B-type natriuretic peptide (BNP)

Brain natriuretic peptide, also called B-type natriuretic peptide (BNP), is a protein that the heart and blood vessels make. BNP helps the body eliminate fluids, relaxes blood vessels and moves sodium into the urine.

When the heart is damaged, the body secretes high levels of BNP into the bloodstream to try to ease the strain on the heart. One of the most important uses of BNP is to try to determine whether shortness of breath is due to heart failure.

BNP levels vary according to age, gender and weight. For people who have heart failure, establishing a baseline BNP can be helpful and future tests can be used to help measure how well treatment works.

A variation of BNP called N-terminal BNP is also useful for diagnosing heart failure and for evaluating the risk of a heart attack and other problems in those with existing heart disease.

A high level of BNP alone isn’t enough to diagnose a heart problem. Your health care provider will also consider your risk factors and other blood test results.