AST (SGOT) Blood Test: How to Interpret Results

Medically reviewed by Rony Kampalath, MD

If you’ve recently had an AST test or will soon get one, you may be wondering what AST tests look for and how to interpret the results. "AST" stands for "aspartate aminotransferase," an enzyme usually found in the liver but that can also be found in the muscles and other organs of the body, such as the heart and pancreas.

An AST test measures the amount of AST in your blood, which can help healthcare providers determine your liver health and assist in diagnosing liver damage or liver disease, along with other health conditions.

You may get an AST test as part of routine blood work or as part of liver function tests if you have symptoms of liver damage. AST was formerly termed "SGOT," which stands for "serum glutamic-oxaloacetic transaminase." An AST test and an SGOT test are the same test.

This article discusses what constitutes low and high AST (SGOT) values, what causes high AST levels and when they’re concerning, and what to do about low or high AST levels.

AST Levels: What's Low, Average, and High?

Generally, the normal range of an AST test is 8 to 33 units per liter (U/L). Test values below 8 U/L might be considered low, while test values above 33 U/L might be considered high.

It’s important to note that the definition of “normal range” may differ slightly from one lab to another. It’s best to talk with a healthcare provider about which AST values are considered normal for you and which values would require further discussion on the health of your liver.

Reasons to Have an AST Lab Test

A healthcare provider may order an AST test as part of a routine checkup on the health of your liver or if you have symptoms of liver damage or are at increased risk of liver disease. You might also get an AST test as part of routine monitoring if you have liver disease.

Symptoms that might prompt a healthcare provider to recommend an AST test include:

• Loss of appetite

• Feeling overly tired and weak

• Nausea and vomiting

• Itching often

• Urine that’s dark in color or stool that’s light in color

• Skin or whites of the eyes turning yellow (jaundice)

• Abdominal pain or swelling

• Swollen legs or ankles

Note that many of these symptoms are associated with a wide range of medical conditions and, therefore, don’t automatically mean there are liver problems. Be sure to talk with a healthcare provider about these symptoms so that they can offer an accurate diagnosis and subsequent treatment.

A healthcare provider might also recommend an AST test if you have a higher risk of developing liver disease. Factors that might increase your risk include:

• Living with alcohol use disorder

• Having a family history of liver disease

• Taking medicines that can cause liver damage

• Living with hepatitis or having been exposed to hepatitis

• Having a weight that is considered obesity

• Living with diabetes

If you are living with one of the above risk factors, you might not necessarily show symptoms of liver damage, but a healthcare provider may still recommend an AST test to check for underlying liver damage or monitor your liver health, given the increased risk of developing liver disease.

When Are Blood Test Results Concerning?

High values on an AST test mean that there are high levels of AST in the blood. High levels of AST may be a sign of certain liver diseases or other health conditions, including:

• Cirrhosis (scarring of the liver)

• Hepatitis (liver inflammation, often due to hepatitis viruses)

• Mononucleosis (an infectious viral disease)

• Pancreatitis (inflammation of the pancreas)

• Heart problems

Indication of liver disease is more likely if you also have high values on other liver function tests, such as an ALT (alanine aminotransferase) test, ALP (alkaline phosphatase) test, or a bilirubin test.

If your AST test results are not within the normal range, it’s understandable to feel concerned. However, AST values outside the normal range don’t necessarily mean you have a liver problem or health condition needing treatment.

AST test results can be affected by factors outside your control, such as your age and sex, as well as your diet and certain medications. AST levels may also be increased due to certain health events, such as:

• Having a surgical procedure, including a heart procedure

• Sustaining a deep burn

• Having a seizure

• Being pregnant

• After exercising

Always talk with a healthcare provider to help you make sense of AST test results so that you can know if it’s something to be concerned about, something to be monitored, or something you need not worry about.

Low or High AST Levels: What Happens Next?

AST levels outside the normal range may prompt a discussion with a healthcare provider. Recommended next steps after receiving low or high AST test results will depend on the underlying cause. For example, higher-than-average AST levels may be a sign of liver damage. Further liver function tests may be needed to reach a diagnosis and determine treatment.

If you are at increased risk of liver damage and have AST levels outside the normal range, a healthcare provider may recommend prevention tips or treatment, depending on the current health of your liver, to lower your risk of liver disease.

Talk with a healthcare provider about next steps after an abnormal AST test result, including ways to promote liver health.

Modifiable vs. Unmodifiable Risk Factors of Liver Disease

Certain risk factors for liver disease are unmodifiable, meaning you can’t change them, such as having a family history of liver disease or living with diabetes.

Other risk factors are modifiable, meaning you can change them, such as getting help for alcohol use disorder or talking to your healthcare provider about switching to medications that don’t potentially cause liver damage, where possible.

Regardless of your AST test results, you can make changes to promote liver health. For example, research has shown that physical activity is associated with a lower risk of chronic liver disease. Other research has suggested that higher vegetable intake is associated with lower levels of ALT, though more research is needed to determine how diet may impact AST levels.

Ask a healthcare provider about tangible ways you can ensure your liver is as healthy as possible and reduce the risk of liver problems.

Summary

An AST test looks for blood levels of aspartate aminotransferase, an enzyme found mostly in the liver. Higher-than-average AST levels may be a sign of liver damage or liver disease, though there may be other causes at play.

When reviewing your AST test results, it’s important to keep in mind that while values outside the normal range may indicate liver problems, it’s not always the case. A healthcare provider can help you interpret what your AST test results mean for you and recommend the next steps to promote liver health and prevent liver disease.

Read the original article on Verywell Health.