Blood tests are one of the many ways health care providers measure their patients’ overall health, and certain markers can be complicated. When looking at the various enzymes in the liver on a blood test report, one may see the abbreviation AST and wonder, what does AST measure? Knowing what AST means and how to measure it can help determine what needs to be done and how the body, and especially the liver and muscles, are functioning.

Blood tests are one measure to see how the liver is functioning, but what is AST?

AST, which is short for Aspartate Aminotransferase is an enzyme found in many body tissues. Some of the tissues AST can be found in are the liver, heart, muscles, and kidneys. AST has a role to assist in the process of metabolism of an amino acid, which is a necessary process for the production of energy and the functioning of cells.

It is normal for levels of AST in the bloodstream to be low, but as cell tissue in one of the stated organs are damaged, levels of bloodstream AST can increase due to leakage.

AST is an enzyme that is commonly found in liver function tests, also referred to as LFTs, which are used to help measure the health of the liver. Because of the function of the enzyme, AST can help determine if damaged tissue exists and the possible causes of the tissue damage.

Medical practitioners commonly analyze AST levels in conjunction with other tests including ALT (Alanine Aminotransferase). On its own, AST by itself can’t tell you what specific diagnosis you may have, but it points to the fact that other tests may be needed.

What are Normal Levels of AST?

The normal AST range may slightly differ from one laboratory to another, how the tests are conducted, and how the tests are interpreted. However, normal cellular functioning and a healthy tissue profile with little to no damage is expected to place a person in a low range.

In a single test, the AST result is expected to be interpreted in conjunction with other influencing factors from a person’s demographic (age, sex, and lifestyle) and health profile.

What are the Reasons for High AST Levels?

When they are elevated, AST levels reveal the presence of tissue damage. The area of damage can vary. The pre-dominant area of damage is the liver which is mostly  the result of infections like hepatitis, fatty liver disease, or liver damage from alcohol abuse.

However, AST is a non-specific liver test. Increased levels of AST may also have causes including but not limited to muscle injury from exercise, heart disease, and certain drugs. Hence, it is for the above reason that physicians often interpret AST in conjunction with other enzymes to determine the underlying issue.

Concerns About Low AST Levels

Low levels of AST are not typically seen as a cause for concern. They are not commonly associated with any serious issues, because most of the time, they reflect a normal bodily function.

As with any parameter, the interpretation of your levels should be done alongside other clinical and lab findings.

AST and ALT

AST and ALT are compared to one another because they are both released when there is damage to the liver. ALT levels are more liver specific though.The AST to ALT ratio can be very informative. Some patterns can suggest a specific liver disease and other can tell you if the cause of the increased enzymes is the liver or not.

When is the AST Levels a Problem?

A stand alone increase in AST can be of little concern, but an increase in AST in conjunction with a problem that is recurrent should be a cause for concern. The symptoms of jaundice, fatigue, abdominal pain and unexplained weakness should be evaluated.

The importance of measuring level of AST is that you can uncover potential issues before they worsen.

Keeping AST Levels Healthy

Overall health enables AST levels to be kept within the normal limits. Liver and muscle health can be supported by a balanced and nutritious diet, low and moderate alcohol intake, regular exercise, and management of health conditions.

In order to manage enzyme levels, and identify and address abnormal enzyme levels, routine health check-ups and timely blood tests are of critical importance.