Which serum protein rises earliest after myocardial cell injury?

The rise of troponin levels in the serum is a key indicator of myocardial cell injury, and it is considered the most sensitive and specific marker for myocardial infarction. When heart tissue is damaged, troponin, a protein found in cardiac muscle, is released into the bloodstream. This release occurs swiftly and can often be detected within a few hours after the onset of myocardial injury.

Troponin levels can remain elevated for an extended period, which adds to its diagnostic value in confirming a recent heart attack, even if some time has passed since the injury occurred. This characteristic ensures that troponin is a preferred marker in clinical settings for diagnosing acute myocardial infarction.

Other markers like creatine kinase and LDH can also indicate myocardial injury, but they do not rise as quickly as troponin. Myoglobin, although it may rise earlier than some other markers, lacks specificity for cardiac tissue, as it can also be elevated in skeletal muscle injury. This makes troponin the best choice among the options provided for identifying myocardial cell injury in its earliest stages.