Liver Enzyme Tests

The Canadian Liver Foundation recommends that liver enzyme tests be included in the regimen of blood tests that are part of an annual physical.  If the levels of AST or ALT are elevated, additional testing to determine an explanation for the elevation is required. Abnormal liver enzyme tests should never be ignored.  Not all abnormal liver tests will require treatment for the underlying liver disease, but all abnormal liver tests, even minimally abnormal tests require an explanation. 

Liver disease is difficult to diagnose because symptoms may be vague, easily confused with other health conditions or even non-existent. When diagnosed early however, many forms of liver disease can be treated or even reversed.

Liver enzyme tests – alanine aminotransferase (ALT) and aspartate aminotransferase (AST) are the most commonly used blood tests to determine the health of the liver.  These are sensitive tests of liver injury.  Normally found in liver cells, ALT and AST leak out of liver cells and into the blood when the liver cells are damaged. ALT is considered to be the more effective indicator of liver damage as AST is also found in other organs such as the heart and other muscles.  

Non-alcoholic liver disease and viral hepatitis are common and are increasing in prevalence.  These diseases may affect more than 10% of the population.  Since early identification and intervention are critical to the effective treatment of liver disease, routine screening of the adult population is warranted.

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