Which laboratory results would suggest a patient is experiencing liver injury?

Increased levels of ALT (alanine aminotransferase) and AST (aspartate aminotransferase) are key indicators of liver injury. These enzymes are typically found in the liver, and when liver cells are damaged, they release these enzymes into the bloodstream, resulting in elevated levels. This rise is commonly seen in conditions such as hepatitis, fatty liver disease, and liver cirrhosis.

Decreased levels of these enzymes would not indicate liver injury; rather, they might suggest a different underlying issue. Normal bilirubin levels would also not indicate liver injury, as elevated bilirubin is usually associated with liver dysfunction or bile duct obstruction. Increased BUN (blood urea nitrogen) and creatinine levels are markers typically associated with kidney function, not directly with liver injury. Therefore, the increase in ALT and AST is the most direct evidence of liver damage.