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Alanine aminotransferase (ALAT, ALT, GPT)

Clinical significance

1) Physiologic changes in the catalytic concentration of ALT in serum
The catalytic activity of ALT is decreased in normal umbilical blood; the concentration gradually rises to reach maximal values on day 5 postnatally.

2) Pathologic changes in the catalytic concentration of ALT in serum
A) Increased values of the catalytic concentration of ALT in serum are found in:
• active cirrhosis,
• acute extrahepatic biliary obstruction (ALT usually greatly exceeds AST),
• acute hepatitis;
considerable increase, which is relatively greater than AST increase; ALT level is also increased in jaundice-free episodes.
• dermatomyositis,
• hepatotoxic lesions,
• infectious mononucleosis (highest ALT level in the second week, returning to normal ALT value in the fifth week of disease),
• infectious or toxic hepatitis,
• initial therapy with clofibrate,
• myocardial infarction (smaller increase in comparison to AST),
• obstructive jaundice,
• primary or metastatic liver carcinoma,
• progressive muscular dystrophy,
• relapse of liver cirrhosis,
• therapy with salicylates (plasma concentration >250 mg/L),
• viral hepatitis.
B) Decreased values of the catalytic concentration of ALT in serum are found in:
• vitamin B6 deficiency