Performance characteristics of four automated natriuretic peptide assays

Measurement of circulating B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) can identify patients with heart failure and guide therapy. The limit of detection, linearity, imprecision, method comparison, analytic concordance, and reference intervals of the Access 2 BNP (Biosite, San Diego, CA), ADVIA Centaur BNP (Bayer Diagnostics, Tarrytown, NY), AxSYM BNP (Abbott Diagnostics, Abbott Park, IL), and El 70 NT-proBNP (Roche Diagnostics, Indianapolis, IN) methods were evaluated. The Triage meter BNP assay (Biosite) was the comparison method. Imprecision testing showed total coefficients of variation of 4.1%, 4.4%, 5.5%, and 0.8% for the Access 2, ADVIA Centaur, AxSYM, and El 70, respectively. Relative to the Triage meter, method comparison revealed a slope of 0.96 and r = 0.95, a slope of 0.77 and r = 0.92, a slope of 1.13 and r = 0.94, and a slope of 8.8 and r = 0.80 for the Access 2, ADVIA Centaur, AxSYM, and El 70, respectively. Overall analytic concordance values with the Triage meter were 95.9%, 92.9%, 92.4%, and 84.3% for the Access 2, ADVIA Centaur, AxSYM, and E170, respectively. All automated natriuretic peptide methods showed acceptable analytic performance.