Development and calibration of a new point-of-care test for the determination of NT-proBNP in whole blood.

A new point-of-care test for the determination of NT-proBNP in whole blood was developed based on the existing gold-label rapid immunoassay technology of the Roche Cardiac reader system. The novel gold-labelled monoclonal antibody recognizes NT-proBNP at amino acid sequence 27 to 31, the biotinylated polyclonal antibody recognizes sequence 39 to 50. In a model assay based upon the reference method Elecsys proBNP and with an R & D lot of the point-of-care test, this newly selected and developed combination of antibodies showed a very good correlation with the standard Elecsys proBNP assay with correlations of 0.96 or 0.94, respectively. The test was calibrated according to the existing masterlot concept of the Roche CARDIAC tests with Elecsys proBNP as a reference. In a preliminary method comparison with Elecsys proBNP the accuracy of the calibration was confirmed; the bias was between 1 and 6%. Possible reasons of approximately 1% outliers (> +/- 100%) were discussed.