Which enzyme is described as a nonspecific indicator of liver injury?

Which enzyme is described as a nonspecific indicator of liver injury?

• A. ALT
• B. AST
• C. ALP
• D. LDH

Answer: (D)

Lactate dehydrogenase is found throughout many tissues—liver, heart, muscle, kidneys, brain, and red blood cells—so when cells are damaged, LDH leaks into the bloodstream. This makes LDH a nonspecific marker of tissue injury; it can rise with liver injury but isn’t unique to the liver. In contrast, alanine aminotransferase is highly concentrated in hepatocytes and more liver-specific, while aspartate aminotransferase is present in other tissues as well, though still associated with hepatocellular injury. Alkaline phosphatase relates more to biliary processes and bone, not as a direct indicator of hepatocellular injury. Therefore, LDH best fits the description of a nonspecific indicator of liver injury.

Lactate dehydrogenase is found throughout many tissues—liver, heart, muscle, kidneys, brain, and red blood cells—so when cells are damaged, LDH leaks into the bloodstream. This makes LDH a nonspecific marker of tissue injury; it can rise with liver injury but isn’t unique to the liver. In contrast, alanine aminotransferase is highly concentrated in hepatocytes and more liver-specific, while aspartate aminotransferase is present in other tissues as well, though still associated with hepatocellular injury. Alkaline phosphatase relates more to biliary processes and bone, not as a direct indicator of hepatocellular injury. Therefore, LDH best fits the description of a nonspecific indicator of liver injury.