# AST: A liver enzyme that muscle makes too

> AST comes from your liver, muscles and heart. Check your result, see what AST higher than ALT means, and what to do if yours is high.

- Also called Aspartate aminotransferase, SGOT and AST (SGOT)
- Often on a standard checkup
- Fast for 12 hours
- Web page: https://picardo.health/guides/biomarkers/ast

## The short answer

AST is an enzyme in your liver, muscles and heart, and it leaks into your blood when any of them is damaged. Labcorp’s range is 0 to 40 IU/L. If yours is higher, your ALT usually shows where it’s coming from.[1][9]

- **A good result:** 40 IU/L or under.[9]
- **If yours is high:** Compare it with ALT. AST well above ALT often points to alcohol or muscle, and ALT above AST to the liver. Hard exercise can raise both for a week or more.[1][3]
- **Should you test?** It’s on most checkup blood tests. It’s also part of the FIB-4 score that checks for liver scarring.[5]

## What is a normal AST level?

Labcorp’s range for AST is 0 to 40 IU/L.[9] What a raised result means depends a lot on your ALT:[1]

| Result (IU/L) | What it means |
| --- | --- |
| Under 41 | In the normal range |
| 41 to 199 | Raised: look at your ALT |
| 200 or more | High: see a clinician promptly |

### In the normal range

**Range:** 40 IU/L or under.

Your AST is within Labcorp’s range.[9] If your ALT is normal too, your liver cells aren’t showing obvious strain. Normal enzymes can still hide scarring from fatty liver, though.[5]

**How worried to be:** Nothing to worry about.

**What to do next:**

1. If you have type 2 diabetes, prediabetes or extra weight with other metabolic risks, a FIB-4 score uses your AST and ALT to check for scarring.[5]

[Test FIB-4, $28.87](https://app.picardo.health/labs/order?tests=403604&ref=guide-ast)

### Raised: look at your ALT

**Range:** 41 to 199 IU/L.

Your AST is above the lab’s range, by less than 5 times its upper limit.[1][9] Check the ALT on the same report. If only AST is up, muscle is a likely source, especially after hard exercise.[1][3] If AST is at least twice ALT, alcohol is a common cause.[1]

**How worried to be:** Not an emergency. Worth finding the cause in the next few weeks.

**What to do next:**

1. If you trained hard in the two weeks before your test, retest after at least a week, and ideally two, without heavy exercise.[3]
2. If your ALT is raised too, test for hepatitis B and C, and check your iron.[1]
3. If you drink, stop while you find the cause.[1]

[Test hepatitis B and C, iron and ferritin, $30.75](https://app.picardo.health/labs/order?tests=006510,144050,001321,004598&ref=guide-ast)

### High: see a clinician promptly

**Range:** 200 IU/L or more.

That’s at least 5 times the upper limit, and guidelines say it calls for tests for acute hepatitis as well as the usual causes.[1] Causes include viral hepatitis, alcohol, a reaction to a medicine, poor blood flow to the liver and muscle breakdown after an injury or extreme exercise.[1][3]

**How worried to be:** See a clinician within a day or two. Get emergency care now if you’re confused or very drowsy. Get care today if your skin or the whites of your eyes turn yellow.[1]

**What to do next:**

1. Take this result to a clinician, with your ALT and a list of every medicine and supplement you take.[1]
2. Mention any hard exercise or muscle injury in the past two weeks.[3] A CK blood test can check for muscle damage.[1]

## What is AST?

> If ALT is a smoke alarm in the liver, AST is one wired to the whole building. It goes off for the liver, but also for muscle and the heart.

