Validation of a Bovine Viral Diarrhea Virus (BVDV) absolute quantification method by digital droplet PCR (ddPCR)

A increasingly common way for the diagnostics of viral agents is to carry out PCR from biological samples, which can detect their nucleic acid during the acute phase of the disease. Taking into account the need for quality control of PCR tests in laboratories accredited by ISO/IEC 17025:2017, we intend to carry out feasibility studies for the production of Reference Materials (MR) for these molecular tests, using BVDV in the matrix serum as a model. The first step for this goal was the validation of an analytical method for quantification of viral RNA to characterize the material under study. Primers and probe from a commercial qualitative assay kit designed for Real Time RT-PCR (VetMax Gold BVDV - Thermo Fisher) were used for quantification of BVDV by ddPCR. The technique was optimized and a Detection Limit of 13 copies/μL was determined, allowing a Quantification Limit of 38 copies/μL. The method showed to be linear over two orders of magnitude. The method will be used in the homogeneity study and long-term stability tests for the pilot batch of BVDV in Fetal Bovine Serum MR, a model for the production of MR intended for PCR of BVDV and other Flaviviridae .