Which marker's sensitivity is high but specificity is low in detecting myocardial infarction?

Myoglobin is a protein that is released into the bloodstream when muscle tissue, including cardiac muscle, is damaged. Its sensitivity in detecting myocardial infarction is high because it can rise quickly after an injury to the heart, allowing for early detection of muscle damage. However, myoglobin's specificity is low because it is not exclusive to cardiac tissue; elevated levels can also result from damage to skeletal muscles, which can occur in a variety of other conditions unrelated to heart attacks. This means that while myoglobin can indicate that there is some form of muscle injury, it does not specifically pinpoint that the injury is due to myocardial infarction.

In contrast, although troponin is a more specific marker for myocardial injury, it is not as quick to rise as myoglobin. Creatinine is primarily a marker for kidney function, and B-type natriuretic peptide (BNP) is more associated with heart failure than with myocardial infarction specifically. Thus, myoglobin stands out in this context as a marker with high sensitivity but low specificity for myocardial infarction.