Which substance rapidly rises in the bloodstream in the presence of heart failure and is a good diagnostic test?

B-type natriuretic peptide (BNP) is a hormone produced primarily by the ventricles of the heart in response to ventricular volume expansion and pressure overload, conditions commonly seen in heart failure. When the heart is unable to pump effectively, as in heart failure, BNP levels rise significantly in the bloodstream. This makes it an important biomarker for diagnosing and assessing the severity of heart failure.

BNP testing helps distinguish between cardiac and non-cardiac causes of dyspnea since elevated levels indicate that heart failure is likely contributing to the patient's symptoms. Moreover, BNP levels can be used to monitor the response to treatment in heart failure patients, making it a valuable tool in clinical practice.

Other substances listed, such as C-reactive protein (CRP), serum albumin, and erythrocyte sedimentation rate (ESR), are more general markers of inflammation or other systemic conditions rather than specific indicators of heart failure. Their roles are not focused on cardiac function, thus making them less effective for diagnosing heart failure compared to BNP.