biotech Lab Marker

AST Blood Test: Liver & Heart Enzyme Explained

AST (Aspartate Aminotransferase) is an enzyme found in the liver, heart, muscles, and kidneys. Unlike ALT which is liver-specific, elevated AST can indicate damage to multiple organs. The AST/ALT ratio helps distinguish liver disease from muscle or heart damage.

check_circle

Normal Range

10 – 40 U/L

science

Unit

U/L

What Your Results Mean

Normal

Normal AST indicates no significant damage to the liver, heart muscle, or skeletal muscle.

High

High AST can indicate liver disease, heart attack, muscle injury, or hemolysis. When AST rises with ALT, liver disease is likely. When AST rises without significant ALT elevation, muscle or heart involvement is suspected.

Low

Low AST has no clinical significance.

Frequently Asked Questions

What is a normal AST level? expand_more

Normal AST is 10–40 U/L for most adults. Values above this range suggest damage to the liver, heart, or muscles.

What does AST/ALT ratio mean? expand_more

An AST/ALT ratio above 2:1 is typical of alcoholic liver disease. A ratio below 1 (ALT higher than AST) is more common in non-alcoholic fatty liver disease and viral hepatitis.

Can exercise raise AST? expand_more

Yes — intense exercise releases AST from muscle cells, causing temporary elevation. This is why blood tests are ideally done before strenuous exercise.

What causes high AST without high ALT? expand_more

This pattern suggests muscle damage (rhabdomyolysis), heart attack, or hemolysis rather than primary liver disease.

biotech

Have a lab test? Get AI-powered results in minutes.

Upload your lab report and receive a detailed, plain-language explanation of every marker.

upload_file Analyse My Results