What is AST?
AST (aspartate aminotransferase) is an enzyme found mainly in the liver, heart, and skeletal muscle. A blood test for AST is usually done to detect liver damage and disorders. When these organs are damaged, the enzyme is released into the blood, raising blood values. AST is a useful test for early detection of liver damage. AST does not have much significance when taken by itself. It is often included in a comprehensive health or wellness panel to evaluate liver function and is also used when liver disease or damage is suspected.
Why test AST?
There are many reasons to test AST. Testing AST is an important part of a health check because it helps you discover your risk factors for lifestyle diseases in time to take action. Liver health is affected by your alcohol consumption, weight, virus exposure, or other lifestyle factors. Additionally, monitoring AST levels can help track changes in your blood values as you make lifestyle changes, take supplements, or undergo treatments.
What causes low AST?
A low level of AST in the bloodstream is the normal result. Vitamin B6 deficiency, alcoholism, old age, or underlying health conditions such as liver, kidney or inflammatory diseases can cause extremely low AST.
Symptoms of low AST
Low levels of aspartate aminotransferase (AST) are generally not associated with specific symptoms and are usually not a cause for concern. AST is an enzyme found in various tissues in the body, primarily in the liver and heart. Low AST levels are typically normal and do not indicate any health issues. However, very low levels of AST may sometimes be seen in individuals with vitamin B6 deficiency, but this is rare and not usually accompanied by clear symptoms related to the low AST itself. If you have concerns about your AST levels or overall health, it’s always best to consult with a healthcare provider.
What causes high AST?
Liver problems are the most common cause of high AST. Liver toxicity from alcohol, drugs or other substances can also elevate levels, sometimes up to 100 times normal values. Viral hepatitis can take up to six months to return to normal.
Elevated AST may indicate cirrhosis (scarring of the liver), muscle injury, heart problems, pancreatitis or mononucleosis (an infection caused by a virus called Epstein-Barr) or autoimmunity. However, if your results are not in the normal range this does not necessarily mean that you have a medical condition as many factors may affect your results. These include older age, gender, an inflammatory diet void of nutrients, alcohol intake, smoking, and some medications.
Symptoms of high AST
High levels of aspartate aminotransferase (AST) can indicate liver damage or disease and may cause several symptoms. These include persistent fatigue, jaundice (yellowing of the skin and eyes), abdominal pain (especially in the upper right side), nausea and vomiting, dark urine, loss of appetite, swelling in the legs and ankles, and generalized itching. If you experience these symptoms, it is important to consult a doctor for proper evaluation and treatment, as high AST levels can signify serious health issues, particularly with the liver or heart.
More information
AST and ALT are considered two of the most important tests to detect liver injury (although ALT is more liver-specific than AST, and AST is less likely to be raised). AST levels are used with the results of other tests, such as alkaline phosphatase (ALP), total protein, and bilirubin to help determine which form of liver disease is present.
AST may be used to monitor those taking medications that are potentially toxic to the liver. This test may be used together with ALT as part of a liver panel or comprehensive metabolic panel (CMP) to assess liver function and possible liver diseases. Values that are slightly outside the reference range can be normal. Reference ranges are not perfect and approximately 5% of healthy individuals may have results outside the reference range.
Preparations for the test
Avoid fatty foods and alcohol the day before the test.
On the day of the test
Remember to take your ID. with you when going to take a test.