Which statement is true regarding serum enzymes?

Which statement is true regarding serum enzymes?

• A. The presence of hemolyzed red cells is of no significance for an accurate assay of most serum enzymes.
• B. Serum AST, but not serum LD, is usually elevated in acute myocardial infarction.
• C. Increased serum alkaline phosphatase may be found in bone disease.
• D. Aspartate transaminase was formerly known as glutamate pyruvate transaminase.

Answer: (C)

Serum enzyme levels reflect the tissue sources and turnover of specific enzymes. Alkaline phosphatase is produced in bone and liver, and when there’s increased osteoblastic activity in bone diseases, total serum ALP often rises. This makes the statement about bone disease true: elevated ALP can accompany bone conditions such as Paget disease, osteomalacia, or other high-turnover states, reflecting increased bone formation activity. Nonessential details about the other options help reinforce why this one is correct. Hemolyzed samples release intracellular enzymes into serum, which can falsely raise enzyme activities, so saying hemolysis is insignificant is not accurate. In myocardial infarction, both AST and LD levels can rise, so claiming only AST increases isn’t correct. Finally, AST was historically called glutamate oxaloacetate transaminase, while GPT (glutamate pyruvate transaminase) was the name for ALT, so the naming in that option is not correct.

Serum enzyme levels reflect the tissue sources and turnover of specific enzymes. Alkaline phosphatase is produced in bone and liver, and when there’s increased osteoblastic activity in bone diseases, total serum ALP often rises. This makes the statement about bone disease true: elevated ALP can accompany bone conditions such as Paget disease, osteomalacia, or other high-turnover states, reflecting increased bone formation activity.

Nonessential details about the other options help reinforce why this one is correct. Hemolyzed samples release intracellular enzymes into serum, which can falsely raise enzyme activities, so saying hemolysis is insignificant is not accurate. In myocardial infarction, both AST and LD levels can rise, so claiming only AST increases isn’t correct. Finally, AST was historically called glutamate oxaloacetate transaminase, while GPT (glutamate pyruvate transaminase) was the name for ALT, so the naming in that option is not correct.