Aspartate aminotransferase (AST) is an enzyme found in cells throughout the body but mostly in the heart and liver and, to a lesser extent, in the kidneys and muscles. In healthy individuals, levels of AST in the blood are low. When liver or muscle cells are injured, they release AST into the blood. This makes AST a useful test for detecting or monitoring liver damage.
The liver is a vital organ located in the upper right-hand side of the abdominal area just beneath the rib cage. It is involved in many important functions in the body. The liver helps to process the body's nutrients, manufactures bile to help digest fats, produces many important proteins such as blood clotting factors, and breaks down potentially toxic substances into harmless ones that the body can use or excrete.
A number of conditions can cause injury to liver cells and may cause increases in AST. The test is most useful in detecting liver damage due to hepatitis, drugs toxic to the liver, cirrhosis, or alcoholism. AST, however, is not specific for the liver and may be increased in conditions affecting other parts of the body.
An AST test is often performed along with an alanine aminotransferase (ALT) test. Both are enzymes found in the liver that become elevated in the blood when the liver is damaged. A calculated AST/ALT ratio is useful for differentiating between different causes of liver injury and in recognizing when the increased levels may be coming from another source, such as heart or muscle injury.
SGOT test is done detect liver damage and/or to help diagnose liver disease. When a healthcare practitioner thinks that you have symptoms of a liver disorder, such as abdominal pain, nausea and vomiting, jaundice (yellow skin), or potential exposure to a hepatitis virus; as part of a comprehensive metabolic panel SGOT test is done.
AST or SGOT test may be ordered as part of a comprehensive metabolic panel (CMP) when someone has a routine health examination.
An AST test or SGOT may be ordered along with several other tests when a person has signs and symptoms of a liver disorder. Some of these may include:
Loss of appetite.
Abdominal swelling and/or pain.
Dark urine, light-colored stool.
Swelling in the legs and ankles.
Tendency to bruise easily.
AST or SGOT test may also be ordered, either by itself or with other tests, for people who are at an increased risk for liver disease since many people with mild liver damage will have no signs or symptoms. Some examples include:
Persons who might have been exposed to hepatitis viruses.
Persons who are heavy drinkers.
Persons who have a history of liver disease in their family.
Persons taking drugs that can damage the liver.
Persons who are overweight and/or have diabetes.
When AST or SGOT test is used to monitor treatment of persons with liver disease, it may be ordered on a regular basis during the course of treatment to determine whether the therapy is effective.