The AST test measures aspartate aminotransferase, an enzyme found in liver, skeletal muscle, heart and red cells. Practitioners read it with ALT and GGT to separate liver injury from training, alcohol or haemolysis, and the AST to ALT ratio adds information neither enzyme gives alone. Hard exercise in the prior week, a haemolysed sample and muscle injury can all raise it.
| Test type | Measured in a blood sample |
|---|---|
| Measurements required | AST only |
| Sample and collection | Blood draw at a collection centre |
| Preparation | This test doesn't need fasting on its own. |
| Turnaround | 3 to 5 business days |
| Available through | Liver Function Tests, part of the Baseline Health Check. Also in: Full Body Health Check, Weight Management Test. |
| Pricing | Included in the $99 Baseline Health Check |
| Results | Returned in the Vively practitioner platform, beside your client's other markers |
What are the AST reference and optimal ranges?
| Typical lab reference | Vively optimal | |
|---|---|---|
| Men | 5 to 40 U/L | 10 to 30 U/L |
| Women | 5 to 40 U/L | 10 to 20 U/L |
Labs differ, and some use a lower upper limit for women, so read the client's result against their report (RCPA guidance). The optimal range is a long-term target, not a diagnostic cut-off.
Check a client's AST result
Enter the value from your client's lab report to see where it sits against the typical lab range and the Vively optimal range.
A guide only, not a diagnosis. One result is a starting point: read it with symptoms, history and a repeat test. Labs differ, so check the result against the range on your client's report. Nothing you enter is stored or sent.
How do you arrange AST testing through Vively?
- Get verified. Practitioners with a recognised qualification or membership (ATMS, NHAA, ANTA, Dietitians Australia, NSA, CMA or Ahpra registration) can request free practitioner access.
- Choose a panel. Log in to the practitioner platform and pick a panel that includes AST, or build your own. It is included in the $99 Baseline Health Check.
- Client collects. Your client collects at a partner collection centre, with their request on their phone or printed.
- Review results. Results come back to you in the practitioner platform, beside your client's other markers, ready for the follow-up consult.
Which Vively panels include AST?
Log in to the practitioner platform to view a panel in full, or build and save your own from 100+ tests and panels.
- Baseline Health Check74 markers across 11 lab groups$99
One fasting blood draw.
Full Blood CountUrea, Electrolytes & CreatinineLiver Function TestsCalcium, Phosphate & MagnesiumLipid StudiesDiabetes & Glycaemic StudiesIron StudiesThyroid Function Tests+3 moreLog in to view this panel - Weight Management Test27 markers · Heart & metabolicPrice on sign-upASTTotal CholesterolLDL CholesterolHDL CholesterolNon-HDL CholesterolTriglyceridesFree testosteroneSHBG+19 moreLog in to view this panel
- Log in to view this panelFull Body Health Check87 markers · Health checksPrice on sign-up
Why does the optimal range sit there?
Our optimal ceilings sit below the 40 U/L lab limit, because reference ranges include people with undiagnosed fatty liver and recent hard exercise.
We apply the logic Prati and colleagues (2002) used for ALT: healthy, low-risk adults sit lower. The ceiling is lower for women because they have less muscle mass and lower rates of fatty liver.
AST is less liver-specific than ALT. A value between the optimal ceiling and the lab limit means little on its own.
AST also feeds into the FIB-4 score (with ALT, platelets and age), which GPs use to triage fibrosis risk in fatty liver.
What should AST be read with?
- ContextAST above ALT after hard training, normal GGT
Muscle source likely; repeat after three to seven quiet days.
- ContextAST more than twice ALT with high GGT or MCV
Classic alcohol pattern.
- ContextALT above AST, both raised, with high triglycerides
Fatty liver (MASLD), usually with insulin resistance.
- ContextAST rising to exceed ALT in known fatty liver
Can signal progressing fibrosis; the GP can calculate FIB-4.
- HighRaised AST with high bilirubin and low haemoglobin
Red cell breakdown (haemolysis) in the body, or a haemolysed sample.
What can affect a AST result?
- Hard or unfamiliar exercise: after a first heavy weights session, AST and ALT can stay raised for a week (Pettersson, 2008).
- A haemolysed sample releases red cell AST and falsely raises the result.
- Intramuscular injections, muscle injury and statin-related muscle effects.
- Alcohol, fatty liver and medicines or supplements that affect the liver.
- Hypothyroidism and untreated coeliac disease.
When should you refer the client to their GP?
- AST above about 150 U/L needs prompt review; above 500 U/L needs same-day medical attention.
- AST above range on a repeat test after a quiet week, especially with ALT or GGT also raised.
- AST more than twice ALT with a history of heavy drinking.
- Chest pain, jaundice, or muscle pain with dark urine: urgent review.
How should a client prepare for a AST test?
Copy or print this to send to your client.
Preparing for your AST test
- This test doesn't need fasting on its own.
- If your practitioner has requested the Baseline Health Check, fast for 8 to 12 hours before a morning collection (water is fine).
- Avoid heavy or unfamiliar exercise for three days before your test, as hard training can raise AST.
- Take your pathology request to any of 4,000+ collection centres. Bring it printed or on your phone.
- Keep taking prescribed medicines as usual unless your doctor tells you otherwise.
- Results usually take 3 to 5 business days and come to your practitioner. Book your results appointment for after that.
How do practitioners use AST with clients?
Ask about training in the week before the draw before reading an AST result. When the liver is the source, the levers match ALT: less alcohol, fructose and added sugar, more fibre, and weight loss where needed, with a retest after two to three months.
AST FAQs
Can a naturopath, nutritionist or dietitian order AST through Vively?
Yes. Add it to a client panel on the Vively practitioner platform. It is part of Liver Function Tests in the $99 Baseline Health Check, and is also in Full Body Health Check and Weight Management Test. No account yet? Request free access.
How long should a client avoid training before an AST test?
Ask for three days without heavy or unfamiliar training, and a week if they have just started lifting weights. Muscle releases AST after hard sessions, and in one study of untrained men AST and ALT stayed above range for at least seven days after a single session. Habitual training at a steady load matters less.
What does the AST to ALT ratio tell me?
It suggests the source. A ratio below 1 with both enzymes raised is typical of fatty liver. A ratio above 2 points towards alcohol. A rising ratio in someone with known fatty liver can signal fibrosis. The ratio means little when both enzymes sit in range or recent exercise has not been excluded.
What non-liver causes can raise AST?
AST also comes from muscle and red cells, so hard exercise, muscle injury, intramuscular injections and statin-related muscle effects can raise it. A haemolysed sample falsely raises it too. Raised AST with high bilirubin and low haemoglobin suggests red cell breakdown in the body. Hypothyroidism and untreated coeliac disease are further causes worth considering.
At what AST level should I involve the client's GP?
AST above about 150 U/L needs prompt review, and above 500 U/L needs same-day medical attention. Involve the GP as well if AST stays above range on a repeat after a quiet week, especially with ALT or GGT raised, or if AST is more than twice ALT with a history of heavy drinking. Chest pain, jaundice or muscle pain with dark urine needs urgent review.
References
- RCPA Manual. Aspartate aminotransferase.
- Pathology Tests Explained. Aspartate aminotransferase (AST). Source
- Pettersson J, Hindorf U, Persson P, et al. Muscular exercise can cause highly pathological liver function tests in healthy men. British Journal of Clinical Pharmacology. 2008. Source
- Kwo PY, Cohen SM, Lim JK. ACG Clinical Guideline: evaluation of abnormal liver chemistries. American Journal of Gastroenterology. 2017.