Which liver function test combination is used in horses?

• A. Alanine transaminase and aspartate aminotransferase
• B. Electrolytes and blood urea nitrogen
• C. Gamma-glutamyl transferase and sorbitol dehydrogenase
• D. Amylase and lipase

Answer: (C)

In horses, evaluating liver disease relies on enzymes that reflect different parts of liver injury. Sorbitol dehydrogenase is highly specific to the liver in equines and rises quickly when hepatocytes are damaged, making it a good indicator of hepatocellular injury. Gamma-glutamyl transferase signals biliary tract problems and cholestasis, so it helps detect cholestatic or biliary disease. Using these two together covers both major pathways of liver injury, giving a clearer picture of liver function in horses.

Other options don’t target the horse liver as effectively. Electrolytes and blood urea nitrogen mainly reflect kidney function and hydration status, not liver health. Amylase and lipase pertain to pancreatic function, not the liver. ALT and AST can be less reliable in horses because ALT is not as liver-specific and AST can come from muscle, muddying the hepatic signal.