Why are ALT and AST elevated in blood, what does this mean?

The abbreviation AlAT stands for blood index of enzymes alanine aminotransferase, AsAT - asparaginaminotransferase. Indicators AST and ALT are included in the study of biochemical analysis of blood.

They were discovered in medicine relatively recently. Blood tests for AST and ALT are carried out jointly and, accordingly, their rate should be the same, and fully dependent on each other.

Such an indicator of tests, as an increase in ALT and AST in the blood by 2 or more times, should make you think about the occurrence of certain diseases. First you need to understand what is ALT and AST. What is the rate of these compounds in the blood and what should be done if at least one indicator is elevated?

What does the increase in ALT and AST above the norm

In adults, the content of ALT and AST in different organs is not the same, therefore an increase in one of these enzymes may indicate a disease of a certain organ.

  • ALT (ALaT, alanine aminotransferase) is an enzyme that is found mainly in the cells of the liver, kidneys, muscles, heart (myocardium is the heart muscle) and pancreas. When they are damaged, a large amount of ALT leaves the destroyed cells, which leads to an increase in its level in the blood.
  • AST (АСаТ, aspartate aminotransferase) is an enzyme that is also found in the cells of the heart (myocardium), liver, muscles, nerve tissues, and to a lesser extent in the lungs, kidneys, pancreas. Damage to the above organs leads to increased AST levels in the blood.

Basically, the rate of ALT and AST in the blood completely depends on the work of the most important parenchymal organ - the liver, which performs functions such as:

  1. Protein Synthesis
  2. The production of biochemical substances necessary for the body.
  3. Detoxification - excretion of toxic substances and poisons.
  4. Storage of glycogen - a polysaccharide, which is necessary for the proper functioning of the body.
  5. Regulation of biochemical reactions of synthesis and decomposition of most microparticles.

Normal blood levels of ALT and AST depend on gender. In an adult woman, the level of ALT and AST does not exceed 31 U / l. In men, normal ALT does not exceed 45 U / l, and AST 47 U / l. Depending on the child's age, the level of ALT and AST varies, while the content of ALT should not exceed 50 U / l, AST - 140 U / l (from birth to 5 days) and not more than 55 U / l for children under 9 years of age.

Depending on the equipment, which conducted the study, it is possible to vary the norms and reference values ​​of the level of enzymes. An increase in the rate of enzyme renewal, cell damage leads to an increase in the level of transaminases in the blood.

Causes of increased ALT and AST

Why are adult ALT and AST elevated, what does this mean? The most likely reason for the increase in liver enzymes in the blood are:

  1. Hepatitis and other liver diseases (cirrhosis, fatty hepatosis - replacement of liver cells with fatty cells, liver cancer, etc.).
  2. Increased ALT and AST as a result of diseases of other organs (autoimmune thyroiditis, mononucleosis).
  3. Myocardial infarction is necrosis (death) of the heart muscle, as a result of which ALT and AST are released into the blood.
  4. Diffuse damage to the liver, which can be caused by alcohol, drugs and (or) the action of the virus.
  5. Extensive injuries with muscle damage, as well as burns, cause an increase in ALT in the blood.
  6. Acute and chronic pancreatitis.
  7. Metastases or neoplasms in the liver.
  8. Reaction to drugs.
  9. Acceptance of anabolic steroids.

AST and ALT are important indicators of the condition of various organs. The increase of these enzymes indicates damage to organs such as the liver, heart, muscles, pancreas, etc. Thus, their blood levels decrease independently when the underlying disease is eliminated.


In order that the norm of the indicators does not exceed the permissible limits, it is recommended to avoid long-term medications.

If this is not possible due to a chronic disease, then it is better to take an AST on a regular basis so that it is not elevated or to prevent a serious increase in time. Periodically, you need to visit a gastroenterologist and a hepatologist who can identify a possible disease and prescribe treatment.

What to do if ALT and AST are elevated

In order to quickly and objectively understand the true reason for the increase in the activity levels of the enzymes ALT and AST, it is necessary to pass biochemical analyzes.

First of all, it is advisable to determine the levels of total bilirubin, alkaline phosphatase and GGTP (gamma-glutamyltransferase) and assess the degree of preservation of the main functions of the liver. To exclude the viral nature of liver damage (acute viral hepatitis), which is also accompanied by an increase in ALT and AST in the blood, it will be necessary to donate blood for specific antigens of viral hepatitis and specific antibodies to these antigens.

In some cases, a serum PCR test for the presence of HBV DNA and HCV RNA is indicated.

Watch the video: Liver and pancreatic enzymes explained. AST, ALT, GGT, ALP, Amylase& Lipase (January 2020).


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