AST, short for aspartate aminotransferase, is an enzyme in liver cells, and also in skeletal muscle, heart muscle, kidneys and brain.[1] So a raised AST doesn’t always mean the liver. ALT, which comes mostly from the liver, helps sort it out.[1]

## Why is my AST higher than my ALT?

Which of the two is higher is a clue to the cause:[1][2]

| What your report shows | A common reason |
| --- | --- |
| AST at least twice ALT | Alcohol-related liver disease |
| AST higher than ALT, with other signs of liver disease | Cirrhosis, from any cause |
| AST raised, ALT normal | Often muscle or heart, but heavy drinking can do this too |
| ALT higher than AST | Fatty liver, viral hepatitis or medicines |

These are clues, not diagnoses.[1][2]

## Can exercise raise AST?

Yes, by a lot. In one study, 14 healthy young men who didn’t usually lift weights did one hour of weightlifting. Their AST peaked about 4 days later, at up to about 23 times the upper limit, and stayed raised for at least a week. ALT rose too, and was still raised in most of the men 10 to 12 days later, while GGT, ALP and bilirubin barely changed.[3]

The researchers advise no weightlifting for at least a week before liver tests in drug trials.[3] If you train hard, mention it to whoever reads your result.

## What raises AST?

- Alcohol[1][4]
- Fatty liver, though there ALT is usually the higher of the two[1]
- Muscle injury, hard exercise and muscle diseases[1][3]
- Hepatitis B and C, and medicines or supplements that injure the liver[1]
- Damage to heart muscle[1]
- Less often, thyroid disease, red blood cells breaking down and a lab quirk called macro-AST[1]

## How to lower AST

- **Stopping or cutting back on alcohol:** Heavy drinking often pushes AST above ALT.[1] Fatty liver from alcohol reverses when you stop.[4] How much it helps: a lot. How sure we are: very sure.
- **Losing weight, if you have fatty liver:** Losing 3% to 5% of your weight reduces liver fat. Reversing scarring usually takes 10% or more.[5] How much it helps: some. How sure we are: very sure.
- **One to two weeks off heavy exercise before you retest:** After hard weightlifting, AST can stay raised for at least a week, and ALT for 10 days or more.[3] How much it helps: some. How sure we are: fairly sure.
- **Reviewing medicines and supplements:** Some prescription drugs and herbal supplements can injure the liver. Ask before stopping a prescribed medicine.[1] How much it helps: some. How sure we are: fairly sure.

## Who should get an AST test?

AST comes on the comprehensive metabolic panel, alongside ALT. It matters most if:

- You drink alcohol regularly. Heavy drinking often pushes AST above ALT.[1]
- You have type 2 diabetes or prediabetes, or extra weight along with another metabolic risk such as high blood pressure. AST goes into the FIB-4 score for liver scarring.[5]
- You take medicines or supplements that can affect the liver.[1]

Whatever your liver tests show, every adult should be tested for hepatitis B and C at least once.[7][8]

## How to get an AST test, and what it costs

It comes from the comprehensive metabolic panel, which costs $4.00 through Picardo. The Heart Health panel adds 16 more tests from the same visit for $150.90.

- **Recommended:** [the Heart Health panel, $150.90](https://app.picardo.health/labs/order?panels=heart-health&ref=guide-ast). 17 tests, fast for 12 hours first. AST is one clue. The panel adds GGT, which helps when alcohol is a question, and a platelet count for a FIB-4 scarring score, plus the blood sugar and cholesterol tests that go with fatty liver. [What’s in it](https://picardo.health/guides/panels/heart-health.md).
- [Comprehensive metabolic panel, $4.00](https://app.picardo.health/labs/order?tests=322000&ref=guide-ast). The test this number comes from. Labcorp 322000, fast for 12 hours.

Every order comes with:

- Results in 2 to 3 days, in the app
- Physician follow-up if you want one
- Free Labcorp draw, or $75 at home
- No other fees. HSA and FSA eligible.

It’s also part of the [Base Core Annual – Men](https://picardo.health/labs/panels/base-core-men), [Base Core Annual – Women](https://picardo.health/labs/panels/base-core-women), [Brain Health Screening](https://picardo.health/labs/panels/brain-health), [Pregnancy](https://picardo.health/labs/panels/pregnancy), [Postpartum](https://picardo.health/labs/panels/postpartum), [Fertility](https://picardo.health/labs/panels/fertility), [Thyroid & Autoimmunity](https://picardo.health/labs/panels/thyroid-autoimmunity) and [Celiac / GI](https://picardo.health/labs/panels/celiac-gi) panels, if you want a wider checkup.

Already have a result? [Ask Picardo about it](https://app.picardo.health/auth).

