De Ritis ratio (AST/ALT) calculator
Short answer: There is no single normal De Ritis ratio. With normal liver enzymes it is often close to 1 and means little. It becomes useful when AST or ALT is raised: below 1 is the usual pattern in fatty liver and viral hepatitis, and 2 or above is typical of alcohol-related liver injury.
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De Ritis ratio calculator (AST/ALT)
De Ritis ratio = AST ÷ ALT
Sources: De Ritis F, Coltorti M, Giusti G. An enzymic test for the diagnosis of viral hepatitis: the transaminase serum activities. Clin Chim Acta 1957;2(1):70-74.
In U/L
In U/L
Your result
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A pointer, not a diagnosis. Talk to a doctor about your result, and sooner if you feel unwell.
AST divided by ALT: a clue to the cause when liver enzymes are raised.
Normal range
Adult reference range.
- Low< 1 ratio
- Moderate1 – 2 ratio
- High≥ 2 ratio
What it measures
The ratio of two liver enzymes, AST and ALT, named after Fernando De Ritis, who described it in 1957. It does not measure the liver by itself. It shows which enzyme is leading when one or both are raised, and that pattern hints at the cause.
What moves it
Alcohol and liver scarring push AST up relative to ALT. Fatty liver and most viral hepatitis push ALT up more. Hard exercise and muscle injury raise AST, and some medicines move either enzyme.
How to bring it into range
Read it only alongside the enzyme values themselves. If either is raised, a doctor will usually check for fatty liver, alcohol, viral hepatitis and medicines, and may suggest an ultrasound or a liver-scarring test.
How fast it responds
It follows the enzymes: days to weeks after the cause changes.
Also reported as: AST/ALT ratio · SGOT/SGPT ratio · De Ritis
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Common questions
- What is a normal AST/ALT ratio?
- There is no single normal value. With both enzymes in the normal range the ratio is often close to 1 and means little. It is read only when AST or ALT is raised.
- How do you calculate the De Ritis ratio?
- Divide AST (also called SGOT) by ALT (also called SGPT), both in U/L. An AST of 60 and an ALT of 40 give 60 ÷ 40 = 1.5.
- What does an AST/ALT ratio above 2 mean?
- When the enzymes are raised, AST at least twice ALT is the classic pattern of alcohol-related liver injury. It is a pattern, not a diagnosis: muscle injury, some medicines and other liver conditions can do it too.
- Can exercise change the ratio?
- Yes. Muscle contains AST, so hard training in the days before the test can raise AST and the ratio with nothing wrong with your liver. Avoid heavy exercise for two to three days before a repeat test.
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Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.