Liver Disease and Blood Tests – The Normal Levels Of AST and ALT

Liver Disease and Blood Tests – The Normal Levels Of AST and ALT

AST (aspartate aminotransferase) and ALT (alanine aminotransferase) are two of the most common blood tests when it comes to liver damage. These enzymes are present in the liver cells but when the organ is damaged in any way, they get released into the bloodstream, making a simple blood test able to detect these injuries.

AST and ALT Enzymes

AST is also known as SGOT, and ALT as SGPT (serum glutamic pyruvic transaminase). Between the two enzymes, there’s one big difference less known by the patients. AST is also present in the heart, kidneys cells and even in the muscles. Meaning that if the level of AST is high, it can indicate other diseases besides liver failure. On the other side, ALT is mostly present in the liver, being a better indicator of liver injury than ALT.

Recommended levels of ALT and AST

A healthy person should have the AST level between 5 and 40 units/L of serum, and ALT values of 7 – 56 units/L of serum. The results provided by labs can differ, depending on the methods they use. They usually mention it in the report if they use specific methods and techniques.

Reading the ALT and AST levels

Although a high level of these enzymes indicates liver injury, your doctor should study your complete medical history before coming to the conclusion that you suffer from liver damage, because the AST level can be caused by a lot of other reasons including muscle disease, hepatitis A or hepatitis C.

Many doctors and medical publications claim that ALT and AST show liver function, but this is not always true. So before thinking that you suffer from liver damage, go to your doctor with a complete medical history.


I am a pop culture and social media expert. Aside from writing about the latest news health, I also enjoy pop culture and Yoga. I have BA in American Cultural Studies and currently enrolled in a Mass-Media MA program. I like to spend my spring breaks volunteering overseas.

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