If your doctor has ordered an AST blood test, he is probably looking to measure tissue damage or liver damage. This test is also used to monitor the effects of efforts to manage cholesterol, since cholesterol-lowering medications can sometimes have undesirable side effects. It's important to understand what the test is for and what can skew results of this test so you can get an accurate reading and assessment of your tissue health.
AST stands for asparate aminotransferase. AST is an enzyme found in your bloodstream. It's normal to have low levels of AST in your blood, but your body responds to an injury of an organ or tissue by releasing more of this enzyme. In most cases of injury, AST levels rise over the six to ten hours following the injury and remain high for approximately four days. Your doctor may perform this test as part of an attempt to determine if you have had an internal injury.
Sometimes doctors perform an ALT blood test at the same time as performing an AST blood test. The combination of results from these two tests can help your doctor determine if you liver has been damaged through injury or other medical conditions that affect the liver such as liver disease, hepatitis or cirrhosis.
If you are not suffering from an internal injury, tissue damage or liver damage, you will probably have an AST blood level of between 10-34 international units per liter. Your doctor will probably issue further tests if you have an AST level over 35 IU/L. Some medications can skew the results of an AST blood test, so you should notify your doctor of any medications, supplements or vitamins you take. For example, both Echinacea and valerian can interfere with your AST reading. You should also notify your doctor if you may be pregnant or have engaged in strenuous exercise that may have resulted in mild tissue damage.
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