Clinical validation and performance evaluation of the automated Vitros Total Anti-SARS-CoV-2 Antibodies assay for screening of serostatus in COVID-19

Objectives Evaluation of serostatus against SARS-CoV-2 has emerged as an important tool in identification of exposure to COVID-19. We report on the validation of the Vitros Anti-SARS-CoV-2 Total (CoV2T) assay for qualitative serological testing of SARS-CoV-2 antibodies. Methods We performed validation studies according to COLA guidelines, using samples previously tested for SARS-CoV-2 by RT-PCR. We evaluated precision, analytical interferences, and cross-reactivity with other viral infections. We also evaluated concordance with molecular and other serological testing, and evaluated seroconversion. Results The Vitros CoV2T assay exhibited acceptable precision, was resistant to analytical interference, and did not exhibit cross-reactivity with samples positive for other respiratory viruses. The CoV2T assay exhibited 100% negative predictive agreement (56/56) and 71% positive predictive agreement (56/79) with RT-PCR across all patient samples, and was concordant with other serological assays. Concordance with RT-PCR was 97% > 7 days after symptom onset. Conclusions The Vitros CoV2T assay was successfully validated in our laboratory. We anticipate it will be a useful tool in screening for exposure to SARS-CoV-2, however, the use of the CoV2T and other serological assays in clinical management of COVID-19 patients is yet unknown, and must be evaluated in future studies. Key points What issue or core problem does the study address? Multiple serological assays for detection of anti-SARS-CoV-2 antibodies have received FDA Emergency Use Authorizations, but few data have been published on the performance of these assays. What would one take-home point for the working medical professional be? The Vitros Anti-SARS-CoV-2 Total assay is a total antibody test to be used as a serological screen for exposure to COVID-19. This assay performs well, and is comparable to other serological tests. What is the most significant or most interesting finding of the study? We confirmed that the Vitros Anti-SARS-CoV-2 Total assay, like other serological tests, is not suitable for diagnosis of acute infection, as it is not sensitive to infection <7 days post-onset.