If ALT is elevated with a normal ALP, which pattern is most likely and what does it indicate about liver injury?

• A. A predominance of ALT with normal ALP suggests hepatocellular injury.
• B. A predominance of ALP with normal ALT suggests cholestasis.
• C. ALT elevated with ALP elevated indicates mixed injury.
• D. Normal ALT and ALP excludes liver injury.

Answer: (A)

The key idea is how patterns of liver enzyme elevations differentiate hepatocellular injury from cholestasis. ALT is a hepatocyte enzyme that leaks into the blood when liver cells are damaged, whereas alkaline phosphatase comes from the bile ducts and rises with cholestasis or biliary obstruction. When ALT is elevated with a normal ALP, the signal is that hepatocytes are primarily injured rather than the bile ducts. This pattern is typical of hepatocellular injury from causes like viral hepatitis, drug-induced damage, or ischemia, where cytosolic enzymes spill into the bloodstream but the biliary tract isn’t obstructed. If ALP were elevated with normal ALT, that would point toward cholestasis; if both were raised, a mixed or more extensive injury could be present. A normal ALT and ALP generally suggests no active hepatocellular or cholestatic injury.