SGOT, now more commonly called AST, is a liver enzyme measured in routine blood tests to check for damage to the liver and other organs. The letters stand for serum glutamic-oxaloacetic transaminase (SGOT) and aspartate aminotransferase (AST). They refer to the same enzyme. If you’ve seen either abbreviation on your lab results, here’s what it means and why it matters.
What AST Actually Does in Your Body
AST is an enzyme that helps transfer chemical groups between amino acids, the building blocks of protein. Specifically, it shuttles a nitrogen-containing group between two amino acids called aspartate and glutamate. This reaction is part of how your body processes protein and generates energy.
The enzyme lives inside your cells, not floating freely in your blood. It’s found mainly in the liver, but also in the heart, skeletal muscles, kidneys, brain, and red blood cells. Under normal conditions, only small amounts leak into the bloodstream as cells naturally turn over. When tissue is damaged, though, cells break open and release much more AST. That spike is what your blood test picks up.
Normal AST Ranges
AST is measured in units per liter (U/L). Normal ranges vary slightly between labs, but the general benchmarks are:
- Adult males (14+): 8 to 48 U/L
- Adult females (14+): 8 to 43 U/L
- Boys (1 to 13): 8 to 60 U/L
- Girls (1 to 13): 8 to 50 U/L
Some labs report a tighter range, such as 8 to 33 U/L for adults. This is why your result might be flagged as “high” at one lab but fall within range at another. Always compare your number to the reference range printed on your specific report rather than a number you found online.
Children naturally run higher than adults because their bodies are growing rapidly, which means more cell turnover. Values also tend to be slightly higher in males than females at every age.
What High AST Levels Mean
An elevated AST signals that cells somewhere in your body have been injured or destroyed, releasing the enzyme into your bloodstream. Because AST exists in several organs, a high number alone doesn’t pinpoint the cause. Context matters: how high the number is, which other markers are also elevated, and what symptoms you have.
The most common reasons for a high AST are liver-related:
- Viral hepatitis (hepatitis A, B, or C), which can push AST levels into the hundreds or even thousands
- Alcoholic hepatitis and heavy alcohol use over time
- Autoimmune hepatitis, where the immune system attacks liver cells
- Fatty liver disease, often linked to obesity or metabolic syndrome
- Cirrhosis, the late-stage scarring of liver tissue
- Medications that stress the liver, including some over-the-counter pain relievers and cholesterol drugs
But because AST also lives in muscle and heart tissue, non-liver causes are worth knowing about. Intense exercise, especially heavy weightlifting or long-distance running, can temporarily raise AST. So can a heart attack, which damages heart muscle cells. Conditions that break down skeletal muscle, sometimes triggered by severe injury or certain medications, will elevate AST as well.
Why Doctors Look at AST Alongside ALT
Your lab results probably show another enzyme right next to AST: ALT (alanine aminotransferase). ALT is found almost exclusively in the liver, while AST is spread across multiple organs. Comparing the two helps narrow down where the damage is coming from.
When both AST and ALT are elevated, the liver is the most likely source. The ratio between them offers additional clues. In most types of liver disease, ALT rises higher than AST. But in alcohol-related liver damage, the pattern often flips: AST tends to be higher than ALT, sometimes by a factor of two or more. This ratio isn’t diagnostic on its own, but it gives your doctor a direction to investigate.
If AST is high while ALT is normal, the problem is more likely in the heart or muscles rather than the liver. That’s when your doctor may order additional tests targeting those organs.
What Happens After an Abnormal Result
A single elevated AST reading doesn’t necessarily mean something serious is wrong. Temporary spikes happen after a hard workout, a night of heavy drinking, or even from a supplement that irritates the liver. In many cases, your doctor will simply repeat the test in a few weeks to see if the number comes back down on its own.
If the elevation persists, expect follow-up testing. This typically includes a broader liver panel with additional enzymes that help distinguish between different types of liver problems. Your doctor may also order tests for hepatitis viruses, check your iron levels, or request imaging like an ultrasound to look at the liver’s structure. The goal is to figure out which organ is involved and what’s causing the damage.
Mildly elevated results (just above the upper limit) are extremely common and often tied to medications, alcohol use, or weight. Levels in the hundreds suggest active inflammation. Levels in the thousands point to acute injury, such as a new hepatitis infection, a toxin exposure, or severely reduced blood flow to the liver.
Factors That Can Skew Your Results
Several everyday factors can push your AST number higher without indicating real disease. Vigorous exercise within a day or two before the test is one of the most common culprits. Even moderate strength training can temporarily double your AST. If you’re an active person with a mildly elevated result, it’s worth mentioning your exercise routine to your doctor and retesting after a few rest days.
Certain supplements, particularly herbal products marketed for weight loss or bodybuilding, can irritate the liver enough to raise enzyme levels. Alcohol consumed in the days before the test will also affect results. Some prescription medications are well-known to cause mild, ongoing elevations that are monitored but not necessarily dangerous.
No special fasting is required for an AST test on its own, though your doctor may ask you to fast if they’re running a broader metabolic panel at the same time.