Dot-blot ELISA assay demonstrates strong agreement with hemagglutination inhibition for the detection of canine parvovirus antibodies in sera of healthy, vaccinated blood-donor dogs

Abstract Objective To compare canine parvovirus (CPV) antibody titers in sera of community blood-donor dogs using the hemagglutination inhibition (HI) assays from 2 state veterinary diagnostic laboratories (VDLs) and a dot-blot ELISA assay to determine intermethod agreement. Methods Stored sera (–80-°C freezer) from 100 healthy community-based blood-donor dogs were selected. Dogs represented various breeds and ages. Available vaccination history was retrospectively assessed. Sera were thawed and delivered to the VDLs, with HI and the dot-blot ELISA assay performed the following day. Results Of 100 samples, 96 dot-blot ELISA results were within a 2-fold dilution of the corresponding HI titer from the Colorado State University VDL, and 92 were within a 2-fold dilution of the HI titer from the New York State VDL. The dot-blot ELISA assay demonstrated high sensitivity (96% and 97%) and strong agreement (Spearman ρ = 0.72 and 0.92). Of 43 dogs with vaccination history, 93% had protective titers. The 3 lowest titers occurred in dogs vaccinated within 1 year. Conclusions CPV antibody titers in community blood-donor dogs showed strong agreement between HI assays and the dot-blot ELISA assay. A high concordance and strong correlation support the dot-blot ELISA assay as a reliable method for estimating CPV antibody titers. Clinical Relevance Accurate, rapid assessment of CPV titers is important for selecting plasma from community blood-donor dogs intended for passive immunotherapy in critically ill parvoviral patients. Demonstration of strong agreement between the dot-blot ELISA and reference HI assays supports the use of this assay for in-house donor screening and timely plasma selection.