Which laboratory test provides information about heart function in congestive heart failure?

B-type Natriuretic Peptide (BNP) testing is pivotal in assessing heart function, particularly in the context of congestive heart failure (CHF). When the heart struggles to pump blood effectively, as seen in CHF, the walls of the heart become stretched, leading to the release of BNP from the cardiac cells. Elevated levels of BNP indicate that the heart is under stress and not functioning properly, making it a key marker for diagnosing and managing CHF.

In clinical practice, measuring BNP levels helps differentiate between cardiac-related causes of dyspnea and those resulting from pulmonary or other non-cardiac issues, thus guiding treatment decisions.

The other tests mentioned serve different purposes: C-reactive Protein is a marker of inflammation rather than cardiac function, Cardiac Troponin is primarily used to diagnose myocardial infarction, and a Complete Blood Count (CBC) provides a broad overview of health but does not specifically assess heart function. Therefore, BNP is uniquely suited to evaluating heart performance in patients with congestive heart failure.