## Questions people ask

### Is AST or ALT more important?

ALT is the more specific sign of liver damage.[1] But in a 2025 Finnish study of more than 20,000 adults, a raised AST predicted serious liver disease over the next 10 years better than a raised ALT did.[6] Clinicians read them together.

### What does an AST/ALT ratio above 2 mean?

It often points to alcohol, though a hard workout or muscle injury in the past week or two can do it too.[1][3] About 90% of people with alcohol-related liver disease have an AST higher than their ALT, and more than 70% have a ratio above 2.[1] AST above ALT can also be a sign of cirrhosis, whatever the cause.[1][2]

### How long should I avoid exercise before an AST test?

At least a week, and ideally two, after heavy or unfamiliar weightlifting. In a study of healthy young men, AST was still raised in most of them 7 days after a single hour of lifting, and ALT was still raised in most at 10 to 12 days.[3]

### Does a normal AST rule out liver disease?

No. AST and ALT are often normal in people whose fatty liver has already caused advanced scarring.[5] That’s why guidelines use FIB-4, which combines AST and ALT with your age and platelet count.[5]

## Often checked alongside

- [ALT](https://picardo.health/guides/biomarkers/alt.md): The enzyme most specific to liver damage
- [GGT](https://picardo.health/guides/biomarkers/ggt.md): A liver enzyme that rises with alcohol
- [ALP](https://picardo.health/guides/biomarkers/alp.md): An enzyme from liver and bone
- [Platelet count](https://picardo.health/guides/biomarkers/platelets.md): Cells that help blood clot

## Test details

- **Labcorp test:** Metabolic Panel (14), Comprehensive, 322000
- **LOINC:** 1920-8
- **Sample:** Blood
- **Fasting:** Not needed for AST itself. The metabolic panel it comes on asks for 12 hours, for its glucose result.
- **Typical lab range:** 0 to 40 IU/L[9]
- **Units:** IU/L, the same as U/L

## Sources

1. Kwo PY, Cohen SM, Lim JK. ACG clinical guideline: evaluation of abnormal liver chemistries. Am J Gastroenterol. 2017;112(1):18–35. https://doi.org/10.1038/ajg.2016.517
2. Kwo PY, Masuoka HC, Schaefer EA, Friedman LS. Evaluation of abnormal liver biochemical test results. Gastroenterology. 2026;170(7):1457–1472. https://doi.org/10.1053/j.gastro.2025.12.041
3. Pettersson J, Hindorf U, Persson P, et al. Muscular exercise can cause highly pathological liver function tests in healthy men. Br J Clin Pharmacol. 2008;65(2):253–259. https://doi.org/10.1111/j.1365-2125.2007.03001.x
4. Crabb DW, Im GY, Szabo G, et al. Diagnosis and treatment of alcohol-associated liver diseases: 2019 practice guidance from the American Association for the Study of Liver Diseases. Hepatology. 2020;71(1):306–333. https://doi.org/10.1002/hep.30866
5. Rinella ME, Neuschwander-Tetri BA, Siddiqui MS, et al. AASLD Practice Guidance on the clinical assessment and management of nonalcoholic fatty liver disease. Hepatology. 2023;77(5):1797–1835. https://doi.org/10.1097/HEP.0000000000000323
6. Åberg F, Jula A, Salomaa V, et al. Updated reference limits for liver blood tests with validation against long-term liver-related outcomes. Liver Int. 2025;45(12):e70440. https://doi.org/10.1111/liv.70440
7. Schillie S, Wester C, Osborne M, et al. CDC recommendations for hepatitis C screening among adults—United States, 2020. MMWR Recomm Rep. 2020;69(2):1–17. https://doi.org/10.15585/mmwr.rr6902a1
8. Conners EE, Panagiotakopoulos L, Hofmeister MG, et al. Screening and testing for hepatitis B virus infection: CDC recommendations—United States, 2023. MMWR Recomm Rep. 2023;72(1):1–25. https://doi.org/10.15585/mmwr.rr7201a1
9. Labcorp. Comprehensive metabolic panel (14), test 322000: sample report. Labcorp test menu. Accessed October 28, 2026. https://files.labcorp.com/testmenu-d8/sample_reports/322000.pdf

Updated 2026-10-28. This is general health information, not medical advice: talk to your clinician about your results and before changing any treatment.