Aspartate transaminase (aspartate aminotransferase, AST or GOT) has two isoenzymes in the liver, which are present in hepatocyte mitochondria (mAST) and intracytoplasmic (sAST) ( this is different from ALT). In the case of mild hepatic lesions, only sAST is released into the blood. If the lesion is severe, mAST is also released into the blood. Therefore, serum AST activity increases with the degree of hepatocyte damage. When liver cells are damaged, ALT will firstly be released into the blood. When liver cells are severely damaged and this will endanger the mitochondria. Thus AST also enters the blood. When someone is infected with hepatitis and liver disease, AST will increase with ALT. If it is high but short-lived, it may be sAST. The clinical significance is the same as ALT. If AST level increases slightly than ALT level and the amplitude is not too large but the duration time is long, it may be mAST. This suggests chronic and progressive lesions.
If the value of hepatitis patients stay high, it reflects that liver cell inflammation has not stopped, and hepatocyte swelling and necrosis persist. Patients with long liver disease, high degree of chronic disease, severe hepatocyte parenchymal damage, early cirrhosis usually have a high AST value, and the ratio of ALT/AST is less than 1.
Aspartate transaminase has the highest vitality in the heart, followed by the liver. Although there are more sensitive and specific indicators for heart disease, there is also AST in the detection of myocardial enzymes.
It is worth noting that:
1. Acute soft tissue injury, strenuous exercise, pregnancy, eating, drinking, staying up late, drugs, overwork and eating greasy food can cause transient AST elevation. You can be reviewed if necessary.
2. AST activity reduction is generally meaningless.
3. The ALT and AST ratios have the significance for judging the course and prognosis of liver disease when both are elevated.
4. AST increased to more than 10 times the normal level, suggesting hepatic hypoxia and calculi obstruction of the bile duct.