Brain natriuretic peptide (BNP), now known as B-type natriuretic peptide or Ventricular Natriuretic Peptide (still BNP), is a 32-amino acid polypeptide secreted by the ventricles of the heart in response to excessive stretching of heart muscle cells (cardiomyocytes). The release of BNP is modulated by calcium ions

The main clinical utility of either BNP or NT-proBNP is that a normal level rules out acute heart failure in the emergency setting. An elevated BNP or NT-proBNP should never be used to “rule in” acute or heart failure in the emergency setting due to lack of specificity.It appears to have become a common misconception in many emergency departments that ordering brain natriuretic peptide studies in a routine manner has reliable positive predictive value (PPV). However, the value of the test in terms of PPV has simply not been shown. Using these studies inappropriately in such a way would likely result in increased healthcare costs, however an extensive study regarding the potential cost has yet to be performed.