Which marker rises rapidly after myocardial infarction but is relatively nonspecific?

Which marker rises rapidly after myocardial infarction but is relatively nonspecific?

• A. Myoglobin
• B. Troponin
• C. Creatine kinase
• D. Lactate dehydrogenase

Answer: (A)

Rising rapidly after a myocardial infarction but relatively nonspecific describes myoglobin. Myoglobin is a small heme protein released from injured muscle cells, so its blood levels increase very early—often within 1–3 hours of the event—and peak around 6–9 hours. Because myoglobin is present in both cardiac and skeletal muscle, elevations can occur with other muscle injuries as well, making it nonspecific for heart injury. This quick rise makes it useful as an early screening marker, but its lack of specificity means it cannot confirm myocardial infarction on its own. For a more definitive assessment, cardiac-specific markers like troponin are preferred, though troponin rises later and remains elevated longer.

Rising rapidly after a myocardial infarction but relatively nonspecific describes myoglobin. Myoglobin is a small heme protein released from injured muscle cells, so its blood levels increase very early—often within 1–3 hours of the event—and peak around 6–9 hours. Because myoglobin is present in both cardiac and skeletal muscle, elevations can occur with other muscle injuries as well, making it nonspecific for heart injury. This quick rise makes it useful as an early screening marker, but its lack of specificity means it cannot confirm myocardial infarction on its own. For a more definitive assessment, cardiac-specific markers like troponin are preferred, though troponin rises later and remains elevated longer.