Which enzyme is most specific for hepatocellular injury?

Which enzyme is most specific for hepatocellular injury?

• A. AST
• B. ALP
• C. GGT
• D. ALT (alanine aminotransferase)

Answer: (D)

ALT is the most specific marker for hepatocellular injury because it is highly concentrated in liver cells and is released into the blood when hepatocytes are damaged. AST is also found in the liver but is present in heart, muscle, and other tissues, so elevations can come from nonhepatic sources. ALP mainly rises with cholestasis or bone turnover, and GGT increases with biliary disease and other factors but is not as liver-cell–specific. Therefore, ALT provides the most liver-specific signal of hepatocellular damage.

ALT is the most specific marker for hepatocellular injury because it is highly concentrated in liver cells and is released into the blood when hepatocytes are damaged. AST is also found in the liver but is present in heart, muscle, and other tissues, so elevations can come from nonhepatic sources. ALP mainly rises with cholestasis or bone turnover, and GGT increases with biliary disease and other factors but is not as liver-cell–specific. Therefore, ALT provides the most liver-specific signal of hepatocellular damage.