Question

Which of the following is the most sensitive marker for myocardial infarction in the first 6 hours after symptom onset?

• A. CK-MB
• B. Troponin I
• C. Myoglobin
• D. LDH

Hint:

In acute coronary syndromes, remember the timeline of cardiac markers: myoglobin first, then troponins for specificity.

Answer 1

The Correct Option is C

Step 1: Understanding the question.
The question asks for the most sensitive marker for myocardial infarction within the first 6 hours. Myoglobin rises quickly after cardiac injury, making it sensitive in the early phase.
Step 2: Analyzing the options.
(A) CK-MB: CK-MB rises after 4-6 hours but is not the earliest.
(B) Troponin I: Troponin I is highly specific but rises after 3-6 hours.
(C) Myoglobin: Correct — Myoglobin is the earliest marker, rising within 1-3 hours.
(D) LDH: LDH rises much later, after 24 hours.
Step 3: Conclusion.
The correct answer is (C) Myoglobin, as it is the most sensitive marker in the first 6 hours after myocardial infarction.