Why is AST elevated in blood, what does it mean?

Blood test AST is a biochemical blood test, which determines the amount of the intracellular enzyme aspartate aminotransferase.

This method of analysis is used to diagnose diseases of the myocardium, liver and muscle disorders, usually assigned simultaneously with blood tests of ALT, as well as analysis of bilirubin.

This analysis allows you to identify the amount of cellular enzyme AST in the tissues of the liver, kidneys, heart, skeletal muscles, nervous system and other organs. If during the analysis of blood, AST transcript shows a high amount of aspartate aminotransferase in the tissues of the body, this allows conclusions to be drawn about the presence of abnormalities in one or another organ.


The amount of AST in the blood depends on the gender of the patient:

  • for women, the index is within 31 U / l;
  • for men, the normal figure is up to 41 U / l;
  • in newborns, 25 to 75 U / l is considered the norm;
  • in children aged one to eighteen years - 15 to 60 U / l.

As can be seen, the activity of aspartate aminotransferase in the woman’s body is slightly lower than in the man’s body, and in children it is higher than in adults.

Indications for analysis

AST blood test is necessary for accurate determination of the intracellular enzyme aspartate aminotransferase, which is detected as a result of biochemical analysis.

Assign it in the following cases:

  • All pathologies of the liver.
  • All types of jaundice and metabolic bilirubin.
  • Autoimmune diseases.
  • Endocrine diseases.
  • Infections.
  • Intoxication.
  • Malignant tumors.
  • Allergic skin diseases.
  • Long-term treatment with antibiotics, chemotherapy and various toxic drugs.
  • Diseases of the circulatory system.
  • Chronic and acute heart disease.
  • Renal failure.
  • Injuries to the abdomen and chest.
  • Preparing for a complex surgery.
  • Purulent septic pathology.
  • Encephalopathy of unknown etiology.
  • Disorders of bile outflow, gallstone disease.
  • Pancreatitis is chronic.
  • Evaluation of the treatment of hepatic and cardiac pathologies

It is important to note that 7-15 days before donating blood to AST, the medication should be completely excluded. However, if this cannot be done, the doctor, before taking blood, should be informed about the number of drugs and their daily dosage.

Causes of increased AST

Why is AST increased, and what does it mean? In adults, the level of AST increases with diseases accompanied by the breakdown of tissues rich in these enzymes. Excessing AST by 2–5 times is considered moderate, 6–10 times is moderate, higher rates are a significant increase.

Most often, AST above the norm is diagnosed with:

  • acute or chronic hepatitis;
  • alcohol intoxication;
  • the development of obstructive jaundice;
  • destruction of liver cells;
  • dermatomyositis;
  • mesenteric infarction;
  • infectious mononucleosis;
  • progressive muscular dystrophy;
  • fatty liver;
  • local radiation damage;
  • acute pancreatitis;
  • necrosis of cardiomyocytes (heart muscle cells);
  • necrosis or injury of skeletal muscle cells;
  • poisoning with chloroform, pale toadstool, carbon tetrachloride;
  • therapy of hepatotoxic drugs and drugs that cause cholestasis.

The determination of the level of AST is often carried out in combination with ALT. The availability of data on the level of these two enzymes suggests the localization of the pathological process, its severity and build a forecast. There is a so-called Rytis coefficient - AST / ALT ratio. Normally, this indicator is 1.33. With heart disease, it increases, and with liver pathology it decreases (with the exception of alcohol damage).

What to do

It should be clearly understood that increasing AST is not the cause of the disease. This is its consequence. Therefore, only the elimination of the causative disease will be able to interrupt the causal relationship, which will be reflected in the normalization of AST activity and will become the criterion of victory over this disease.

Any cases of increasing aspartate aminotransferase are a reason for seeking specialized medical care. Behind this harmless and asymptomatic symptom is often hiding serious chronic diseases that will manifest themselves only after a while.

Since this symptom signals the destruction of cells containing this enzyme (heart, liver, muscles), it is necessary to deal with the diagnosis and treatment of diseases of these organs.

Watch the video: Liver and pancreatic enzymes explained. AST, ALT, GGT, ALP, Amylase& Lipase (November 2019).

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