Aspartate aminotransferase (AST) is an enzyme primarily found in the liver and heart. To a lesser degree, it is also present in other parts of the body, including the kidneys and muscles. This enzyme is also called serum glutamic-oxaloacetic transaminase (SGOT).
Most people have low levels of this enzyme. However, when liver cells are damaged or hurt, they excrete extra AST into the blood.
- The enzyme known as SGOT contributes to the functioning of the liver's cells. It also helps the heart and kidneys, to a lesser extent.
- SGOT also helps the heart and kidneys, to a lesser extent.
- Low levels of SGOT in the blood are relatively common and not a cause for concern.
Healthy SGOT ranges
When the test results are in, a person's SGOT ranges may be classified as normal, high, or low. These ranges vary, depending on a person's sex. Normal ranges also differ among laboratories.
However, doctors tend to accept the following ranges as normal:
- Males: 10 to 40 units per liter (U/L)
- Females: 9 to 32 U/L
What do the results mean?
A doctor will explain the results of the SGOT test, including ALT levels if those are taken as well.
The doctor may test for levels of another liver enzyme at the same time. This enzyme is called alanine aminotransferase (ALT). If both ALT and SGOT levels are high, it may indicate that a person has one of the following conditions:
- extensive liver damage from toxins like alcohol or over-the-counter painkillers
- acute hepatitis
- gallbladder disease
- in pregnant women, preeclampsia or HELLP syndrome, which is defined by its characteristics — hemolysis, elevated liver enzymes, and low platelet count.
High SGOT levels without high ALT levels can indicate the following problems:
If the results of the test show high levels of SGOT, the liver or another organ that produces the enzyme may be damaged due to illness or injury.
Why is the SGOT test performed?
Doctors primarily use the SGOT test to check for and assess liver problems. The SGOT protein is mainly manufactured in the liver. When the liver is damaged or ill, SGOT can leak from the liver into the bloodstream. When this happens, levels in the blood will be higher than normal.
If a person has heart or kidney problems, levels of SGOT may be particularly high. To rule these issues out, doctors often order a check of the second liver enzyme, ALT, at the same time. If both levels are high, it indicates a problem with a person's liver. If only SGOT levels are high, this may indicate a problem with another organ or system.
Doctors commonly order the test if they suspect that a person has any of the following conditions:
How is the SGOT test done?
The SGOT test involves a blood sample being taken for analysis.
The SGOT test is very straightforward, and a person can expect it to be like any other blood test. A technician will seat the person in a chair and tie an elastic band around their arm.
The technician will then examine the arm for a suitable vein. After finding the vein, they will clean the site with an alcohol swab.
The technician will then insert a small needle into the vein and draw blood. The draw will not take long, only a couple of minutes.
When a vial has filled with blood, the technician will remove the needle and instruct the person to hold a gauze against the site of the insertion. The technician will remove the elastic band and secure the gauze with medical tape.
Because the SGOT test is straightforward, no special preparation is necessary. However, a person can take steps to ensure that the test goes smoothly.
Avoid over-the-counter medications, including pain relievers such as ibuprofen or acetaminophen, for 2 days before the SGOT test. If the test is performed without notice, a person should let their doctor know that they have recently taken over-the-counter medication.
Stay hydrated before any blood test. Drinking plenty of water on the day of the test can make blood easier to draw.
Wear a loose-fitting or short-sleeve shirt, to allow easier access to the veins in the elbow.
As with any blood test, very few risks are associated with the SGOT test. They include:
- bleeding at the site of the blood draw
- minor bruising
- feeling faint
A person is less likely to feel faint if they are well hydrated. Bleeding and bruising at the site are normally very minor and tend to resolve on their own.
A doctor will often order tests that coincide with the SGOT test or follow it. This is to help ensure proper diagnosis and determine the best course of treatment. These tests may include:
- Platelet count: Low platelet levels may indicate liver disease or, during pregnancy, HELLP syndrome.
- Coagulation panel: This measures the functioning of clotting-related proteins that the liver produces.
- Complete metabolic panel: This assesses how well the kidneys and liver are working and shows levels of electrolytes.
- Bilirubin test: This checks levels of a byproduct created when the liver breaks down red blood cells.
- Glucose test: When the liver is not working well, glucose levels may be low.
A doctor can take a closer look at a person's liver with an ultrasound scan. The extent of follow-up testing will depend on a person's results.