In acute myocardial infarction, cardiac troponin I begins to rise in serum at which time interval after symptom onset?
- A 1 to 2 hours
- B 3 to 4 hours ✓
- C 6 to 12 hours
- D 24 to 48 hours
Correct answer: B. 3 to 4 hours
Explanation
Cardiac troponin I rises within 3 to 4 hours of myocardial injury, peaks at 12 to 48 hours, and remains elevated for 7 to 10 days. This makes it superior to CK-MB for early diagnosis. CK-MB rises at 3 to 4 hours but troponin is the preferred biomarker due to higher specificity. Myoglobin rises earliest at 1 to 2 hours but lacks cardiac specificity. LDH and AST are outdated markers that rise later (12 to 24 hours) and are no longer recommended.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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