Adult Critical Care Specialty (ACCS) Practice Exam

Given the patient data presented, which test should be ordered to confirm suspected congestive heart failure?

1. Troponin

2. Brain natriuretic peptide

3. Magnesium level

4. MB fraction of creatinine phosphokinase

The correct answer is: Brain natriuretic peptide

The test that should be ordered to confirm suspected congestive heart failure (CHF) is Brain natriuretic peptide (BNP). BNP is a hormone produced by the heart in response to increased pressure that often occurs when heart failure develops or worsens. Elevated levels of BNP in the blood indicate that the heart is under stress and not functioning efficiently, which is a hallmark of congestive heart failure. When CHF is suspected clinically, measuring BNP levels is a valuable diagnostic tool. It helps differentiate heart failure from other conditions presenting with similar symptoms, such as pulmonary disease. In addition, BNP levels correlate with the severity of heart failure, providing vital information for treatment decisions. Troponin tests are primarily used to diagnose myocardial infarction and assess cardiac injury, making them less specific for CHF. Magnesium levels are generally assessed in situations where electrolyte imbalances could affect cardiac function, but they do not specifically confirm heart failure. The MB fraction of creatinine phosphokinase is related to cardiac damage, but similar to troponin, it does not provide confirmation of heart failure itself. Thus, BNP is the most appropriate test for confirming suspected congestive heart failure.