Doctors use B-type natriuretic peptide, or BNP, blood testing to monitor the progression of heart failure, according to Cleveland Clinic. The ventricles of the heart secrete BNP in response to the development and worsening of heart failure, making the test useful in monitoring heart failure patients and devising treatment plans.
BNP levels of 100 to 300 picograms per milliliter suggest the presence of heart failure, while levels greater than 300 picograms per milliliter suggest mild heart failure, notes Cleveland Clinic. Levels of 600 picograms per milliliter are indicative of moderate heart failure, and BNP levels greater than 900 picograms per milliliter indicate severe heart failure. Doctors also use BNP testing to confirm heart failure during the diagnostic process.