AST is one of the two liver enzymes. it stands for aspartate amino transferase. This enzyme is also known as SGOT, which stands for serum glutamic-oxaloacetic transaminase. AST is a protein that is synthesized in the liver cells. When there is liver complication or damage, this enzyme leaks out and enters the blood stream, something that leads to increased level of this type of protein in blood. AST is also found in other parts of the body apart from liver. The enzyme may be found in heart, red blood cells, muscle tissue, kidneys, and pancreases.
An AST test is used to measure the amount of this enzyme in blood. Usually, there are low levels of this enzyme that are found in blood. However, when organs like the liver and heart are damaged or suffer from a disease, more AST is released into the blood. The amount released to bloodstream may directly relate with the seriousness or extent of tissue damage.
When there is severe damage of the tissues, the level of AST rises after a period of 6 to 10 hours following the damage and this level may remain high for a period of close to four days. AST test could be conducted when performing alanine aminotransferase test, another liver enzyme, which is also known as ALT.
Sometimes, the levels of AST and ALT may be used to determine if a person suffers liver damage or damage of another organ. The latter is also incorporated when testing for the liver damage such as hepatitis C. In addition, many patients who suffer from hepatitis C show normal AST levels. Moreover, patients may have very serious liver disease such as cirrhosis and still show normal AST levels in blood.
Aspartate aminotransferase (AST) – Procedure, Normal Reading
Test for AST are done to check for liver damage. They are also helpful in identifying liver disease such as cirrhosis and hepatitis. A liver disease produces pain in the upper abdomen and may show other symptoms like vomiting, nausea, and jaundice. The test is also used to examine the success in treatment of liver disease. This test may be done to determine if a jaundice condition may have been caused by a liver disease or blood disorder.
Patients being treated of cholesterol levels may undergo AST test to help determine the effects of cholesterol medication such as damage to the liver. A blood sample is taken from a vein in a person’s arm. The patient is wrapped an elastic band around the upper arm and a needle is used to draw blood from the vein.
The normal values for AST in males are 14-20 units per liter or U/L, which may be translated to 0.23 to 0.33 microkats per liter or mckat/L. In females, the normal ranges are defined as 10- 36 U/L, which may be translated as 0.17 to 0.60 mckat/L. These values can vary from one laboratory to another and the doctor may consider other factors to determine the normal ranges for an individual. Values that fall outside these ranges may still be considered as normal depending on other factors.
Causes of high levels of AST
Elevated levels of AST may be triggered by damage of the liver due to conditions like cirrhosis and hepatitis. They may also be caused by decaying tumor or necrosis. Other conditions like heart attack, heart failure, kidney, and lung damage may also cause the AST levels to rise. Use of medications such as antibiotics, statins, narcotics, aspirin, chemotherapy, and harbutures may also cause the levels of AST to increase passed normal ranges.
When a person takes high doses of vitamin A, it may cause the liver enzyme to rise. Some types of cancer also increase the level of AST in blood. The AST test is more effective when detecting liver damage caused by over consumption of alcohol than alanine aminotransferase (ALT) test. At times, both tests may be used to establish if the damage of the liver was caused by alcohol dependence.
Since other many conditions can elevate the levels of AST in blood, patients may undergo other tests to interpret the normal results. A high AST reading may indicate that there is a liver damage however; the damage may not necessarily be caused by hepatitis C. If a test shows that there is high amount of AST but the ALT enzyme is normal, this may indicate that the cause for the increased levels of AST may be emanating from other parts of the body. The exact levels of AST may not clearly indicate the extent of liver damage or whether the liver is getting worse or better. Usually, small changes of the enzyme in blood are expected time in time, which may not be a course for concern.