Access BNP II

The Access BNP II is a chemiluminescent immunoassay for quantitatively measuring B-type natriuretic peptide (BNP) in EDTA plasma using the Beckman Coulter Access Family of Immunoassay Systems. It is intended for diagnosing heart failure in emergency department patients, and for risk stratification in patients with acute coronary syndromes or heart failure.

The Access BNP II uses the same two-site immunoenzymatic sandwich assay format and chemiluminescent detection method as the predicate Access BNP assay. The new device operates on the DxI 9000 Access Immunoassay Analyzer (versus Access 2), uses a smaller sample volume (13 µL versus 55 µL), has a measuring range of 5–5,000 pg/mL (versus 1–5,000 pg/mL), and uses Lumi-Phos Pro substrate instead of Access Substrate.

CLSI EP05-A3 (precision), CLSI EP06-2nd Edition (linearity), CLSI EP07-3rd Edition (interference testing), CLSI EP17-A2 (detection capability), CLSI EP09c 3rd Edition (method comparison), CLSI EP24-A2 (diagnostic accuracy), CLSI EP12-A2 (qualitative test performance), CLSI EP25-Ed2 (reagent stability), CLSI EP28-A3c (reference intervals), and ISO 20916 (clinical performance studies).

The Access BNP II demonstrates substantial equivalence through method comparison showing excellent correlation (R=1.00) with the predicate device, successful imprecision and linearity studies meeting design specifications, absence of hook effects and significant cross-reactivity, and clinical data from 1,323 patients confirming a 100 pg/mL cutoff provides appropriate diagnostic sensitivity (93.1%) and specificity (65.6%) for heart failure diagnosis compared to clinical site diagnosis.