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A blood test for AST

What does the blood test AST?

AST, AST, AST or aspartate transaminase is the same concept that refers to one of the enzymes of protein metabolism in the body. This enzyme is responsible for synthesis of amino acids in the cellular membranes and tissues. Not all bodies of AST shows its activity. Moreover, this kind of activity can be attributed to specific enzymes, excess activity of which is indicative of a rather narrow range of pathological conditions. Most AST located in the myocardium (heart muscle), hepatocytes (liver tissue), neurons in the brain and muscle skeletal muscle. This is due to a fairly high level of metabolic processes in them, and the need for maximum adaptability of the cells to maintain their structure. This enzyme helps them in this.

While the structure of the cells containing AST is not broken, the amount of this enzyme in plasma is minimal and does not go beyond the norm. Once their integrity is broken, it leads to its excessive release into the systemic circulation. Such phenomena will be recorded in the form of natural increase activity of AST. Dependence must be directly proportional: the greater the cytolysis, the higher the level of AST. The importance belongs to the time after the beginning of the destruction of cells – the longer it takes, the less enzyme activity in the plasma.

Assigning biochemical study of blood, involves the analysis of enzymatic activity of plasma, among other indicators, which necessarily examines the AST. This requires venous blood, which is obtained by puncture of peripheral veins in the amount of 15-20 ml. It allows centrifugation to separate plasma from formed elements, which then yields different chemical reactions. In their course and determined the activity of AST in the blood.

A study of the AST allows to determine the presence of cell destruction (cytolysis) of the myocardium or liver. With the defeat of the other bodies, this index is not increased. Very often it is prescribed not only to confirm the destruction of specific tissues, and for the differential diagnosis or exclusion of cardiac and hepatic pathology.

When assigned to the analysis on the AST?

According to international protocols and standards for diagnosis of diseases, biochemical study of blood, including increased activity of AST, is a mustin many types of somatic pathology.

It can be:

  • Acute and chronic diseases of the heart and circulatory system;

  • Any liver disease;

  • Poisoning and intoxication;
  • Kidney damage with kidney failure;
  • Infectious pathology;
  • Purulent-septic conditions;
  • Different kinds of jaundice and disorders of bilirubin metabolism;
  • Signs of ascites and portal hypertension;

  • Encephalopathy of unknown origin;
  • Autoimmune diseases;
  • Acute pathology of the abdominal cavity surgery;
  • Any form of cholelithiasis and disorders of galeotto;
  • Necrotizing pancreatitis and chronic pancreatitis;

  • Endocrine pathology;
  • Allergic diseases of the skin;

  • Malignant tumors of any localization and suspicion of their metastasis;

  • Aggressive and prolonged treatment with chemotherapy drugs, antibiotics and other toxic drugs;
  • Preoperative preparation for any difficult interventions.
  • Assessment and treatment of diseases of the liver and heart;
  • Injuries to the thorax and abdomen with suspected injury of the heart or of the liver;

Norma AST in the blood

In order to properly evaluate the indicators of enzymatic activity of plasma in relation to the AST, we need to know the normal value. Most laboratories typically specify the next rule with the received indicator. This is because the definition of a measure of ASAT can be used different reagents and methods. Common species are considered the standards shown in the table.

The method of determining

The norm for men

The norm for women

The norm for children

Optical (IU)

To 40-41 IU

34-35 to ME

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The reaction in new York-Frenkel (mkmol/(h/ml))




If in the biochemical blood analysis the obtained values AST, which does not exceed guideline values, it speaks about the normal functioning of enzyme systems of the heart and liver and saved the integrity of the cellular composition of these organs. In the presence of clinical symptoms of the lesion must be explored in other specific markers (ALT, troponin, CPK, etc.)!

Causes of increase AST

Detection of increases of AST, especially repeated, can indicate such diseases:

  1. Acute myocardial infarction in the initial phases of its development. On the dynamics of the indicator can be judged on its vastness and the recovery period;

  2. Closed and open injuries of the heart;

  3. Myocarditis autoimmune or infectious origin;

  4. Acute and chronic viral hepatitis;

  5. Toxic lesions of the liver hepatotoxic poisons and drugs;

  6. Fat and alcoholic steatosis;

  7. Endogenous intoxication on the background of infectious and septic diseases of the internal organs and soft tissues;

  8. Severe chronic heart failure;

  9. Cholestasis due to mechanical obstruction in the bile ducts (stones, tumors, congenital anomalies);

  10. Violation of hepatic blood flow and portal hypertension;

  11. Cirrhosis of the liver with the preservation intact of the body. In decompensated cirrhosis the enzymatic activity of plasma in relation to AST reduced by the complete replacement of the liver by connective tissue;

  12. The liver metastases of malignant tumors;

  13. Primary cancer of the liver or bile ducts;

  14. The liver and heart in malignant myeloid forms of leukemia;

  15. Massive destruction of muscle tissue (myodystrophy, generalized myositis, compartment syndrome, reperfusion syndrome on the background of reduced blood flow in ischemic limbs;

Not any increase act must be perceived as a sign of cell cytolysis. If the rate is above normal values in several units of measurement, it still about what does not speak. Diagnostic importance is the increase of AST to more than two times higher than normal.

In this respect we can speak about:

  • A moderate increase (when ASAT is increased five times);
  • Average increase in (is logged when the index is up to ten times higher than normal);
  • Severe increase (the excess over the AST ten or more times compared to the norm).

The main diagnostic value of AST is heart damage during a heart attack. The study was conducted in the dynamics from short time intervals (about an hour). Any changes in the indicator exceeding the limit in cases of doubt favour a heart attack!

How to lower AST in the blood?

People who are looking for the answer to this question, we must clearly understand: the increase in AST is not an independent disease, and therefore there are no separate events for its fall!

Because this trait signals the destruction of cells containing the enzyme (heart, liver, muscle), you need to deal with the diagnosis and treatment of diseases of these organs. Only healthy tissue to function and to normalize all indicators of biochemical blood analysis, including AST.

It should be clearly understood that the increase of AST is not the cause of the disease. This is her consequence. Therefore, only the elimination of causative diseases can interrupt the causal link, which will be reflected in a normalization of activity of AST and will provide a measure of victory over this disease. Any increase in aspartate aminotransferase are the reason for seeking specialized medical assistance. For this innocuous and asymptomatic symptom often hidden chronic diseases, which manifest themselves only after some time.