Considerable evidence exists to support the measurement of plasma B-type natriuretic peptides as an adjunct to clinical assessment, ECG, CXR, and echocardiography in patients with suspected heart failure.
Concentrations of natriuretic peptides are raised in patients with heart failure and increase in line with the severity of symptoms (New York Heart Association - NYHA class).
Currently they are best used as a "rule out " test for suspected heart failure as normal levels make a diagnosis of heart failure unlikely. BNP and NT Pro BNP are equally effective in their sensitivity to detect, and in their negative predictive value to exclude heart failure.
NICE guidance has recommended their role in the initial diagnosis of heart failure and an NT Pro BNP result > 2000pg/ml should be seen within two weeks. Please see www.nice.org.uk/guidance/CG108 and local guidance http://intra.cornwall.nhs.uk/DocumentsLibrary/RoyalCornwallHospitalsTrust/Clinical/Cardiology/ManagementOfChronicHeartFailureInPrimaryAndSecondaryCareInCornwall.pdf
In patients with symptoms suggestive of cardiac failure and a raised age specific Pro BNP < 2000pg/ml an outpatient ECHO should be considered.