AST/ALT Ratio: What It Means When AST Is Higher Than ALT

TL;DR

• The AST/ALT ratio (also called the De Ritis ratio) is your AST divided by your ALT. In most common liver conditions, including early fatty liver and viral hepatitis, ALT is higher, so the ratio is below 1.
• In fatty liver, a ratio of 1 or more can be a sign of advanced scarring. A ratio of 2 or more is the classic pattern of alcohol-related liver disease. Muscle injury can also push AST ahead.
• The ratio is a clue, not a diagnosis. The FIB-4 score, which uses AST and ALT plus your age and platelets, is the better next step for judging scarring risk.

When AST is higher than ALT, your AST/ALT ratio is above 1. That’s worth noticing because in most common liver problems, including early fatty liver, ALT is the higher of the two; AST pulling ahead can point to alcohol, advanced scarring or a source outside the liver, such as muscle.

It’s also easy to over-read. The ratio means most when your enzymes are actually raised, and it can’t diagnose anything by itself. The checker above works out your ratio automatically when you enter both numbers. Here’s how to make sense of it.

What Does My AST/ALT Ratio Mean?

To get the ratio, divide AST by ALT. An AST of 30 and an ALT of 60 gives 0.5; an AST of 60 and an ALT of 30 gives 2.

Your AST/ALT ratio	What it means	What it can suggest
Below about 0.8	ALT clearly higher	Typical of fatty liver, especially early, and of viral hepatitis
About 0.8 to 1	The two are close	Common and non-specific on its own
1 or higher	AST equal or higher	In fatty liver, concerning for advanced scarring or another cause. Also seen in cirrhosis of any cause and with muscle injury
2 or higher	AST at least double ALT	The classic pattern of alcohol-related liver disease
Above 3	AST more than triple ALT	Makes alcohol-related liver disease even more likely
AST high, ALT normal	Ratio high, but only AST is raised	Think beyond the liver: muscle or heart

Before you look at the ratio, check each enzyme against the reference range on your own report; lab ranges differ, and your report’s range wins over any example here. A ratio is only a pattern. Your doctor will look at the trend and your other results.

What Is the AST/ALT (De Ritis) Ratio?

The ratio was first described by Fernando De Ritis in 1957, originally in viral hepatitis, where ALT tends to be higher than AST. It works because the two enzymes come from different places:

• ALT is found mainly in the liver, so it is the more specific marker of liver cell injury.
• AST is found in the liver and elsewhere, including heart muscle, skeletal muscle, kidney and brain.

So when AST rises much more than ALT, the cause is either a kind of liver injury that favors AST or a source outside the liver. For the full background on each enzyme, see our guides to the AST blood test and the ALT blood test.

Why ALT Is Usually Higher Than AST in Fatty Liver

In MASLD (metabolic dysfunction-associated steatotic liver disease, formerly NAFLD), ALT is usually the higher enzyme. A review in American Family Physician notes that people with fatty liver tend to have a ratio below 0.8, especially early in the disease, and that the ratio increases as the disease progresses to MASH with fibrosis. The ACG guideline adds that in fatty liver the levels are rarely above 300 U/L.

That’s why a ratio creeping up over time matters more than a single value. The same American Family Physician review describes a ratio above 1.0 as concerning for other causes of liver disease or for advanced fibrosis in people with fatty liver. Our pillar guide to ALT and AST levels in fatty liver covers the fatty liver picture in more depth.

What Does It Mean When AST Is Higher Than ALT?

The ACG guideline groups the causes of raised AST and ALT by which enzyme tends to lead. Conditions where AST is generally higher than ALT include:

• Alcohol-related liver disease
• Cirrhosis of any cause, although here the ratio is typically not above 2
• Reduced blood flow to the liver (ischemic hepatitis) or congestion from heart failure

Outside the liver, the ACG lists these causes of raised AST and ALT. Muscle damage in particular raises mainly AST:

• Skeletal muscle damage, including strenuous exercise and, at the extreme, rhabdomyolysis
• Heart muscle damage
• Thyroid disease
• Hemolysis (breakdown of red blood cells)
• Macro-AST, a usually harmless lab quirk
• Heat stroke

The cirrhosis effect shows up in the numbers. In one study of people with hepatitis C cited by the ACG, the average ratio was 0.60 in those without cirrhosis and 1.05 in those with it.

An AST/ALT ratio of 2 or more and alcohol

The ACG describes an AST/ALT ratio of at least 2, with AST and ALT rarely above 300 U/L, as a pattern commonly associated with alcohol-related liver disease. About 90% of people with alcohol-related liver disease have AST higher than ALT, and more than 70% have a ratio above 2. A ratio above 3 further increases the likelihood.

