On This Page – Quick Medical Summary
What your AST/ALT ratio is (and isn’t)
Your lab report lists AST and ALT side by side, and one may be flagged. The AST/ALT ratio compares the two to help your doctor narrow down causes. It’s also called the De Ritis ratio, after the researcher who first described it in 1957. On its own, it diagnoses nothing.
Start where your situation fits:
- AST higher than ALT and worried about alcohol: see the section on drinking below.
- ALT higher than AST: go to the pattern table.
- Numbers far above normal: jump to the urgent-attention section.
Everyone else can read straight through. If you want the single-number view first, here’s what your ALT number means on its own.
ℹ️ Medical Disclaimer: This article explains lab results for general education. It does not diagnose liver disease, recommend treatment or medication changes, or replace emergency care. Review your results with your primary care physician before acting, and with a gastroenterologist or hepatologist if you’ve been referred to one.
Why AST and ALT tell different stories
Both enzymes leak into your blood when cells are damaged, but they come from different tissues.
Where each enzyme comes from
ALT (older name: SGPT) is concentrated in the liver, which makes it the more liver-specific marker. AST is found in the liver but also in the brain, heart, and skeletal muscle. The MedlinePlus explainer on the AST test notes AST’s older name, SGOT.
🔬 How It Works: When cells are injured, their enzymes spill into the bloodstream. Liver injury tends to raise both enzymes. Muscle damage can raise AST even when the liver isn’t the source, and that shifts the ratio.
How the ratio is calculated
Divide your AST result by your ALT result. For example, an AST of 60 and an ALT of 30 gives a ratio of 2.0 (these are example numbers only). There’s no standardized “normal” ratio, and published reference values vary widely.
What a ratio below 1, near 1, or above 2 can suggest
The American College of Gastroenterology associates a ratio of at least 2:1 with alcohol-related liver injury. In that pattern, AST and ALT rarely go above 300 IU/L.
| Pattern | What it can suggest | Key Clinical Detail | What it does NOT prove |
|---|---|---|---|
| ALT higher than AST (below 1) | Fatty liver disease (MASLD, formerly NAFLD) | Levels rarely exceed 300 IU/L | That your liver is healthy or unhealthy |
| AST rising toward or above ALT | Advancing scarring, or a non-liver AST source | The ratio tends to climb at the scarring stage | Cirrhosis, which other tests must confirm |
| AST 2× ALT or more | Alcohol-related liver injury | AST and ALT rarely above 300 IU/L | Heavy drinking on its own (see next section) |
Sources: ACG Clinical Guideline (2017); De Ritis ratio review, PMC (2024).
When ALT runs higher than AST
Fatty liver disease has no unique pattern, but ALT is generally higher than AST. The American College of Gastroenterology’s guideline on abnormal liver tests describes this pattern.
When AST is double ALT or more
This is the classic alcohol-related pattern, but it’s strongest in advanced disease, as the next section shows.
Why the ratio can rise as scarring advances
Early fatty liver disease can keep the ratio low. At the scarring stage the ratio tends to rise, because damaged cells release AST from their mitochondria.
A high ratio doesn’t automatically mean heavy drinking
A 2:1 ratio can feel like an accusation, but the evidence is more nuanced than that.
What the research on drinkers actually shows
A 2004 Swedish study compared AST/ALT ratios across three groups of hospital patients with heavy alcohol use.
📊 Clinical Data Point: Among patients admitted for alcohol withdrawal, 64% had a ratio of 1.0 or lower, and a ratio of 2 or more was rare. Among patients with alcohol-related cirrhosis, 69% had a ratio of 2 or more. Source: Nyblom et al., Alcohol and Alcoholism, 2004.
The authors concluded that a high ratio points more toward advanced alcohol-related liver disease than toward heavy drinking itself. This was one study of hospitalized patients, so it shows a pattern, not a rule for every reader.
Non-liver reasons AST can run high
AST is also found in skeletal muscle and heart tissue. Damage there can raise AST, and with it the ratio, even when the liver is not the source.
✅ Patient Action: Before your follow-up, note any recent muscle injury. Ask your primary care physician: “Could a non-liver source explain my AST?”
The other numbers your doctor reads alongside the ratio
Your doctor reads the ratio together with how high each enzyme is and, often, a liver scarring score.
How high is “high”: the ACG severity bands
ACG grades AST and ALT elevations against the upper limit of normal (ULN) for your lab:
- Borderline: under 2× ULN
- Mild: 2–5× ULN
- Moderate: 5–15× ULN
- Severe: over 15× ULN
ACG puts a truly healthy ALT at 29–33 IU/L for men and 19–25 IU/L for women. Our guide to healthy ALT ranges goes further.
FIB-4: where AST and ALT feed a scarring score
The FIB-4 index combines your age, AST, ALT, and platelet count. AASLD’s fatty liver practice guidance calls for a second test, such as elastography, at a score of 1.3 or more. Above 2.67, specialist referral becomes more likely. The guidance uses a cutoff above 2.0 after age 65 and notes the score is less accurate under 35.
