Blood Test

AST:ALT Ratio (De Ritis Ratio)

Name: AST/ALT Ratio: Normal Range & Liver Disease Pattern
Creator: Suman Konda
Published: 2026-07-05

The ratio of AST to ALT (the De Ritis ratio) is a simple calculation from your liver blood test that helps identify the likely cause of liver damage. An AST:ALT ratio above 2 strongly suggests alcoholic liver disease.

Written and clinically reviewed by Suman Konda, PharmD, Clinical Pharmacist · Based on peer-reviewed sources · Editorial policy · Not medical advice

Last reviewed and updated: 01 August 2026 · How we check our content

What is the AST:ALT ratio?

AST (aspartate aminotransferase, also called SGOT) and ALT (alanine aminotransferase, also called SGPT) are liver enzymes measured in every liver function test. While both rise when liver cells are damaged, they rise to different degrees depending on the cause. The AST:ALT ratio, also called the De Ritis ratio, is calculated by dividing the AST value by the ALT value. The pattern of which enzyme rises more provides a diagnostic clue to the underlying cause of liver damage.

AST:ALT ratio interpretation

Ratio	Pattern	Likely diagnosis
< 1 (ALT > AST)	ALT dominant	Viral hepatitis (A, B, C), NAFLD/fatty liver, drug-induced liver injury
1:1	Equal rise	Non-specific: less diagnostic value
> 2:1 (AST 2x ALT)	AST dominant	Alcoholic liver disease (classic pattern)
> 3:1	Strongly AST dominant	Alcoholic hepatitis or cirrhosis; consider Wilson disease
Very high ALT (10x+), any ratio	Massive elevation	Acute viral hepatitis, ischaemic hepatitis, drug toxicity

Why is AST:ALT >2 typical of alcoholic liver disease?

In alcoholic liver disease, alcohol and its metabolite acetaldehyde directly damage mitochondria (where AST is concentrated in liver cells), causing disproportionate AST release. Simultaneously, alcohol depletes pyridoxal-5-phosphate (vitamin B6), which is required for ALT synthesis: so ALT levels are relatively suppressed. This two-part mechanism explains why AST rises more than ALT in alcoholic liver injury.

Why is ALT higher than AST in viral hepatitis and fatty liver?

In viral hepatitis and NAFLD, hepatocyte cell membrane damage is the primary mechanism, and ALT is predominantly cytoplasmic (released easily through the damaged membrane). ALT is also more specific to the liver than AST (which also comes from heart, muscle and other tissues). So in non-alcoholic liver disease, ALT is the more sensitive and more elevated marker.

Other tests to interpret alongside the ratio

Test	Why it matters
GGT	Very high in alcoholic liver disease; supports AST:ALT >2 pattern
MCV (mean cell volume)	High MCV (macrocytosis) is common with alcohol excess
Bilirubin	Indicates severity of liver dysfunction
Albumin / INR	Liver synthetic function: low = serious

Questions to ask your doctor

What is likely causing my liver enzyme elevation?
Do I need a hepatitis B and C test?
Should I have a liver ultrasound?
Is alcohol use contributing to my liver results?
Do I need a liver biopsy?

References

The clinical information on this page is drawn from peer-reviewed sources indexed by the US National Library of Medicine. Links go to the source so you can read it yourself.

Liver Function Tests. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK482489
Hepatic Cirrhosis. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK482419