Fully automated dried blood spot sample handling and extraction for BoHV-1 antibody testing by ELISA

This study is the first proof of concept of the DBS technology for Bovine alphaherpesvirus 1 (BoHV-1) antibody detection by ELISA after fully automated DBS extraction. DBS were prepared from nine BoHV-1 seropositive plasma samples spiked with erythrocytes. Spots were extracted automatically on a DBS-MS 500 HCT autosampler, as well as manually using a 3.2 mm puncher. DBS were equally prepared from 20 bovine seronegative EDTA-blood samples and extracted automatically. Extracts were tested in a commercial BoHV-1 antibody ELISA and results were compared with those from liquid plasma. Eight seropositive DBS samples were additionally tested in the ELISA after storage for four weeks at different conditions. After automated extraction all DBS samples yielded qualitatively correct results and were in full accordance with those obtained from liquid plasma. Automated extraction using a 6 mm extraction head was more sensitive than a 4 mm head. Stability of DBS was highest at - 20 °C and decreased with increasing temperature. Even after four weeks at 37 °C, most seropositive samples yielded a positive result in the ELISA. The minimal invasiveness, biosafety, and simplicity of DBS collection together with automated extraction represents an interesting, high-throughput compatible alternative to liquid blood samples for BoHV-1 monitoring or eradication programs.