AST/ALT Ratio Calculator (De Ritis Ratio)

Health

Calculate the AST/ALT ratio — also called the De Ritis ratio — by dividing your aspartate aminotransferase (AST) result by your alanine aminotransferase (ALT) result. Enter both liver-enzyme values in U/L and the calculator returns the ratio with a general interpretation. It is a screening aid, not a diagnosis.

Rates and fees change frequently. Always confirm the current figures with the official authority before relying on this result.

Formula

AST/ALT Ratio = AST (U/L) ÷ ALT (U/L)
  • The ratio simply divides the AST value by the ALT value; both should be entered in the same units (U/L).
  • A ratio of about 2 or higher is classically linked with alcoholic liver disease or advanced fibrosis, while values below 1 are common in many acute liver conditions.
  • The ratio is only meaningful alongside the actual enzyme levels and the full clinical picture — a normal ratio does not rule out liver disease.
  • Reference thresholds vary between laboratories and guidelines; treat the bands here as general orientation only.

Example: AST 45, ALT 30

Inputs
  • AST (U/L): 45
  • ALT (U/L): 30

With AST = 45 U/L and ALT = 30 U/L, the ratio is 45 ÷ 30 = 1.5, which falls in the intermediate band that may warrant further evaluation in context.

Frequently asked questions

What is the AST/ALT ratio?
It is the ratio of two liver enzymes, AST divided by ALT, also known as the De Ritis ratio. It helps characterise the pattern of liver injury.
What does a ratio above 2 suggest?
A ratio of roughly 2 or more is classically associated with alcoholic liver disease and with advanced fibrosis or cirrhosis, though it must be interpreted clinically.
What does a ratio below 1 mean?
Values under 1 are common in many acute liver conditions such as viral hepatitis or non-alcoholic fatty liver disease. It is not diagnostic on its own.
What units should I use?
Enter both AST and ALT in units per litre (U/L). Because it is a ratio, any consistent unit cancels out, but U/L is standard.
Can this replace a doctor's assessment?
No. The AST/ALT ratio is a screening aid that should be interpreted by a clinician alongside the actual enzyme values, symptoms and other tests.