Glutamyl transferase

Glutamyl transferase
S -GT KL 1489

(in English S -GGT)

Glutamyl transferase is an enzyme located within the cells and plays a role in amino acid metabolism by facilitating the transfer of glutamyl groups between amino acids and peptides. The GGT enzyme is predominantly present in the liver and bile duct epithelial cells, but it can also be found in the pancreas, kidneys, and blood vessel endothelium.


The diagnosis and monitoring of liver and biliary tract diseases, along with the consideration of potential alcohol abuse.


1.0 mL of serum (min. 0.5 mL)

Storage and delivery

The sample can be refrigerated for up to a week, but for longer storage, it should be kept frozen. Delivery at room temperature, if it arrives within 24 hours.


Photometric, in accordance with IFCC recommendation. Accredited method.

Turnaround time

1 – 2 weekdays

Reference ranges 

1 month – 16 yrs         below 50 U/I
man, from 17 yrs  below 60 U/I
female, from 17 yrs  below 40 U/I
The reference values for adults are established using the data from the reference value material published by Huslab (2014).

Interpretation of results

Glutamyl transferase levels increase in both intra- and extrahepatic biliary obstructions, making it a more sensitive indicator compared to the ALP enzyme. GT is also elevated in cases of liver tumors, liver metastases, pancreatic malignancies, and pancreatitis. In acute hepatitis, GT increase is gradual, and the elevated value persists for weeks.

Heavy and regular alcohol consumption can raise GT enzyme activity, not necessarily indicating liver damage. However, upon cessation of alcohol consumption, GT levels return to normal within 2-3 weeks. Drugs like barbiturates, tricyclic antidepressants, antiepileptics, and oral contraceptives can also activate GT, leading to its increase.

GT levels are also elevated in conditions such as heart and lung infarction, pneumonia, heart failure, ulcerative colitis, and bronchial carcinoma. Obesity and fatty liver may also cause a slight increase in GT values.

In kidney diseases, GT activity does not increase in plasma, but GT may leak into the urine.


Last update 8.8.2023