What is the GGT value?
The term GGT stands for Gamma-GT or also Gamma-Glutamyltranspeptidase or Gamma-Glutamyltransferase. This describes an enzyme that is found in several organs. These include the spleen, small intestine, pancreas, kidney and, above all, the liver, as it has a high turnover of amino acids. The enzyme is membrane-bound and is involved in the transport of amino acids into the cells and initiates the breakdown of glutathione, an important molecule within the cells. It serves as an important laboratory parameter in the diagnosis of liver diseases such as hepatitis, intoxications and diseases of the bile ducts.
What is the normal value?
Adult men should have a GGT value below 66 U/l (units per liter). In adult women, a value below 39 U/l is aimed for. For children, different values apply, depending on age.
After the first year of life, values up to 25 U/l are considered acceptable. For 13 to 17-year-olds, the value for women should be below 38 U/l and for men below 52 U/l. As with all laboratory parameters, there are no uniform values with regard to the reference range.
This is due to the fact that in every human being the values that are present in perfect health are subject to a certain fluctuation. Some people have physiological laboratory values that lie outside the standard, even though no disease is present. In addition, depending on the laboratory, there are analytical methods that give slightly different results. For this reason, the reference range is often determined by each laboratory itself, which should be given the most attention in case of doubt.
How is the GGT increased?
The GGT value belongs together with the values of the GOT and GPT to the group of transaminases. These values are typically determined when liver damage is suspected. However, as already mentioned, GGT does not occur alone in the liver.
This is the reason why an elevated value does not necessarily indicate liver disease. This is referred to as low specificity. However, since the concentration of GGT in the blood of healthy people is very low, any increase is immediately noticed.
This is referred to as high sensitivity. Compared to the values of GOT and GPT, the value of GGT increases even with slight damage, since it is not located in the liver cells but within the cell membrane. Liver diseases that cause abnormal GGT levels include viral hepatitis, which can lead to the death of liver cells.
Depending on the type (hepatitis A-E), this can be severe or mild and can show acute or chronic progression. In acute, severe viral hepatitis, liver values such as GGT rise faster and more strongly than in chronic, less pronounced viral hepatitis. In addition, the GGT value can be increased if the liver is damaged by toxins.
These toxins include alcohol, some cytostatic drugs used in tumor therapy, aflatoxins, a poison derived from a mold, ovulation inhibitors used for hormonal contraception, and toxins of the tuber leaf fungus. With some substances such as alcohol, the effect occurs only after a long period of massive use, whereas with other substances such as aflatoxins, liver damage occurs more quickly. Also it can come in the course of the Pfeiffer’schen glandular fever or a bile jam to an increase of the GGT value.
A bile stasis does not necessarily have to be caused by the liver. However, since the bile flows from the liver to the gallbladder and small intestine, a reduced flow can lead to a backlog, which in turn damages the liver cells. Several organ systems are among the causes that cause an increase without being caused by the liver. For example, diabetes mellitus, the so-called diabetes, a burn or a brain attack can be the cause. In addition, acute pancreatitis, inflammation of the pancreas, various thyroid diseases, some muscle diseases or the regular intake of certain medications can cause an increase in the GGT level.
