AST test

What is AST?

AST, or asparagine aminotransferase, is one of the so-called hepatic values, i.e. enzymes which are mainly found in the liver and muscles. These enzyme should normally be present inside cells. Therefore, their increased blood concentration levels indicate cellular (e.g. hepatic cells) damage. AST concentration levels are determined with a view to diagnosing and monitoring liver diseases.

AST test

The liver has very important functions in the body. It is responsible for neutralising toxins and takes part in nutrient metabolism (e.g. fats). The liver demonstrates a high regeneration potential, which – to a large extent – depends on diet. The diagnostic process of liver (hepatic) diseases is based on the determination of AST concentration.

AST is an intracellular enzyme which is produced in the liver, cardiac muscle and skeletal muscles. In healthy individuals, the amount of this enzyme is not very large. Its increased levels indicate the presence of liver damage.

The AST test is used:

• in the diagnostics of liver damage and diseases,
• in monitoring the treatment of liver diseases.

Increased AST concentration levels are observed during cardiac necrosis, poisoning with drugs that are toxic for hepatic cells, muscle damage, as well as viral and alcoholic hepatitis.

AST test – when?

The AST test is done when there is suspicion of liver damage or disease, manifested amongst others as:

• jaundice,
• skin itching,
• easy fatigability,
• reduced appetite,
• decreased body weight,
• nausea and vomiting,
• pain in the right subcostal region,
• menstrual disorders, amenorrhea (the absence of menstrual bleeding), including infertility,
• dermal (skin) lesions,
• coagulation disorders leading to haemorrhages
• dark urine or light colours of the stool.

The AST test is also recommended in:

• individuals whose relatives suffered from a liver disease,
• alcoholics,
• diabetic individuals,
• obese individuals,
• individuals on drugs which may lead to liver damage.

Elevated AST levels may be caused by:

• liver damage,
• liver cancer,
• skeletal muscle damage,
• cardiac muscle damage,
• hepatitis virus infection,
• the use of medications that negatively affect liver functions.

AST – preparation and the test

The AST test does not require any particular preparation. Patients should be on an empty stomach (a 12-hour break from the last meal). The result may be unreliable due to:

1. physical exercise,
2. coffee consumption,
3. medication use,
4. alcohol consumption.

A blood sample is collected from the ulnar (elbow) vein according to the following procedure:

1. disinfecting the skin,
2. fitting a tourniquet,
3. applying pressure at the collection site.

The material collection lasts from a few to a dozen seconds.

AST – preparation for the test

On the day before the test:

• Avoid consuming large and fat meals and drinking alcohol for 24 hours before the test.
• Refrain from drinking coffee and tea for at least 12 hours before blood collection.

On the day of the test:

• Patients should be on an empty stomach, which means that no meals can be consumed for about 12 hours before the test.
• They are allowed to drink a small amount of water in the morning hours.
• Where possible, the test should be performed before patients take their morning dose of medicines, unless their physician instructs otherwise.
• The blood should be collected in the morning hours.
• Before the test, patients should remain at rest for 10-15 minutes (in a sitting position).
• Physical exercise, including moderate effort, such as walking or climbing stairs, may alter the values of laboratory tests.

AST results

• Test results are available within 3 working days.
• It is possible to collect them at the reception desk of a selected centre.
• The results can be accessed online. For this to be possible, it is necessary to collect a password at the reception desk of a selected centre.