Evaluation of a New, Rapid Bedside Test for Quantitative Determination of B-Type Natriuretic Peptide

Abstract

Congestive heart failure (CHF) is among the most frequently encountered cardiac diagnoses, with an estimated prevalence of 1% (1). Plasma concentrations of B-type natriuretic peptide (BNP) and its precursor, N-terminal pro-BNP (NT pro-BNP), are increased in patients with CHF and have been shown to accurately predict clinical severity and left ventricular ejection fraction (LVEF) as well as morbidity and mortality in those patients (2)(3). A major limitation in the routine determination of natriuretic peptides is the time-consuming nature of analytical techniques, e.g., extraction procedures, long incubation times, or radioactive labeling (4)(5)(6)(7)(8). A rapid bedside test for determination of BNP was introduced recently (Triage BNP; Biosite Diagnostics, San Diego, CA). We evaluated the assay and compared it, in samples from patients with suspected CHF, with other assay systems for determination of either BNP (Shionoria BNP; CIS Diagnostics) or NT pro-BNP (Roche Diagnostics, Tutzing, Germany). The Triage BNP test is an immunofluorometric assay for quantitative determination of BNP in EDTA-anticoagulated whole blood or plasma (9)(10). A murine recombinant polyclonal antibody is bound to the fluorescent label, and a murine monoclonal antibody against the disulfide bond-mediated ring structure of BNP 32 is bound to the solid phase. Briefly, after the addition of 250 μL of EDTA-anticoagulated whole blood, the plasma is separated and allowed to react with fluorescent antibody conjugates within a reaction chamber. After an incubation period, complexes of the analyte and fluorescent antibody conjugates are captured on a detection lane. The concentration of BNP in the specimen is proportional to the fluorescence bound to the detection lane, which is determined quantitatively by a handheld fluorescence instrument (Triage Meter) as described in detail elsewhere (11 …