High AST, Normal ALT: The Overlooked Condition You Should Know

High AST with normal ALT can seem contradictory. If both enzymes appear on a liver blood-test panel, why would only one be elevated?

In this educational video, Dr. Kevin Lowe explores macro-AST—an uncommon explanation for an AST result that remains high despite otherwise reassuring findings. When AST joins with an antibody or another molecule, it forms a larger complex that can stay in the bloodstream longer than usual. This may produce persistently elevated AST activity without ongoing tissue damage.

Discover why AST is not specific to the liver, which patterns may prompt consideration of macro-AST, and how laboratories investigate it using PEG precipitation and other specialized methods. The video also explains the limitations of refrigerated-sample testing: some macro-AST complexes lose activity during storage, while others remain stable.

Normal ALT alone does not rule out liver disease or confirm macro-AST. The aim is to understand why the complete clinical picture matters—and how recognizing an unusual laboratory finding may help avoid unnecessary investigations.

Presented by Dr. Kevin Lowe, making medical science accessible so you can have more informed conversations about your health.

For general education; not a substitute for individualized medical advice, diagnosis, or treatment.

#HighAST #NormalALT #MacroAST #BloodTests #LiverHealth