State of the art of BNP and NT-proBNP immunoassays: The CardioOrmoCheck study

► BNP assay is considered a reliable test for the evaluation of cardiac function. ► Guidelines recommend an identical decision level for all BNP immunoassays. ► We organized a proficiency study to compare the results of these immunoassays. ► Marked differences in analytical performance and measured values were demonstrated. ► Therefore different decision values should be adopted for BNP immunoassay methods.