Mildly Elevated Transaminases (ALT, AST) : Why And What To Do

Mildly elevated transaminase is seen in upto 1-9% of population. It signifies ongoing liver injury. There are varied common and uncommon hepatic and extrahepatic causes for this. Evidence regarding the corect approach of evaluation is limited and the expert consensus is for step based approach for this problem. Detailed history and examination is of paramount importance. With the ease of doing liver function test (LFT) due to availabilty of automated machines, more and more such tests are being asked for. In many such instances the result is mildly elevated liver enzymes. Mildly elevated liver enzymes in a seemingly normal individual trouble even an experienced physician.An estimated 1% to 9% of people who have no symptoms have high liver enzyme levels when screened with standard biochemistry panels.A US survey showed elevated alanine aminotransferase (ALT) in 8.9% of surveyed people from 1999 to 2002, an increase from previous reports. Significance of Transaminases Both aspartate aminotransferase (AST) and ALT are present in hepatocytes and are released into the blood in greater amounts when hepatocytes are damaged. ALT is predominantly present only in liver while AST is also seen in myocyte and erythrocytes.Because of this elevations in ALT are more specific for liver injury. Normally these are present in serum at low levels, usually less than 30 to 40 U/L. Although the actual values may differ from laboratory to laboratory, normal serum levels are usually less than 40 U/L for AST and less than 50 U/L for ALT. Dr Vibhu V Mittal Vol. 11, Issue 4, October 2012 Dr Vibhu V Mittal