Ast Alt Ratio Calculator

Divide AST by ALT to find the De Ritis ratio from your liver enzyme results, with a band interpretation of the pattern.

Quick Facts

Formula
De Ritis ratio = AST divided by ALT (both in U/L)
The result is unitless because both enzymes use the same units.
Rule of thumb
Under 1, between 1 and 2, or 2 and above
A ratio of 2 or more is classically linked to alcoholic liver disease; interpret with a clinician.

Your Results

Calculated
AST/ALT ratio
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De Ritis ratio (AST divided by ALT)
Category
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Ratio band
ALT/AST ratio
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Reciprocal (inverse) ratio
Typical pattern
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General association

Ready

Enter your AST and ALT values, then press Calculate.

About the AST/ALT ratio

The AST/ALT ratio, also called the De Ritis ratio, compares two liver enzymes measured on a routine blood panel: aspartate aminotransferase (AST) and alanine aminotransferase (ALT). The calculation is simply AST divided by ALT, with both values in the same units (usually U/L). Because the units cancel, the ratio itself is a plain number. It was first described by Fernando De Ritis in 1957 and remains a quick way to characterize the pattern of a liver enzyme elevation.

The formula and how to read the bands

Enter your AST and ALT values exactly as they appear on your lab report and the calculator returns AST divided by ALT. The result usually falls into one of three commonly cited bands:

  • Under 1: typical of a healthy liver and of acute hepatocellular injury such as acute viral hepatitis, drug-induced injury, or non-alcoholic fatty liver disease before significant scarring.
  • Between 1 and 2: can accompany chronic liver disease, advancing fibrosis, or cirrhosis; a rising ratio in non-alcoholic fatty liver disease may signal more advanced fibrosis.
  • 2 or above: classically associated with alcoholic liver disease, often alongside a raised gamma-glutamyl transferase (GGT).

Putting the result in context

The ratio is most informative when at least one enzyme is elevated; comparing two normal values tells you little. Reference ranges vary by laboratory, sex, and assay, so always read AST and ALT against the ranges printed on your own report. The bands describe patterns, not diagnoses — the same ratio can arise from very different causes, and a single blood draw is only a snapshot.

When to consult a professional

The AST/ALT ratio is a screening pattern, not a diagnosis. For any abnormal enzyme level or a ratio that concerns you, and for any decision that affects medical treatment, consult a licensed healthcare provider who can interpret the numbers alongside your history, symptoms, and other tests.

Frequently Asked Questions

How is the AST/ALT ratio calculated?
Divide the AST (aspartate aminotransferase) value by the ALT (alanine aminotransferase) value, using the same units for both (usually U/L). For example, an AST of 40 U/L and an ALT of 20 U/L give a ratio of 2.0. Because both enzymes share the same units, the ratio itself has no units. It is also known as the De Ritis ratio.
What does an AST/ALT ratio above 2 mean?
A ratio of 2 or higher is classically associated with alcoholic liver disease, often together with a raised GGT. A ratio under 1 is typical of a healthy liver or of acute hepatocellular injury such as viral hepatitis and non-alcoholic fatty liver disease, while a ratio between 1 and 2 can accompany chronic liver disease, fibrosis, or cirrhosis. The ratio describes a pattern, not a diagnosis, and should be interpreted by a healthcare provider alongside your full results.
What are normal AST and ALT levels?
Reference ranges vary by laboratory, sex, and assay, but AST is often roughly 8 to 33 U/L and ALT roughly 7 to 56 U/L. The AST/ALT ratio is most informative when at least one enzyme is elevated; comparing the two enzymes only makes sense against your own lab's reference ranges. Discuss any abnormal values with a healthcare provider.

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