Analytical validation of a novel point‐of‐care immunoassay for canine N‐terminal pro‐brain natriuretic peptide analysis

BACKGROUND: N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) is a widely used point‐of‐care (POC) cardiac biomarker in human medicine. Canine NT‐proBNP is used less in veterinary medicine, possibly due to the lack of a POC canine NT‐proBNP assay resulting in temporal delay, increased degradation in transport, and high reported variability in the available assay. A new quantitative POC analyzer allows fast, onsite measurement of NT‐proBNP, minimizing preanalytical error and reducing variability. OBJECTIVE: We aimed to analytically validate an NT‐proBNP assay (Vcheck) according to American Society of Veterinary Clinical Pathology (ASVCP) and Clinical Laboratory Improvement Amendments (CLIA) specifications. METHODS: Archived and prospective plasma and serum samples were collected from male and female, client‐owned dogs of various breeds with cardiac abnormalities (n = 81) and a healthy control population (n = 225). Precision, accuracy, analytical sensitivity, and specificity, and other statistical analyses were performed. RESULTS: Imprecision was considered acceptable with a coefficient of variation ranging from 9% at 4000 pmol/L to 20% at 600 pmol/L. The lower limit of quantitation was 650 pmol/L based on repetitive measures evaluation. Comparison of the Vcheck assay with the Cardiopet NT‐proBNP assay revealed an excellent correlation with minimal bias when preanalytical factors were controlled. Significant degradation of NT‐proBNP occurred when current methods were used at refrigerated and room temperatures, which could change diagnostic and prognostic decision‐making. Age‐partitioned reference intervals have high reference values of 750 pmol/L and 1280 pmol/L for juvenile and adult dogs, respectively. CONCLUSIONS: The Vcheck NT‐ProBNP assay provides analytically acceptable results. Onsite testing can minimize variability related to preanalytical error and provide clinically useful contemporaneous results. Samples should be centrifuged immediately and analyzed within 2 hours of collection.