NT-proBNP measurement on Immulite 2500 (DPC): analytical performance and comparison with Roche Diagnostics and Dade-Behring NT-proBNP immunoassays

The measurement of the N-terminal part of the proBNP (NT-proBNP) may be used to assess the secretion of the B-type natriuretic peptide (BNP), a marker of heart failure. In this study, we have evaluated the NT-proBNP immunoassay proposed by DPC Company for the Immulite 2500 analyzer and compared the results with those obtained with the two other immunoassays respectively commercialized by Roche Diagnostics (Elecsys 2010 analyzer) and Dade-Behring (Dimension RXL). The obtained results show very good general performance of the DPC's technique with a CV inferior to 8% for the values superior to 40 ng/L. The within run CVs are 3.1, 3.5 and 3.5% and the between run CVs are 3.8, 4.7 and 4.8% for the NT-proBNP levels of 151, 1601 and 5255 ng/L, respectively. We found a very good correlation between DPC's and Roche Diagnostics's assays (regression analysis: y = 0.88 x + 25.2 ; r = 0.998) and DPC's and Dade-Behring assays (regression analysis: y = 0.93 x + 16.4 ; r = 0.997). Although a small bias appeared between these assays, similar cut-points may be used to exclude both heart failure in ambulatory patients and cardiac origin in acute dyspnea.