AST/ALT Ratio: Normal Range, Calculator & What Results Mean

AT A GLANCE

• The AST/ALT ratio (also called the De Ritis ratio) is calculated by dividing AST by ALT — it is not directly measured in blood
• Formula: AST ÷ ALT = ratio (no units)
• Normal range: approximately 0.7–1.2 — most healthy individuals have a ratio close to 1
• Ratio > 2: classic pattern of alcoholic liver disease; also seen in muscle injury and advanced cirrhosis
• Ratio 1–2: may reflect cirrhosis, advanced fibrosis, or NASH
• Ratio < 1: most common pattern — seen in NAFLD, viral hepatitis, and acute liver injury where ALT rises more than AST
• If both AST and ALT are within normal range: the ratio is generally not clinically significant regardless of its value
• Normal ranges and clinical cutoffs vary by laboratory and clinical context. Interpret alongside absolute enzyme levels, GGT, and symptoms.

QUICK REFERENCE

AST/ALT Ratio — Interpretation

< 0.7           =  Low — ALT significantly > AST. Typical of NAFLD, acute viral hepatitis.
0.7–1.0       =  Normal-low — most healthy individuals and NAFLD pattern.
1.0–1.2       =  Normal — healthy range, AST and ALT roughly equal.
1.2–2.0       =  Mildly elevated — possible cirrhosis, NASH, early fibrosis.
> 2.0           =  High — AST dominant. Classic alcoholic liver disease pattern.
> 3.0           =  Very high — strongly suggestive of alcoholic hepatitis when GGT also elevated.

Formula: AST ÷ ALT = ratio   |   Example: AST 48 ÷ ALT 32 = 1.5

WHAT TO DO NEXT

Based on your ratio and absolute enzyme levels:

• Ratio 0.7–1.2, both enzymes within normal range — No action needed. The ratio is not clinically meaningful when both enzymes are normal.
• Ratio < 0.7, elevated enzymes — Pattern consistent with NAFLD, viral hepatitis, or acute liver injury. Discuss with your doctor for further evaluation including hepatitis testing and imaging if indicated.
• Ratio 1.2–2.0, elevated enzymes — Warrants clinical evaluation. Possible cirrhosis, NASH, or progressive liver disease. Your doctor may order additional liver function tests, imaging, or fibroscan.
• Ratio > 2.0, elevated enzymes — Discuss with your doctor promptly. Pattern associated with alcoholic liver disease or muscle injury. GGT level is important context — a high GGT alongside ratio > 2 strengthens the alcoholic liver disease pattern. If no alcohol use, rule out muscle injury (check CK).
• Ratio > 2.0, normal absolute enzymes — Low clinical concern. The ratio is not meaningful when both enzymes are within normal limits.
• Any ratio with fever, jaundice, abdominal pain, or symptoms — Seek prompt medical evaluation.

WHAT IS THE AST/ALT RATIO?

The AST/ALT ratio — also known as the De Ritis ratio — compares two liver enzymes: aspartate aminotransferase (AST) and alanine aminotransferase (ALT). It is not a separate blood test; it is calculated from your individual AST and ALT results on a comprehensive metabolic panel (CMP) or liver function panel.

Formula: AST ÷ ALT = ratio

Both AST and ALT are released into the bloodstream when liver cells are damaged. Because the two enzymes have different distributions in the body and respond differently to different types of liver injury, their ratio provides information about the likely cause and pattern of damage that neither enzyme provides alone.

ALT is more liver-specific — it is found predominantly in the liver. AST is found in the liver but also in muscle, the heart, kidneys, and brain. This lower specificity of AST means a high AST does not always mean liver disease — muscle injury, heart attack, and intense exercise can all raise AST without any liver involvement.

The ratio is most useful as a pattern-recognition tool when at least one enzyme is elevated. When both AST and ALT are within normal limits, a ratio above or below 1 has no established clinical significance.

HOW TO READ YOUR RESULT

These cutoffs are clinical guides, not diagnostic thresholds. Always interpret alongside individual AST and ALT levels, GGT, symptoms, and clinical history.

COMMON PHRASES SEEN ON LAB REPORTS

AST/ALT RATIO
AST ALT RATIO
AST:ALT RATIO
ALT/AST RATIO
ALT:AST RATIO
AST TO ALT RATIO
ALT TO AST RATIO
AST OVER ALT
DE RITIS RATIO
DE RITIS QUOTIENT
SGOT/SGPT RATIO
SGPT/SGOT RATIO
ASAT/ALAT RATIO
ASAT ALAT KVOT (SWEDISH)
STOSUNEK ALT DO AST (POLISH)
RELACIÓN AST/ALT (SPANISH)
RATIO DE RITIS (FRENCH)
СООТНОШЕНИЕ АЛТ И АСТ (RUSSIAN)
AST/ALT RATIO BIOMARKER TEST
AST:ALT RATIO BIOMARKER TEST

All of these refer to the same calculated value: AST divided by ALT. The De Ritis ratio and SGOT/SGPT ratio are older names for the same calculation — SGOT is another name for AST and SGPT is another name for ALT.

