What is the NT-proBNP test? NT-proBNP stands for N-terminal pro-B-type natriuretic peptide. It's a hormone produced in the heart. When the heart is under stress or working harder than usual, it releases more NT-proBNP into the bloodstream. What the NT-proBNP test is used for: The main use of the NT-proBNP test is to: Diagnose heart failure: Elevated levels of NT-proBNP can indicate that the heart isn't pumping blood as efficiently as it should. Assess the severity of heart failure: Higher levels generally indicate more severe heart failure. Monitor the effectiveness of heart failure treatment: Changes in NT-proBNP levels can help doctors track how well treatment is working. Distinguish between heart failure and other causes of shortness of breath: Such as lung problems.