Evaluation of 2 commercial anti-SARS-CoV-2 antibody assays in an immunocompetent and immunocompromised inpatient population with COVID-19

Introduction: During the COVID-19 pandemic, widespread introduction of SARS-CoV-2 antibody testing was introduced without a full understanding of the assays performance or the antibody kinetics following infection with SARS-CoV-2. Methods: We performed an evaluation of 2 anti-SARS-CoV-2 antibody assays with a more detailed look into the effect of immune status on antibody sensitivity. Results: Both assays demonstrated 100% specificity. The overall sensitivity of the Roche was 92.1% at ≥14 days and 94.8% at ≥21 days, and the overall sensitivity of the Abbott was 94.4% at ≥14 days and 98.2% at ≥21 days. 7/41 (17%) of patients included in this cohort were immunocompromised. Seroconversion was seen less commonly in the immunocompromised (4/7 [57.1%] seroconverted) and after excluding these patients 100% sensitivity was seen in both assays at ≥21 days. Discussion: Performance of both assays in the immunocompetent appeared excellent after 21 days postsymptom onset. Both assays are highly specific.