A 55-year-old woman presents to the emergency department 6 hours after onset of chest pain. Which cardiac biomarker is the most specific for myocardial injury?
- A Myoglobin
- B Total creatine kinase
- C Cardiac troponin T ✓
- D Lactate dehydrogenase
Correct answer: C. Cardiac troponin T
Explanation
Cardiac troponins T and I are proteins almost exclusively expressed in cardiac muscle, so elevation is highly specific for myocardial injury. They rise within 2 to 4 hours, peak around 24 to 48 hours, and remain elevated for 7 to 10 days. Myoglobin rises even earlier but is abundant in skeletal muscle and lacks specificity. Total CK and LDH are also found in non-cardiac tissues, which kills them as candidates.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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