Aspartate Aminotransferase (AST)
An aspartate aminotransferase (AST) test measures the amount of
enzyme in the blood. AST is normally found in
red blood cells,
liver, heart, muscle tissue,
pancreas, and kidneys. AST formerly was called serum
glutamic oxaloacetic transaminase (SGOT).
Low levels of AST are normally found in the blood. When body tissue
or an organ such as the heart or liver is diseased or damaged, additional AST
is released into the bloodstream. The amount of AST in the blood is directly
related to the extent of the tissue damage. After severe damage, AST levels
rise in 6 to 10 hours and remain high for about 4 days.
The AST test may be done at the same time as a test for alanine
aminotransferase, or ALT. The ratio of AST to ALT sometimes can help determine
whether the liver or another organ has been damaged. Both ALT and AST levels
can test for liver damage.
Why It Is Done
An aspartate aminotransferase (AST) test is done to:
- Check for liver damage.
identify liver disease, especially
cirrhosis. Liver disease may produce symptoms such as
pain in the upper abdomen, nausea, vomiting, and sometimes
- Check on the success of
treatment for liver disease.
- Find out whether jaundice was caused by a blood disorder or liver
- Keep track of the effects of
cholesterol-lowering medicines and other medicines
that can damage the liver.
How To Prepare
Tell your doctor if you:
- Are taking any medicines. Many medicines can
interfere with test results. Your doctor may instruct you to stop taking
certain medicines for several days before having an AST test. Some
herbs and natural products (such as echinacea and
valerian) also can affect AST results.
allergic to any medicines.
- Are or might be
Talk to your doctor about any concerns you have regarding the need
for the test, its risks, how it will be done, or what the results may mean. To
help you understand the importance of this test, fill out the
medical test information form(What is a PDF document?).
How It Is Done
The health professional taking a sample of your blood will:
- Wrap an elastic band around your upper arm to
stop the flow of blood. This makes the veins below the band larger so it is
easier to put a needle into the vein.
- Clean the needle site with
- Put the needle into the vein. More than one needle stick
may be needed.
- Attach a tube to the needle to fill it with
- Remove the band from your arm when enough blood is
- Put a gauze pad or cotton ball over the needle site as
the needle is removed.
- Put pressure on the site and then put on a