A-278 Development and Validation of Platform Independent, Turbidimetric Sars-CoV-2 Total Antibody Assay

Abstract

Abstract Background The outbreak of the SARS-CoV-2 pandemic and continuous presence of the virus in the community require efficient tests for monitoring the anti-SARS-CoV-2 levels and management of the vaccination response in the population. Gentian AS, in collaboration with the University of Tromsø, has developed a quantitative SARS-CoV-2 antibody assay that captures the full immune response detecting antibodies targeting the S1-subunit with high sensitivity and specificity and is calibrated against the WHO international standard. Methods The immunoassay was developed and validated on turbidimetric instruments Cobas c501 from Roche and BS240 BS/240Pro from Mindray. Pre-pandemic samples from healthy donors or patients, were used for evaluation of clinical specificity. Samples from patients infected with Sars-CoV-2 virus or vaccinated against the virus were used for evaluation of clinical sensitivity. Results The assay has a calibration range from 0 to 1000 BAU/mL. No antigen excess was observed up to 2500 BAU/mL. Precision achieved a CV <20 % for samples with a concentration ≤ 165 BAU/mL, and <10 % for samples >165 BAU/mL. No clinically relevant cross reactivity towards 13 antibodies, including antibodies against other Corona viruses was observed. The assay was able to detect antibodies generated in response to different vaccines and Alpha, Beta, Gamma, Delta and Omicron virus variants. Sensitivity and specificity of the assay met the acceptance criteria set out from the MDCG 2021–21 guideline, ≥90% and >99% respectively. Conclusion The Gentian SARS-CoV-2 total antibody assay is a platform independent high-throughput assay with high sensitivity and specificity for assessment of antibody response after a natural infection and/or vaccination. The assay can ensure effective and reliable monitoring of the immunity and can be used for planning and management of the vaccination response in the community.