AST/ALT Ratio Calculator
The AST/ALT ratio, also known as the De Ritis ratio, is a simple calculation that helps clinicians differentiate between types of liver disease. A ratio above 2 strongly suggests alcoholic liver disease, while a ratio below 1 points toward non-alcoholic causes. Enter your AST and ALT values to calculate your ratio.
AST (aspartate aminotransferase, formerly SGOT) and ALT (alanine aminotransferase, formerly SGPT) are enzymes released into the blood when liver cells are damaged. While both are markers of liver injury, their ratio provides diagnostic clues because they have different tissue distributions and release patterns.
ALT is found primarily in the liver and is considered more specific for liver damage. AST is found in the liver, heart, muscle, kidneys, and brain. In most acute liver injuries (like viral hepatitis), ALT rises higher than AST, giving a ratio below 1.0.
Clinical patterns by ratio:
- Ratio < 1.0: Non-alcoholic fatty liver disease (NAFLD), acute viral hepatitis, drug-induced liver injury
- Ratio 1.0 to 2.0: May indicate alcoholic liver disease, advancing fibrosis, or cirrhosis from any cause
- Ratio > 2.0: Strongly suggestive of alcoholic hepatitis (classic pattern: AST usually < 300 U/L, ratio > 2, GGT elevated)
As chronic liver disease of any cause progresses to cirrhosis, the ratio tends to rise above 1.0. This happens because damaged hepatocytes release less ALT over time (ALT has a shorter half-life), and mitochondrial AST release increases with worsening cellular damage.
The De Ritis ratio was first described by Italian physician Fernando De Ritis in 1957. It remains a useful bedside tool, though it should always be interpreted alongside other liver tests (alkaline phosphatase, GGT, bilirubin, albumin), imaging, and clinical history.