What Is Aspartate Aminotransferase Test For?

What is aspartate aminotransferase?

The aspartate aminotransferase test (AST) test is a blood test that checks for liver damage.  

Your liver is an organ that has many important jobs. It makes a fluid called bile which helps in digesting the food. It also eliminates waste products and other toxins from your blood. It produces proteins, as well as substances which helps to clot your blood. Alcohol or drug use and diseases such as hepatitis can damage your liver and keep it from doing their jobs.

AST is a liver enzyme. Other organs, like heart, kidneys, brain, and muscles, also make smaller amounts. AST is also called SGOT

Generally, aspartate aminotransferase test levels are low in your blood. When your liver is damaged, it puts more AST into your blood, and your AST levels rise.

A high AST level is a sign of liver damage, but it can also mean that you have damage to another organ that makes it, like your heart or kidneys. That's why doctors often do the AST test together with tests of other liver enzymes.

Why would I need this test?

 symptoms of liver damage, such as:

• Jaundice
• Tiredness
• Weakness
• Swollen belly
• Stomach pain
• Appetite loss
• Itchy skin
• Dark-colored urine
• Light-colored poop
• Swelling in your legs and ankles
• Bruises

Other reasons to have this test:

• exposed to the hepatitis virus.
• a lot of alcohol.
• medicine that's known to damage the liver.
• family history of liver disease.
• obesity.
• diabetes or metabolic syndrome.
• nonalcoholic fatty liver disease.

Your doctor might also want you to get this test to see if treatments you take for liver disease are working.

The AST test is also part of a comprehensive metabolic panel -- a blood test your doctor does as part of a routine exam.

Risk factors –

• Bleeding
• Bruising
• Infection
• Pain when the needle is inserted
• Fainting or feeling dizzy

What do the results mean?

You should have the results within a day. They are given in units per liter (units/L). Normal ranges are:

• Males: 10 to 40 units/L
• Females: 9 to 32 units/L

Higher-than-normal AST levels can be caused by:

• Chronic hepatitis
• Cirrhosis 
• Blockage in the bile ducts  
• Liver cancer

Very high AST levels can be caused by:

• Acute viral hepatitis
• Damage to the liver from drugs or other toxic substances
• A blockage in blood flow to the liver

Your doctor might also compare your aspartate aminotransferase test and ALT levels. If you have liver disease, usually your ALT level will be higher than your AST level.

These other conditions not tied to your liver can also raise your AST level:

• Burns
• Heart attack
• Intense exercise
• Muscle injury
• Pregnancy
• Pancreatitis
• Seizures
• Surgery

Some diseases or medicines you take can cause a “false positive” result on the aspartate aminotransferase test. This means your test is positive, even though you don't have liver damage. Any of these can cause a false positive result:

• Diabetic ketoacidosis
• Some antibiotics, such as erythromycin estolate or para-aminosalicylic acid