Cardiac natriuretic hormones: methodological aspects

It is known the important role of cardiac natriuretic hormones (CNH) assay (especially BNP) in screening for heart disease, detection of left ventricular dysfunction, differential diagnosis of dyspnea and prognostic stratification of patients with congestive heart failure. CNH can be measured with competitive or non-competitive immunoassays. Noncompetitive immunoassays share better degree of sensitivity, precision and specificity than the respective competitive immunoassays. Recently, a new generation of fully automated immunoassays, for BNP and NT-proBNP, became commercially available. They are noncompetitive sandwich-type immunoassays which uses non-radioactive materials as labels for antigen/antibody reaction and two monoclonal antibodies (or a combination of monoclonal and polyclonal) for peptide binding. Although these assays produce results in a short time and with excellent analytical imprecision, the BNP/NT-proBNP values continue to significantly depend on the type of assay used, as a result of the specificity of the employed antibodies and of different analytical standardization deriving from the different calibration materials.