Analytical validation of commercial immunoassays for the measurement of cardiovascular peptides in the dog

Immunoassays for the measurement of concentrations of the cardiovascular peptides pro-atrial natriuretic peptide (proANP), brain natriuretic peptide (BNPPen and BNPPhoe), endothelin-1 (ET-1Bio, ET-1IBL and ET-1Phoe) and big endothelin-1 (Big-ETBio and Big-ETIBL) were validated in canine serum by determination of intra-assay variability and dilutional parallelism. Commercial kits that showed good results were further validated by determination of intra- and inter-assay variability, dilutional parallelism and spiking recovery. Assays for proANP, BNPPhoe, ET-1IBL and Big-ETIBL showed acceptable results in the preliminary validation and were fully validated. The intra- and inter-assay variability was acceptable for all four assays, linearity was demonstrated and recovery rates were acceptable. The performances of the different immunoassays varied considerably, underscoring the importance of validation. Of the assays studied, proANP, BNP(Phoe), ET-1IBL and Big-ETIBL produced precise, reproducible and accurate results and can be recommended for clinical application.