What liver values are there and what do they mean?
The term “liver values” is a synonym for the measurable concentration of certain enzymes in the patient’s blood serum, which primarily originate from the cells of the liver and are therefore regarded as liver-specific parameters or markers and can be determined within the framework of the diagnosis of liver and also bile duct diseases. Liver values are among the most frequently determined parameters in the patient’s blood serum. Usually the concentration of four enzymes is determined during blood sampling:
- The gamma-glutamyl transferase (short: gamma-GT/gGT),
- The glutamate pyruvate transaminase (short: GPT, also called alanine aminotransferase – short: ALT or ALAT),
- The glutamate oxaloacetate transaminase (short: GOT, also called aspartate aminotransferase – short: AST or ASAT) and
- The alkaline phosphatase (short: AP).
GPT is mainly found in the liver cells, whereas GOT, gGT and AP are also found in many other organ tissues and are therefore less liver-specific, which is why all four enzymes are usually determined simultaneously.
AP is very specific for biliary tract diseases, such as bile stasis caused by gallstones. The more liver values increase, the more specifically this indicates pathological processes in the liver area. The most sensitive liver and bile duct marker is gGT, while GOT and GPT often only increase when the liver cells are more severely damaged.
Nevertheless, the liver values in the blood of the patient may also be elevated without significant symptoms or other indications of liver or bile duct disease. An increase in the values does not necessarily have to be the result of a liver disease. Factors such as a constant intake of medication, alcohol and/or drug consumption, stress or an incorrect diet that is too rich in fats can lead to an increase in liver values. The following standard values are regarded as valid for the four important liver values (U/l = units per liter):
- GGT <60 U/l (men) and <40 U/l (women)
- GPT <50 U/l (men) and <35 U/l (women)
- GOT <50 U/l (men) and < 35 U/l (women)
- AP 40-130 U/l (men) or 35-105 U/l (women)