Aspartate aminotransferase (AST) is an enzyme found mostly in the liver but also in red blood cells, heart and other muscles. When liver, red blood cells, heart or muscle cells are injured they release AST into the blood.
AST can be measured by itself but more often it is measured as part of a group of tests known as Liver Function Tests (LFTs). These are all performed on the same blood sample and they give information about how your liver is working.
Why get tested?
The AST test can be ordered by itself but more often as one in the panel of tests known as Liver Function Tests (LFTs) if you have symptoms that suggest a liver disorder. LFTs measure the levels of several different substances in the blood that are either produced by the liver cells as part of their normal function or released into the blood when liver cells are damaged.
They include gamma-glutamyl transferase (GGT) alanine transaminase (ALT), alkaline phosphatase (ALP), bilirubin (a breakdown product from red blood cells removed from the body by the liver and spleen), and albumin (a protein produced by the liver). By considering the levels of each substance in the context of the others it’s possible to decide which form of liver disorder someone has.
Having the test
Reading your test report
Your results will be presented along with those of your other tests on the same form. You will see separate columns or lines for each of these tests.
Your results will be compared to reference intervals (sometimes called a normal range).
If your results are flagged as high or low this does not necessarily mean that anything is wrong. It depends on your personal situation. Your results need to be interpreted by your doctor.
AST Reference Intervals
The reference intervals for this test are common reference intervals which means that most laboratories in Australia should be using this same target range.
Male 5 - 35 U/L
Female 5 - 30 U/L
Questions to ask your doctor
The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell them everything you think might help.
You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.
Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:
Any more to know?
Hepatitis is an inflammation of the liver. There are two major forms: acute and chronic.
While many things can harm the liver, the major causes of liver disease are infection by viruses that target the liver, drinking too much alcohol, and obesity with diabetes . Medicines can also damage the liver. Your doctor may suggest testing your liver from time to time if you are taking a medication that puts you at higher risk of liver damage. Some inherited diseases can occasionally damage the liver.
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