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

Abstract

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.

Keywords: ELISA; biomarker; dog; heart; overload; stretch.