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AST/ALT Ratio Calculator (De Ritis Ratio)

The ratio between two liver enzymes, AST and ALT, is one of the oldest clues to what is driving a raised liver test.

AST / ALT ratio

What the AST/ALT ratio shows

AST and ALT are enzymes that leak into the blood when liver cells are damaged. ALT is the more liver-specific of the two; AST also comes from muscle, heart and red blood cells. The ratio between them has been used since the 1950s — it is sometimes called the De Ritis ratio — as a clue to the cause of a raised liver test.

RatioPattern it is associated with
Below 1The usual pattern in metabolic (non-alcoholic) fatty liver disease
Around 1 or aboveCan appear as fibrosis advances, including in fatty liver
Above 2Classically associated with alcohol-related liver disease

Important limits

  • The ratio is a hint, not a test. Plenty of people break the pattern.
  • Both enzymes can be normal in someone who has significant liver disease, so a normal ratio proves nothing.
  • Hard exercise, muscle injury and some medicines raise AST without any liver problem at all.
  • It cannot distinguish between causes on its own; that takes history, imaging and sometimes further testing.

Before you act on this

FattyFix publishes general health information. It is not medical advice, it is not a diagnosis, and it is not a substitute for talking to a doctor, pharmacist or dietitian who knows your history. Never delay or stop treatment because of something you read here.

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