BNP test is a blood test conducted to measure the levels of two proteins called B-type natriuretic peptide and N-terminal-pro-BNP. The levels of both these proteins get elevated in patients with heart failure. This test will guide your doctor to make a diagnosis of heart failure. It may also show how the condition has deteriorated since your last visit and will allow him to formulate an effective treatment strategy. You will be required to provide a small amount of blood which is placed in a machine that measures the protein levels. Your doctor will discuss the results with you along with the treatment recommendations.