People with type 2 diabetes, prediabetes, or two or more metabolic risk factors may be rechecked more often. One such risk factor is a higher BMI, which you can check with our BMI calculator.
What to ask your doctor about an abnormal ratio
An abnormal ratio usually leads to a structured workup rather than a single answer.
Tests commonly ordered next
ACG’s evaluation of hepatocellular injury includes testing or assessment for:
- Viral hepatitis A, B, and C
- Fatty liver disease and alcohol-related liver disease
- Hereditary hemochromatosis
- Autoimmune hepatitis, Wilson’s disease, and alpha-1 antitrypsin deficiency
For the conditions behind these tests, see common reasons ALT runs high.
What to tell your doctor up front
ACG says people with AST above ALT should be considered at risk for alcohol-related liver disease if they drink more than 140 g of alcohol a week (women) or 210 g (men). A US standard drink holds 14 g, so that’s roughly 10 or 15 drinks a week. Also list every prescription, over-the-counter medicine, and supplement you take.
✅ Patient Action: Ask your primary care physician: “Which causes have we ruled out, and do my results warrant a gastroenterologist or hepatologist?”
When liver test results need urgent attention
Most abnormal ratios lead to a routine follow-up, but a few situations can’t wait.
Very high enzyme levels
ACG advises checking for acetaminophen toxicity and ischemic liver injury (“shock liver”) in two situations. The first is AST or ALT above 15 times the upper limit of normal. The second is ALT above 10,000 IU/L. Our guide to what causes an ALT above 1,000 explains these patterns.
Symptoms that shouldn’t wait
⚠️ Clinical Warning: ACG recommends immediate referral to a liver specialist when acute hepatitis comes with abnormal blood clotting or encephalopathy (confusion caused by liver dysfunction). If abnormal liver results come with new confusion, yellowing skin or eyes, dark urine, or pale stools, contact your doctor the same day rather than waiting for a routine appointment.
AST/ALT ratio: frequently asked questions
1. What is a normal AST/ALT ratio?
There’s no standardized normal AST/ALT ratio. Published reference values vary widely, so doctors read it alongside your actual AST and ALT levels.
2. What does it mean if AST is higher than ALT?
An AST/ALT ratio above 1 can reflect alcohol-related injury, advancing scarring, or a non-liver AST source like muscle. Ask your primary care physician which fits.
3. Does a high AST/ALT ratio mean I drink too much?
Not necessarily. In one study, most heavy drinkers without severe liver disease had an AST/ALT ratio at or below 1. Share your intake honestly.
4. Can muscle injury raise AST?
Yes. AST sits in skeletal muscle and heart tissue, so muscle damage can raise AST, and the AST/ALT ratio, even when the liver isn’t the source.
5. What AST/ALT ratio is typical of fatty liver?
With fatty liver disease, ALT is usually higher than AST, giving an AST/ALT ratio below 1. The ratio can climb as scarring develops.
6. Does a high AST/ALT ratio mean cirrhosis?
Not on its own. A rising AST/ALT ratio can accompany advanced scarring, so ask your physician which tests would confirm or rule out cirrhosis.
7. What is FIB-4?
FIB-4 goes beyond the AST/ALT ratio by combining age, AST, ALT, and platelet count. AASLD advises a second test at a score of 1.3 or higher.
8. What tests follow an abnormal AST/ALT ratio?
Doctors often check for viral hepatitis, fatty liver, alcohol-related disease, hemochromatosis, and autoimmune or inherited liver conditions. Ask which apply to you.
9. Are SGOT and SGPT the same as AST and ALT?
Yes. SGOT is AST’s older name and SGPT is ALT’s, so an SGOT/SGPT ratio is the same as the AST/ALT ratio.
10. When are liver enzymes dangerously high?
Whatever your AST/ALT ratio, ACG advises urgent evaluation when AST or ALT exceeds 15 times the upper limit of normal. Seek care promptly.
11. Can supplements affect liver enzymes?
They can, so ACG advises doctors to ask about medications and supplements when interpreting liver enzymes and the AST/ALT ratio. Bring a complete list.
Your next step
Your AST/ALT ratio is a clue that points your doctor toward likely causes. It is not a verdict on your liver or your habits. Bring your full lab report, an honest account of your alcohol intake, and a list of every medication and supplement to your follow-up. That appointment is where the ratio becomes an answer.
About this content
How this article was put together: researched from recognised health sources, drafted with the help of AI tools, and edited by hand, with sources linked throughout.
Sameer Patel is the founder and editor of My Medicine Advisor. He is not a doctor or medical professional — before starting this site he worked in banking,…
Medical disclaimer
The content on MyMedicineAdvisor is provided for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Health information on this website should not be used to diagnose, treat, cure, or prevent any condition without guidance from a qualified healthcare professional. Always seek the advice of your doctor, physician, or another licensed healthcare provider with any questions you may have regarding a medical condition, symptoms, medications, or treatment decisions.
