AST/ALT Ratio Calculator
Calculate your AST/ALT ratio for liver health assessment. Free clinical tool with interpretation for alcoholic hepatitis, cirrhosis, and viral hepatitis screening.
About This Calculator
The AST/ALT ratio calculator (also known as the De Ritis ratio calculator) helps assess your liver health by comparing the levels of two key liver enzymes: aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT). This simple yet powerful ratio aids healthcare professionals and individuals in differentiating between various types of liver disease, including alcoholic hepatitis, cirrhosis, viral hepatitis, and non-alcoholic fatty liver disease (NAFLD).
Both AST and ALT are enzymes found within liver cells (hepatocytes). When liver cells are damaged, these enzymes leak into the bloodstream, causing elevated blood levels. The ratio of AST to ALT provides crucial diagnostic information beyond the individual enzyme values. The AST/ALT ratio is calculated by dividing the AST value by the ALT value: Ratio = AST ÷ ALT. For example, if your AST is 80 U/L and your ALT is 40 U/L, your ratio would be 2.0, which is suggestive of alcoholic liver disease.
An AST/ALT ratio greater than 2.0 is highly suggestive of alcoholic hepatitis or alcoholic liver disease. A ratio between 1.0 and 2.0 may indicate cirrhosis or advanced liver fibrosis in patients with chronic liver disease. A ratio below 0.7, particularly when both enzymes are elevated, is commonly seen in acute viral hepatitis (hepatitis B or C), non-alcoholic steatohepatitis (NASH), or drug-induced liver injury. It is important to note that a normal ratio does not rule out liver disease if the absolute enzyme levels are elevated.
The De Ritis ratio is named after the Italian physician Fernando De Ritis who first described its diagnostic value in the 1950s. Today, it remains a fundamental part of liver function assessment worldwide. The ratio should always be interpreted in the context of the complete clinical picture, including symptoms, physical examination findings, other laboratory tests (bilirubin, GGT, ALP, albumin, INR), and imaging studies.
Regional Notes
India: Liver disease is a significant health concern in India, with high prevalence of both alcoholic liver disease and viral hepatitis (particularly hepatitis B and C). The AST/ALT ratio is widely used in Indian clinical practice. Normal reference ranges may vary slightly between Indian laboratories. The Indian Council of Medical Research (ICMR) recommends routine liver function testing including AST and ALT for adults with risk factors.
United States: The American Association for the Study of Liver Diseases (AASLD) guidelines recommend the AST/ALT ratio as part of the initial evaluation for suspected liver disease. In the US, AST and ALT are typically measured in U/L with normal ranges of 10-40 U/L and 7-56 U/L respectively. The ratio is particularly useful in differentiating alcoholic liver disease from NAFLD in the American population.
United Kingdom: NICE guidelines (NG50) on cirrhosis assessment recommend using the AST/ALT ratio alongside other non-invasive markers for liver fibrosis assessment. In the UK, the ratio is commonly included in routine liver function tests available through the NHS. Primary care physicians use it as a screening tool before referring patients to hepatology specialists for further evaluation.
Frequently Asked Questions
What is the AST/ALT ratio and why is it important?
The AST/ALT ratio (also called the De Ritis ratio) is the ratio of aspartate aminotransferase (AST) to alanine aminotransferase (ALT) in your blood. It helps differentiate between different types of liver disease. A ratio greater than 2 suggests alcoholic hepatitis, a ratio between 1 and 2 may indicate cirrhosis, and a ratio below 1 with elevated enzymes suggests viral hepatitis or NAFLD. This ratio is a valuable screening tool used alongside other liver function tests.
What is a normal AST/ALT ratio?
A normal AST/ALT ratio ranges from approximately 0.7 to 1.0 in healthy adults. However, the absolute values of AST and ALT must also be within normal ranges (AST 10-40 U/L, ALT 7-56 U/L depending on the laboratory). A normal ratio with elevated enzymes may still warrant further investigation. Reference ranges may vary slightly between different laboratories and countries.
What does a high AST/ALT ratio greater than 2 mean?
An AST/ALT ratio greater than 2 strongly suggests alcoholic hepatitis or alcoholic liver disease. In alcohol-induced liver injury, AST is disproportionately elevated compared to ALT because alcohol damages mitochondrial membranes, releasing more AST. This pattern is highly specific for alcoholic liver disease when both enzymes are elevated. Your doctor may recommend liver imaging, a FibroScan, or a liver biopsy to confirm the diagnosis.
What does a low AST/ALT ratio below 0.7 mean?
An AST/ALT ratio below 0.7 with elevated liver enzymes is commonly seen in acute viral hepatitis (hepatitis B or C), non-alcoholic fatty liver disease (NAFLD), and drug-induced liver injury. In these conditions, ALT is typically higher than AST because ALT is more specific to the liver cytoplasm. Common causes include hepatitis viruses, medications like acetaminophen or statins, and metabolic conditions such as obesity and diabetes.
Which is more specific to the liver, AST or ALT?
ALT (alanine aminotransferase) is more specific to the liver than AST (aspartate aminotransferase). ALT is found primarily in the liver cytoplasm, while AST is found in the liver, heart, skeletal muscle, kidneys, and brain. This is why ALT elevation is more specific for liver injury, while AST can be elevated in other conditions such as heart attack, acute pancreatitis, or muscle diseases (myopathies).
Can the AST/ALT ratio be used to diagnose alcoholic hepatitis in India, US, and UK?
Yes, the AST/ALT ratio is used worldwide including India, the United States, and the United Kingdom as a screening tool for alcoholic liver disease. An AST/ALT ratio > 2 is considered highly suggestive of alcoholic hepatitis across all populations. However, clinicians in all countries use the ratio alongside other tests such as GGT, MCV, bilirubin, and INR for a comprehensive assessment. In the US, the ratio is often part of a routine liver panel. In India, it is particularly useful given the high prevalence of both alcoholic and viral hepatitis. In the UK, NICE guidelines recommend the AST/ALT ratio as part of the initial assessment for suspected liver disease.
What other tests should I get alongside the AST/ALT ratio?
Alongside the AST/ALT ratio, your doctor will typically order a comprehensive liver panel including bilirubin (total and direct), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), total protein, albumin, and prothrombin time/INR. For viral hepatitis screening, hepatitis B surface antigen (HBsAg) and hepatitis C antibody (anti-HCV) tests are recommended. Imaging studies like abdominal ultrasound, FibroScan, or MRI may also be ordered depending on the clinical findings.
Can medications affect my AST/ALT ratio?
Yes, many medications can affect AST and ALT levels and consequently the AST/ALT ratio. Common medications that elevate liver enzymes include acetaminophen (paracetamol) in high doses, statins, antiepileptic drugs (phenytoin, valproic acid), certain antibiotics (amoxicillin-clavulanate, isoniazid), methotrexate, and some herbal supplements. If you have elevated liver enzymes, your doctor will review your medications and may adjust dosages or switch to alternatives.