AST ALT Ratio Calculator

The AST ALT ratio divides the blood concentration of aspartate aminotransferase by alanine aminotransferase. It is also known as the De Ritis ratio. Both enzymes can rise when cells are injured, but they are distributed differently in the body. ALT is relatively concentrated in the liver, whereas AST is also found in skeletal muscle, heart, red blood cells, and other tissues. The ratio therefore adds pattern information to the individual enzyme values but cannot identify a diagnosis by itself. A ratio below 1 means ALT exceeds AST. This pattern is often discussed in relation to acute viral hepatitis and metabolic dysfunction-associated steatotic liver disease, but it is not specific and may also appear in healthy results. Ratios between 1 and 2 have many possible explanations. A ratio above 2 is classically associated with alcohol-related liver injury when the enzymes are elevated, yet muscle injury, advanced fibrosis, hemolysis, and other conditions can also increase AST relative to ALT. Very high aminotransferases require attention regardless of the ratio. The calculation is meaningful only when both tests come from the same sample and use the same units. A normal-looking ratio does not make abnormal AST or ALT concentrations normal. Conversely, dividing two values within their laboratory reference intervals can produce a high or low ratio without evidence of disease. Reference ranges vary with assay, laboratory, sex, age, body composition, medications, exercise, and other factors. Recent strenuous exercise can raise AST, and supplements or prescription medicines can affect either enzyme. Clinicians interpret the pattern alongside bilirubin, alkaline phosphatase, gamma-glutamyl transferase, albumin, clotting tests, symptoms, alcohol history, metabolic risk, viral testing, and imaging when appropriate. The ratio is not a screening verdict for alcohol use and should never be used to label a person. Seek medical advice for unexplained abnormal liver tests, jaundice, dark urine, severe abdominal symptoms, confusion, or bleeding. This calculator performs arithmetic for education and discussion; it does not replace laboratory interpretation or medical evaluation.