Use of a solid-phase extraction with radioimmunoassay to identify the proportional bias of clinical B-type natriuretic peptide immunoassay: the impact of plasma matrix and antibody multispecificity.

Background: Circulating immunoreactive B-type natriuretic peptide-32 (ir-BNP-32) has diagnostic and prognostic values in heart failure. We compared, in parallel, a point-of-care (POC) test (Triage((R)) BNP Test) of whole plasma and radioimmunoassay (RIA) of solid-phase extracted (SPE) plasma (SPE/RIA) utilizing a novel copolymer column, in the measurement of patient ir-BNP-32 concentrations.

Methods: Approximately 0.