DOES THE AST/ALT RATIO MATTER IF BOTH ENZYMES ARE NORMAL?

No — and this is the most commonly misunderstood aspect of this ratio. Many online calculators produce alarming-looking ratios from perfectly normal enzyme values. A ratio of 1.6 with AST of 18 U/L and ALT of 11 U/L — both well within normal — has no established clinical significance.

The De Ritis ratio is a pattern-recognition tool for abnormal enzyme elevations. It was developed to help distinguish the cause of elevated liver enzymes, not to detect liver disease from normal values. When both AST and ALT are in range, the ratio cannot tell you anything meaningful about liver health.

If you calculated your ratio from normal absolute values and found a ratio above 1.2 or 2.0, this does not require follow-up. The ratio is only interpretable when at least one enzyme is elevated.

WHAT DOES A RATIO ABOVE 2 MEAN?

A ratio above 2 is the classic pattern of alcoholic liver disease (ALD). The mechanism is specific: alcohol preferentially damages mitochondria, which contain high concentrations of AST, and depletes pyridoxine (vitamin B6), which is required for ALT synthesis — so AST rises substantially more than ALT.

When the ratio is above 2 alongside elevated GGT, the alcoholic liver disease pattern is particularly strong. GGT is also elevated by alcohol use and is a sensitive marker of chronic alcohol exposure.

Other causes of AST/ALT ratio > 2:

• Muscle injury — rhabdomyolysis, myopathy, intense exercise, and myocardial infarction raise AST from non-liver sources without liver involvement. If alcohol use is absent, muscle injury should be ruled out (check creatine kinase, CK).
• Advanced cirrhosis from any cause — as liver function deteriorates, hepatocytes are lost and ALT production falls more than AST, raising the ratio regardless of the original cause.
• Wilson's disease — rare copper metabolism disorder; can produce high ratio.
• Thyroid disease — thyroid dysfunction occasionally affects liver enzyme ratios.

A ratio above 2 with normal absolute AST and ALT does not confirm liver disease. The absolute values matter as much as the ratio.

WHAT DOES A RATIO BELOW 1 MEAN?

A ratio below 1 means ALT is higher than AST — the more common pattern in most liver conditions. Because ALT is more liver-specific, acute hepatocellular damage tends to raise ALT preferentially.

Causes of AST/ALT ratio < 1:

• Non-alcoholic fatty liver disease (NAFLD) — the most common cause of a chronically low ratio in developed countries. NAFLD typically shows ALT mildly elevated with AST below or equal to ALT.
• Acute viral hepatitis (A, B, C) — the acute phase characteristically shows markedly elevated ALT with a ratio well below 1. As disease progresses toward cirrhosis, the ratio rises.
• Drug-induced liver injury — most hepatotoxic medications cause ALT-dominant patterns.
• Acute liver injury from any cause — early or acute damage to liver cells typically raises ALT more than AST.

AST VS ALT: WHY DOES THE RATIO MATTER?

Because AST comes from multiple tissues, a high AST alongside a normal ALT may indicate muscle injury rather than liver disease. The ratio helps distinguish liver-specific patterns from multi-tissue patterns.

RELATED TESTS AND NEXT STEPS

When the AST/ALT ratio is elevated alongside elevated enzymes, the following tests provide important additional context:

• GGT (Gamma-Glutamyl Transferase) — elevated GGT alongside ratio > 2 strongly supports alcoholic liver disease pattern; GGT is also a sensitive marker of chronic alcohol use
• Alkaline Phosphatase (ALP) — elevated ALP alongside liver enzymes suggests biliary obstruction or bone disease
• Bilirubin, Total — elevated bilirubin indicates impaired liver excretion; raises concern for more significant liver dysfunction
• Albumin — low albumin indicates reduced synthetic function; marker of advanced liver disease
• Creatine Kinase (CK) — if ratio > 2 without alcohol use, elevated CK points to muscle injury as the source of high AST
• Hepatitis B and C testing — if ratio < 1 with elevated enzymes and no obvious cause
• Liver ultrasound — first-line imaging for fatty liver, cirrhosis, or structural abnormalities

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