Which serum biomarker is the first to rise after onset of myocardial infarction but lacks specificity for cardiac injury?
- A Cardiac troponin I
- B Myoglobin ✓
- C CK-MB
- D LDH
Correct answer: B. Myoglobin
Explanation
Myoglobin is released within 1 to 2 hours of myocardial injury, earlier than any other marker, but it is abundant in skeletal muscle so it cannot distinguish cardiac from skeletal muscle damage. Troponin I rises within 2 to 4 hours and is the most specific and clinically used marker, CK-MB rises around 4 hours and helps detect reinfarction, and LDH peaks only after several days and is obsolete for acute diagnosis.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.