Aspartate aminotransferase (AST) – what is it, when to do the test, interpretation of results

Proven content

Aspartate aminotransferase (AST) is an indicator enzyme of cytoplasmic and mitochondrial origin. It is found in the liver, heart cells, skeletal muscles, kidneys, erythrocytes, and the brain. The material needed for the AST examination is serum.

The concentration of this enzyme is the lowest in healthy people, then there are traces of it. AST is released into the blood in conditions of damage, e.g. of the liver or muscles. The concentration of this enzyme increases in 4-6 hours after the myocardial infarction and remains high for up to three days after the incident. Formerly, the determination of aspartate aminotransferase was the first test used to diagnose a heart attack. Currently, this designation is not so important as more specific tests have been introduced to determine myocardial ischemia. High concentrations can also be a consequence of cardiac surgery or intensive heart massage.

Before performing an AST test, inform your physician about all medications and ad hoc medications and dietary supplements you are taking, as well as about current diseases – especially in the case of coagulation disorders and the carrier of blood-borne pathogens (e.g. HIV, HBV, HCV).

AspAT study it is most often useful in the diagnosis of liver diseases. The activity of AST and the activity of ALT together form the test of the liver function tests. Small liver damage often does not give any symptoms, only the AST test helps to control the patient’s condition during the so-called treatment. hepatotoxic drugs (damaging the liver), in the case of alcoholism and in other conditions predisposing to liver disease (e.g. exposure to the hepatitis virus or severe obesity).

Thanks to the performed determinations, it is possible to diagnose: neoplastic diseases of the pancreas, obstruction of the bile ducts, liver or sickness damage and skeletal muscle damage.

AspAT – preparation for the test

1. serum.
2. on an empty stomach (at least 8 hours).
3. one-time blood sampling from a vein in the arm.
4. 1 Day.
5. not more than 510 nmol / l / s.
6. In diagnostics, the determination of the ratio of the activity of AST and ALT is used. Normally it is higher than unity. However, in diseases of the liver parenchyma, the de Ritis index is lower than 0,9. Monitoring the concentration of transaminases allows to assess the dynamics of the disease process in the organ.

Interpretation of AST results

A correct test result means that the organs (liver, heart) have not been damaged. In such a situation, further diagnostics are not undertaken, but it should be remembered that, for example, cirrhosis of the liver does not have to increase the AST enzyme. So what if the norm is exceeded (at least ten times)? This may indicate:

1. breakdown of cancerous tumors,
2. severe liver damage (viral inflammation, toxic effects of preparations),
3. myocardial infarction,
4. myocarditis,
5. intensive heart massage,
6. crushing skeletal muscles.

Occasionally, the elevation of the AST enzyme may be increased, but to a lesser extent. In such a situation, it is possible to suspect chronic hepatitis or liver involvement by viruses other than hepatitis viruses, hepatitis of a different etiology (fatty liver – e.g. in obesity and non-fatty – caused e.g. by less severe than the previously mentioned toxic effects of drugs), and conditions such as celiac disease, α1-antitrypsin deficiency, Wilson’s disease, and hemochromatosis.

Elevated AST enzyme may also have other causes:

1. infectious mononucleosis,
2. Burns,
3. kidney disease
4. heart attack (heart disease)
5. thyroid disease,
6. anemia,
7. condition after surgery,
8. kidney stones,
9. acute kidney failure,
10. inflammation of the bile ducts,
11. skeletal muscle diseases,
12. biliary obstruction,
13. fibrosis of the bile ducts.

While AST can be stated to be an indicator of liver damage, be sure to interpret the test result based on the overall clinical picture. Therefore, the result of the above examination should be consulted with a doctor each time, because the patient’s overall health condition and other laboratory tests are necessary for the correct assessment of the result. Note: Statins, aspirin, barbiturates and some herbs are a group of drugs that may increase AST as an undesirable effect.

Aspartate aminostransferase testing – who should do it regularly?

Systematic determination of AST levels should be recommended in:

1. people diagnosed with viral hepatitis,
2. women who use oral hormonal contraceptives or contraceptive patches
3. people taking large amounts of drugs that may irritate the liver,
4. people undergoing long-term hormone therapy,
5. people complaining of chronic epigastric pain, flatulence and indigestion.

IMPORTANT: a sick liver often does not cause any pain for a long time. Therefore, it is very important that everyone checks the condition of their liver from time to time by performing AST, AST or GOT tests.