5 Evaluating the Clinical Performance of FDA-Approved Alere NT-proBNP

Introduction N-terminal pro B-type natriuretic peptide (NT-proBNP) and B-type natriuretic peptide (BNP) are biomarkers for the diagnosis and monitoring of heart failure. Both biomarkers originate from the same precursor molecule, proBNP, which is synthesized from preproBNP when ventricular or atrial diastolic wall is stretched. BNP is the biologically active peptide, while NT-proBNP is the inactive peptide that is released together with BNP in myocardial stretch. NT-proBNP has a half-life of about 70 minutes, while BNP has about 20 minutes, which makes NT-proBNP a preferred biomarker. This study evaluated the performance of the Abbott Alere NT-proBNP assay by comparing it quantitatively and qualitatively with our current RAMP NT-proBNP and Architect BNP assays. Methods A qualitative comparison was performed between Abbott NT-proBNP and Abbott BNP using 40 patient samples with BNP orders. A separate quantitative comparison was performed between two NT-proBNP platforms: RAMP and Alinity, using 173 patient samples from three community hospitals. The agreement between RAMP and Alinity NT-proBNP assays was assessed using Passing-Bablok regression analysis. Results A 2x2 table showed 100% clinical agreement between the Alinity NT-proBNP and the Architect BNP using age and gender-specific reference intervals for each biomarker. In the quantitative assessment, a Passing–Bablok regression plot showed strong agreement between the Alinity and RAMP NT-proBNP for samples under 6000 pg/mL (slope = 1.080; intercept = -6.190). The data showed excellent agreement between the Alinity and RAMP NT-proBNP assays at concentrations under 6000 pg/mL. Conclusions The Alinity NT-proBNP assay showed complete qualitative agreement with the Architect BNP assay using age and sex-specific reference intervals. Quantitatively, Alinity and RAMP NT-proBNP results were comparable, but a proportional bias was observed in the Alinity assay at concentrations higher than 6000 pg/mL.