What levels of serum transaminases suggest extrahepatic biliary obstruction?

Updated: Oct 16, 2019
  • Author: Jennifer Lynn Bonheur, MD; Chief Editor: Vinay Kumar Kapoor, MBBS, MS, FRCS, FAMS  more...
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Answer

Usually, serum aspartate aminotransferase (AST) levels are not elevated unless secondary acute parenchymal damage is present. When elevations occur, they are usually only mild to moderate (< 10 times the upper reference limit). However, when extrahepatic obstruction occurs acutely, AST values may quickly rise to more than 10 times the normal value, and then they fall after approximately 72 hours. With time and progressive hepatocyte damage caused by distended biliary ductules, an elevation in AST levels may be observed. A 3-fold or more increase in ALT strongly suggests pancreatitis.


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