AST/ALT Ratio Calculator — De Ritis Ratio for Liver Disease
The AST/ALT ratio (also called the De Ritis ratio) is a simple blood-test calculation used to distinguish possible causes of liver enzyme elevation. Enter your AST and ALT values in U/L to get the ratio and a pattern-based interpretation.
U/L
U/L
Ratio ≥ 2: strongly associated with alcoholic liver disease (De Ritis criterion)
- 1
AST level
60 U/L - 2
ALT level
30 U/L - 3
AST ÷ ALT ratio
60 ÷ 30 = 2A ratio ≥ 2 meets the De Ritis criterion associated with alcoholic liver disease.
How does this calculator work?
AST/ALT ratio = AST ÷ ALT. A ratio < 1 suggests viral hepatitis or NAFLD; a ratio ≥ 2 (the De Ritis criterion) suggests alcoholic liver disease. Values between 1 and 2 are non-specific. Always confirm with clinical evaluation — this is a screening tool only.
Formula
How this is calculated
AST (aspartate aminotransferase, sometimes labelled SGOT) and ALT (alanine aminotransferase, sometimes labelled SGPT) are enzymes released into the blood when liver cells are damaged. ALT is more liver-specific; AST is also found in cardiac and skeletal muscle. The De Ritis ratio, first described in 1957, exploits the fact that the two enzymes are elevated in different proportions depending on the underlying cause of liver injury.
A ratio below 1.0 (ALT dominant) is characteristic of viral hepatitis (hepatitis B, C) and non-alcoholic fatty liver disease (NAFLD), where hepatocyte damage preferentially releases ALT. A ratio at or above 2.0 is strongly associated with alcoholic liver disease, because alcohol causes mitochondrial damage that disproportionately elevates AST; an AST/ALT ratio ≥ 2 combined with an AST > 50 U/L and AST < 500 U/L is a classic teaching criterion for alcoholic hepatitis. Ratios between 1 and 2 are non-specific and require clinical correlation.
Important limitations: the ratio is a screening aid, not a diagnostic test. Many factors confound both values — haemolysis, intense exercise, cardiac events, and certain medications all raise AST. ALT can be falsely low in haemodialysis patients and in severe malnutrition. Reference ranges vary by laboratory and sex. Always interpret the ratio alongside absolute enzyme levels, clinical history, imaging, and specialist assessment.
Frequently asked questions
In healthy individuals both AST and ALT are within the laboratory reference range (roughly 10–40 U/L, though this varies by lab and sex), and the ratio is usually close to 1 or slightly below. A ratio consistently above 2 is considered abnormal and suggests an AST-dominant pattern.
No. An AST/ALT ratio ≥ 2 is associated with alcoholic liver disease but is not specific to it. Cirrhosis from any cause, cardiac muscle injury (AST is present in heart muscle), and non-hepatic conditions can all produce a ratio above 2. Clinical context is essential.
The De Ritis ratio is another name for the AST/ALT ratio, named after Fernando De Ritis who described its diagnostic utility in liver disease in 1957. The threshold of 2 for distinguishing alcoholic from viral hepatitis remains widely used in clinical teaching.
Also known as
TG we-Calculate Editorial Team. (2026). AST/ALT Ratio Calculator — De Ritis Ratio for Liver Disease [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/ast-alt-ratio-calculator
TG we-Calculate Editorial Team. "AST/ALT Ratio Calculator — De Ritis Ratio for Liver Disease." TG we-Calculate. 2026. https://we-calculate.com/calculator/ast-alt-ratio-calculator.
TG we-Calculate Editorial Team, "AST/ALT Ratio Calculator — De Ritis Ratio for Liver Disease," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/ast-alt-ratio-calculator
@misc{wecalculate_ast_alt_ratio_calculator, title = {AST/ALT Ratio Calculator — De Ritis Ratio for Liver Disease}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/ast-alt-ratio-calculator}}, year = {2026}, note = {TG we-Calculate} }
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