Figure 2.

Screening for the presence of severe acute respiratory syndrome coronavirus 2 antibodies in plasma from coronavirus disease 2019 (COVID-19)–positive subjects (COVID-19 pos.) and from plasma derived from the general blood bank plasma inventory (COVID-19 neg.). Assays were run using the S protein produced in mammalian cells: mSpike (left) and mRBD (right). Results are shown using plasma tested at a dilution of 1:200. Statistical analysis using the Mann–Whitney test is shown. Medians with error bars representing standard deviation are indicated. Abbreviations: COVID-19, coronavirus disease 2019; MFI, mean fluorescence intensity; mRBD, mammalian-derived Receptor Binding Domain polypeptide; mSpike, mammalian-derived Spike protein.