National Academy of Clinical Biochemistry and IFCC Committee for Standardization of Markers of Cardiac Damage Laboratory Medicine Practice Guidelines: Analytical Issues for Biomarkers of Heart Failure

### A. Background In 2005, the IFCC C-SMCD recommended analytical and pre-analytical quality specifications for natriuretic peptide and their related co-metabolites assays.1 The objectives developed were intended to guide manufacturers of commercial assays and clinical laboratories that utilize these assays. The overall goal was to establish uniform criteria so that the analytical qualities and clinical performance of assays natriuretic peptide and their related co-metabolites could be evaluated objectively. As B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) become more heavily integrated into clinical practice as diagnostic and prognostic biomarkers, understanding the differences between individual assays becomes important. Further, the influence of clinical, analytical and preanalytical factors on the growing number of BNP and NT-proBNP assays commercially available begs for a better understanding of how to interpret findings of different studies predicated on BNP or NT-proBNP concentrations monitored by different assays. The Laboratory Medicine community must also work closely with the in vitro diagnostics companies to assist in defining all of the assay characteristics,1 a process that was poorly orchestrated during the developmental phase of cardiac troponin assays. When BNP or NT-proBNP assays are used as biomarkers for diagnosis, therapy decisions, and prognosis, or used in clinical trials or studies, they should be well characterized, as suggested by the list of recommendations that follow. We recommend that when designing studies that will use BNP or NT-proBNP assays, investigators …