Part of the reason is chemistry, not just damage: people with alcohol-related liver disease often have low vitamin B6, which lowers ALT activity relative to AST. The ACG also suggests that women drinking more than 140 g of alcohol a week (about 10 US standard drinks) or men drinking more than 210 g (about 15) who have AST higher than ALT should be considered at risk for alcohol-related liver disease. A GGT test can add to the picture; see our guide to the GGT blood test.

Ratio Examples: 0.8, 1.45 and More

Here’s how the ratio plays out with some typical numbers (lab limit assumed around 33–36 U/L):

AST	ALT	Ratio	How it might be read
29	36	0.81	ALT slightly higher, both at the top of the lab range: a common pattern, worth tracking
30	62	0.48	ALT clearly leads and is raised: the usual fatty liver or viral hepatitis pattern
80	95	0.84	Both raised, ALT leading: the size of the rise matters more than the ratio
42	29	1.45	AST leads while ALT is normal: think about recent exercise or muscle, alcohol, and whether scarring is possible
120	50	2.4	AST more than double ALT: the classic alcohol pattern, which needs a doctor’s review

Notice how small numbers swing the ratio. An AST of 42 and an ALT of 29 gives 1.45, but if the ALT were 35 instead, the ratio would drop to 1.2. That’s one reason the ratio is weakest when both values are low or normal.

What If Both AST and ALT Are High?

Look at the size first, then the ratio. The ACG grades rises as borderline (under 2 times the upper limit), mild (2–5 times), moderate (5–15 times) and severe (more than 15 times). A ratio of 0.8 with both enzymes 10 times the limit is a very different situation from a ratio of 0.8 with both just over it. The ACG says moderate and severe rises need immediate evaluation, whatever the ratio.

Why the Ratio Alone Can’t Diagnose You

The ratio is a pattern, and patterns have exceptions:

• There’s no standard cutoff. A 2024 review of the De Ritis ratio notes that a standard reference range has been hard to set, because reported normal values vary widely between groups.
• It’s better at ruling out than ruling in. In the American Family Physician review, a ratio below 1.0 was useful for making advanced fibrosis less likely, but the test is less specific in people with normal ALT.
• Muscle confuses it. A hard workout can lift AST for days and make the ratio look worrying.
• Normal enzymes don’t mean a healthy liver. The AASLD notes that liver enzymes can be normal even in people with advanced liver disease from MASH.

FIB-4: The Better Next Step

Because enzymes and their ratio can’t measure scarring, the AASLD recommends the FIB-4 score as the first step for people with fatty liver or metabolic risk factors. It folds AST and ALT together with your age and platelet count:

FIB-4 = (Age × AST) ÷ (Platelets × √ALT)

• Below 1.3: low risk of advanced fibrosis (below 2.0 if you’re 65 or older)
• 1.3 to 2.67: indeterminate; a second test, such as a FibroScan, is usually next
• Above 2.67: high risk; referral to a liver specialist is usually considered

FIB-4 is unreliable under age 35. Our FIB-4 calculator walks you through finding each number on your lab report.

What to Ask Your Doctor

• Are my AST and ALT above my lab’s limits, and by how much?
• Is my ratio higher than it was before?
• Could exercise, alcohol or a medicine explain AST running higher?
• What is my FIB-4 score, and do I need a FibroScan?

If alcohol is part of the picture, read our guide on whether alcohol is safe with fatty liver.

The Bottom Line

The AST/ALT ratio is a quick pattern check. Below 1, with ALT leading, is the usual picture in early fatty liver and viral hepatitis. A ratio of 1 or more can point to advanced scarring, cirrhosis or a non-liver source, and 2 or more is the classic alcohol pattern. But the ratio can’t diagnose anything on its own, and it’s least reliable when both enzymes are normal. Look at the size of each enzyme first, ask for your FIB-4 score, and let your doctor read the whole panel.

Sources

• Kwo et al. ACG Clinical Guideline: Evaluation of Abnormal Liver Chemistries (American Journal of Gastroenterology 2017)
• Westfall et al. Nonalcoholic Fatty Liver Disease: Common Questions and Answers on Diagnosis and Management (American Family Physician 2020)
• Shaikh et al. Navigating Disease Management: A Comprehensive Review of the De Ritis Ratio in Clinical Medicine (Cureus 2024)
• AASLD Practice Guidance on the clinical assessment and management of nonalcoholic fatty liver disease (Rinella et al., Hepatology 2023)
• NIAAA: What Is a Standard Drink?

This article is for informational purposes only and is not medical advice. Talk to your doctor or hepatologist about your specific situation.