damage to the liver or bile ducts but alone is usually not useful in distinguishing between the different causes of liver damage. However, there are studies that indicate that the gamma GT test can be used, together with other tests, to predict the presence of liver fibrosis (i.e. an abnormal production of connective-fibrous tissue) and non-alcoholic fatty liver disease (i.e. fat accumulation. called triglycerides).

The gamma GT test is also useful in determining the cause of a high ALP value.

In people with a history of alcohol abuse who are on treatment elevated GGT can be used to verify that the person is following the treatment program correctly.

The test

The amount of gamma-glutamyl transferase (GGT) it is determined by taking a simple blood sample from a vein in the arm. No specific preparation is required to perform the analysis.

Things to know

If you consume alcohol regularly, drinking alcohol in the 24 hours prior to the test can cause a temporary increase in your gamma GT values. In this case, your doctor may want to repeat the test to verify the result.

Smoking can also cause increased gamma GT concentrations.

Gamma GT levels increase with age in women but not in men, and are always slightly higher in men than in women.

Several drugs increase the concentration of gamma GT in the blood. These increases do not indicate liver damage. Please tell your doctor about any prescription or medication you are taking.


Usually, the doctor does not worry about low or normal results as the person is unlikely to have liver disease in this case.

Increased gamma GT concentrations, on the other hand, indicate that something is happening to the liver but not specifically what.In general, the higher the result, the greater the damage.

High concentrations may be due to liver disease, but also to congestive heart failure, alcohol consumption and the use of many drugs including non-steroidal anti-inflammatory drugs (NSAIDs), cholesterol-lowering drugs, antibiotics, antihistamines, antifungal agents, anticonvulsants , antidepressants and hormones such as testosterone Oral contraceptives (birth control pills) and clofibrate can reduce GGT concentrations.

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