Comparison of the Biomedica NT-proBNP enzyme immunoassay and the Roche NT-proBNP chemiluminescence immunoassay: implications for the prediction of symptomatic and asymptomatic structural heart disease.

Abstract

The amino-terminal fragment of the B-type natriuretic peptide prohormone (NT-proBNP) is a marker for functional cardiac impairment and is increased in heart disease with or without symptoms of heart failure (HF) (1). There are indications that currently used assays for NT-proBNP may differ in their cross-reactivity with circulating NT-proBNP split products and may also be affected by breakdown products of NT-proBNP produced after blood collection (2). A newer generation assay, a commercially available competitive enzyme immunoassay (EIA) for NT-proBNP (Biomedica Gruppe) (3) that does not require sample pretreatment, has been used in various methodologic and clinical studies (4)(5)(6), but noncompetitive immunoassays may offer advantages of better speed, sensitivity, precision, and possibly specificity over competitive immunoassays (7). Recently, a noncompetitive immunoassay for NT-proBNP has been developed (8). A fully automated version of this assay (Roche Diagnostics) has now been cleared by the US Food and Drug Administration. Our aim was to compare the Biomedica and Roche NT-proBNP assays, addressing whether the predictive values of both assays are similar with respect to structural heart disease with or without symptoms of HF. The present study, carried out at the Division of Internal Medicine, St. John of God Hospital (Linz, Austria), was approved by the local ethics committee in accordance to the Helsinki Declaration. We prospectively recruited 157 consecutive patients admitted for extensive cardiac evaluation (including performance of bicycle ergometry) and 23 consecutive patients with symptomatic HF admitted for inpatient treatment; all participants gave written informed consent. Study participants were classified according to the American College of Cardiology/American Heart Association guidelines for the evaluation and management of chronic HF in the adults (9) to one of the four following categories: ( a ) healthy individuals (n = 42); ( b ) patients at high risk for developing HF but without structural disorders of the …