The examination of aspartate aminotransferase or oxalacetic transaminase (AST or TGO), is a blood test requested to investigate lesions that compromise the normal functioning of the liver, such as hepatitis or cirrhosis, for example.
Oxalacetic transaminase or aspartate aminotransferase is an enzyme present in the liver and is usually elevated when liver damage is more chronic, as it is located more internally in the liver cell. However, this enzyme can also be present in the heart and can be used as a cardiac marker, which may indicate infarction or ischemia.
As a liver marker, AST is usually measured together with ALT, as it may be elevated in other situations, being unspecific for this purpose. The reference value of the enzyme is between 5 and 40 U / L of blood, which may vary according to the laboratory.
What does high AST mean
Although the AST / TGO test is not very specific, the doctor can order this test together with others that indicate liver health, such as the gamma-glutamyltransferase (GGT), alkaline phosphatase (ALK) and, mainly ALT / TGP. Learn more about the ALT exam.
Increased AST, or high TGO, may indicate:
- Acute pancreatitis; Acute viral hepatitis; Alcoholic hepatitis; Liver cirrhosis; Liver abscess; Primary liver cancer; Major trauma; Use of drugs that cause liver damage; Heart failure; Ischemia; Infarction; Burns; Hypoxia; Bile duct obstruction, such as cholangitis, choledocholithiasis; muscle damage and hypothyroidism; use of drugs such as heparin therapy, salicylates, opiates, tetracycline, thoracic or isoniazid
Values above 150 U / L generally indicate some damage to the liver and above 1000 U / L can indicate hepatitis caused by the use of medications, such as paracetamol, or ischemic hepatitis, for example. On the other hand, decreased AST values may indicate vitamin B6 deficiency in the case of people who need dialysis.
Ritis reason
Ritis' reason is used in medical practice to assess the extent of liver damage and thus establish the best treatment for the situation. This ratio takes into account the AST and ALT values and when higher than 1 it is indicative of more serious injuries, such as cirrhosis or liver cancer, for example. When less than 1 it can be indicative of acute phase of a viral hepatitis, for example.
When the exam is ordered
The TGO / AST blood test can be ordered by the doctor when it is necessary to assess the health of the liver, after observing that the person is overweight, has fat in the liver or shows signs or symptoms such as yellowish skin color, pain on the right side abdomen or in the case of light stools and dark urine.
Other situations where it may also be useful to evaluate this enzyme are after using drugs that can damage the liver and to evaluate the liver of people who consume many alcoholic beverages.
