2022 Volume 71 Issue 3 Pages 523-527
We examined the possible use of anti-SARS-CoV-2 antibody reagents for identifying previously infected persons. The reagents were Elecsys Anti-SARS-CoV-2 RUO (Roche Diagnostics K.K. (C)), ARCHITECT SARS-CoV-2 IgG (Abbott Japan LLC (A-G)), and SARS-CoV-2 IgM (Abbott Japan LLC (A-M)). Conservative samples from 16 SARS-CoV-2-positive patients and nine SARS-CoV-2-negative patients determined by the SARS-CoV-2PCR test conducted from February to October 2020 were used in the reagent examination. As a result, 13 of the 16 patients who were SARS-CoV-2-positive by the PCR test were confirmed to be positive (sensitivity 81.3%) using C, and 14 patients were confirmed to be SARS-CoV-2-positive (sensitivity 87.5%) using A-G and A-M. On the other hand, in the nine patients that were SARS-CoV-2-negative by the PCR test, all three reagents gave a negative result (specificity 100%). C/A-G is an antibody to the nucleocapsid protein and can detect IgG. A-M is an antibody to the spike protein and can detect IgM. Because the number of cases was limited, results showed no significant difference in the type of protein of interest and IgG/IgM, and the patients who were not found SARS-CoV-2-positive by the PCR test were confirmed to be so using all three reagents. Since C/A-G is detected even long after infection, it can possibly be used for the determination of past infection. A-M needs to be examined for the effect of the vaccine.
