Adult Critical Care Specialty (ACCS) Practice Exam

Which lab test is most effective in confirming a myocardial infarction?

1. PvO2

2. Phosphate

3. Troponin

4. Lactate

The correct answer is: Troponin

Troponin is a protein that is released into the bloodstream when the heart muscle is damaged, making it a highly specific biomarker for myocardial infarction (MI). In the context of a heart attack, the levels of troponin in the blood rise due to the injury to cardiac myocytes. Testing for troponin is integral to the diagnosis of an MI, as it not only confirms the presence of myocardial necrosis but also helps to assess the severity and timing of the event. The rise and fall pattern of troponin levels can indicate the timing of the infarction, distinguishing between a recent event and older injuries. In clinical practice, troponin tests are routinely used in emergency departments and critical care settings due to their high sensitivity and specificity for cardiac injury. Other lab tests like PvO2, phosphate, and lactate have roles in the assessment of various conditions but do not provide the same definitive confirmation of myocardial infarction as troponin does. PvO2 is more related to oxygenation status, phosphate levels can reflect metabolic derangements, and lactate is typically assessed in cases of tissue hypoxia and sepsis rather than specifically for the diagnosis of MI. Therefore, troponin stands out as the most effective and