AST blood test: normal range and what a high AST means

An AST blood test measures aspartate aminotransferase, an enzyme found in the liver and also in heart, skeletal muscle and kidney. A raised AST means cells that hold it have released more than usual, and the useful question is which cells. That is why AST is usually read next to ALT, which comes mainly from the liver. Older reports may call it SGOT.

What AST measures

AST is an enzyme, a protein that speeds up chemical reactions inside cells. It sits in two places inside each cell, the cytoplasm and the mitochondria. Mild injury mainly releases the cytoplasmic form, and more severe damage releases more of the mitochondrial form. Blood normally carries a low level, and MedlinePlus notes that low AST is usually considered normal.

Because so many tissues hold AST, it is less specific to the liver than ALT. It still has its own value: the British Society of Gastroenterology notes that AST can be the more sensitive signal of liver injury in alcohol-related liver disease and in some cases of autoimmune hepatitis.

AST normal range

AST is reported in units per litre (U/L, also written IU/L). Ranges vary by laboratory, method, age and sex:

Reference	Male	Female
Mayo Clinic Laboratories, age 14 and over	8 to 48 U/L	8 to 43 U/L
Mayo Clinic Laboratories, age 1 to 13	8 to 60 U/L	8 to 50 U/L
IFCC multicentre reference study, adults	11 to 34 U/L	11 to 34 U/L

The IFCC study, which used methods traced to a common standard, found the upper limits for men and women 1.7 U/L apart, close enough for one range. Read your result against the range printed on your own report.

What a high AST usually points to

When ALT is raised too

AST and ALT rising together, with ALP much less affected, points to stress on liver cells. The common reasons are the same as for ALT: fat in the liver (MASLD), alcohol, medicines and supplements, and viral hepatitis. Very large rises, ten or more times the upper limit, are typical of acute liver cell injury such as viral hepatitis.

The balance between the two enzymes carries information of its own. British guidance treats an AST:ALT ratio above 1 as one of the signals that liver scarring may be advanced, even when both values sit inside the range.

When AST is raised and ALT is not

An AST that rises alone can point away from the liver. Muscle is the usual suspect: hard exercise, a muscle injury or inflammation of muscle can all release it, and so can damage to heart muscle. MedlinePlus also lists pancreatitis, glandular fever (mononucleosis), seizures, deep burns and recent surgery among the reasons AST can rise.

A third possibility is the sample itself. When red cells burst in the tube after the blood is drawn (haemolysis), AST reads falsely high, and laboratory studies show the effect at levels of haemolysis too slight to see by eye. Mayo Clinic Laboratories rejects grossly haemolysed samples, and a fresh sample settles the question.

What a doctor typically looks at next

A doctor usually asks about exercise, muscle injury, alcohol and medicines, then reads AST with ALT, GGT, ALP and bilirubin. If muscle is suspected, creatine kinase (CK), a muscle enzyme, helps show whether muscle is the source; in the weightlifting study below, CK rose far more than AST. If fatty liver is likely, AST feeds into FIB-4, a fibrosis score:

FIB-4 = (age × AST) ÷ (platelet count × √ALT)

In British guidance, below 1.3 (or below 2.0 over the age of 65) means low risk of advanced scarring; 1.3 to 3.25 is indeterminate and usually leads to a second test, such as a scan of liver stiffness; above 3.25 is a reason to consider specialist referral. It is a sorting tool, not a diagnosis.

What moves AST

• Exercise. One hour of unaccustomed weightlifting raised AST and ALT significantly in 15 healthy men, and both stayed up for at least seven days.
• Alcohol. MedlinePlus lists drugs that are toxic to the liver, especially alcohol, among the causes of a high AST.
• Medicines, pregnancy, age and sex, which MedlinePlus lists among the things that affect results.
• Metabolic health. Across 17 studies, people with metabolic syndrome had AST about 2.7 U/L higher on average, a smaller gap than for ALT.
• Ramadan fasting. A 2021 review found a small fall in AST across Ramadan in healthy adults, pooled from 16 studies.

Preparing for the test

AST is usually ordered with other blood tests, and MedlinePlus notes you may need to fast for up to 12 hours before them. Avoid hard or unfamiliar training in the days before if you can, or mention it when the result is read; our guide to what to expect from a comprehensive blood test covers the rest of the preparation. Tell the person taking the sample about medicines, supplements and any recent muscle injury or illness. MedlinePlus advises against stopping any medicine unless your doctor tells you to.

How Clare's panel handles AST

Clare's panel includes AST, measured by the lab on the same draw as ALT and the rest of the liver markers. Clare then calculates the AST / ALT Ratio by dividing AST by ALT, so the two are always read together. The panel also includes Platelet Count, so every blood result that a FIB-4 score uses comes from the same draw.

AST and fatty liver risk in the UAE

UAE studies mostly use AST through FIB-4. Among 373 people with type 2 diabetes seen at a diabetes centre in Dubai in late 2023, 56 per cent had suspected MASLD and 2.7 per cent scored at high risk of advanced scarring. In a much larger group of adults attending Dubai Academic Health Corporation between 2018 and 2023, 21.7 per cent of those with a MASLD risk factor scored at moderate or high risk on FIB-4, as did 15 per cent of those without one. Both studies drew on people already using health services, and FIB-4 flags who needs a closer look rather than who has disease.

Price

AST is usually sold within a liver function test. When we read public prices on 11 October 2026, a liver function test cost from 89 to 1,100 at six UAE providers. The top figure was a wider package that adds a hepatitis B test; the five standard liver panels ran from 89 to 199. Most listings did not say whether VAT was included, and home collection can add a fee: one lab charged for it on smaller orders.

Related tests

AST is one part of the Liver function test. Read it with Alanine Aminotransferase (ALT), the more liver-specific partner; the AST / ALT Ratio, which Clare calculates from the two; and Platelet Count, the other blood result in FIB-4.

Why AST means more over time

AST moves quickly with exercise and with the handling of the sample, so a single raised value deserves a second look before it is read as a liver signal. A repeat after a stretch without hard training shows whether the rise came from muscle or from something steadier. Over longer spans, what matters is how AST moves with ALT: a ratio that climbs, or a FIB-4 that crosses a threshold, says more than either number on one day. When Clare opens, each member's results will sit in one health account, with each marker's trend over time.

Clare is opening with a waitlist at clare.health.