Fig. 2. Specificity of the ARCHITECT^® SARS-CoV-2 IgG assay for COVID-19 diagnosis. IgG assay plot of cases and controls, including non-COVID-19 cases and cases not suspected to be COVID-19. “Non-COVID-19”: non-COVID-19 samples collected at Toho University Omori Medical Center and the National Hospital Organization Tokyo Medical Center between March and May 2020; “COVID-19 unsuspected”: samples not suspected of COVID-19 collected at Toho University Omori Medical Center; “JRC pre-COVID-19 outbreak”: blood donation samples provided by the Japanese Red Cross Society. Three IgG assay-positive samples collected at Toho University Omori Medical Center, which were non-COVID-19, were collected from one patient (case 65). The dashed line indicates the IgG assay cutoff value (index=1.40).
Abbreviations: SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; COVID-19, Coronavirus disease 2019; JRC, Japanese Red Cross Society.

Ann Lab Med 2021;41:568~576 https://doi.org/10.3343/alm.2021.41.6.568