Whether antibody levels measured by commercially available enzyme or chemiluminescent immunoassays targeting the SARS-CoV-2 spike (S) protein can act as a proxy for serum neutralizing activity remains to be established for many of these assays. We evaluated the degree of correlation between neutralizing antibodies (NtAb) binding the SARS-CoV-2 spike (S) protein and SARS-CoV-2-S-IgG levels measured by four commercial immunoassays in sera drawn from hospitalized COVID-19 patients. Ninety sera from 51 hospitalized COVID-19 patients were tested by a pseudotyped virus neutralization assay, the LIAISON SARS-CoV-2 S1/S2 IgG, the Euroimmun SARS-CoV-2 IgG ELISA, the MAGLUMI 2019-nCoV IgG, and the COVID-19 ELISA IgG assays. Overall, the results obtained with the COVID-19 ELISA IgG test showed the highest agreement with the NtAb assay (κ, 0.85; 95% CI, 0.63–1). The most sensitive tests were the pseudotyped virus NtAb assay and the COVID-19 ELISA IgG assay (92.2% for both). Overall, the degree correlation between antibody titers resulting in 50% virus neutralization (NtAb₅₀) in the pseudotyped virus assay and SARS-CoV-2 IgG levels was strong for the Euroimmun SARS-CoV-2 IgG ELISA (rho = 0.73) and moderate for the remaining assays (rho = 0.48 to 0.59). The kinetic profile of serum NtAb₅₀ titers could not be reliably predicted by any of the SARS-CoV-2 IgG immunoassays. The suitability of SARS-CoV-2-S-IgG commercial immunoassays for inferring neutralizing activity of sera from hospitalized COVID-19 patients varies widely across tests and is influenced by the time of sera collection after the onset of symptoms.

对于许多这些检测方法，通过商业上可用的酶或化学发光免疫测定法测量的针对 SARS-CoV-2 刺突 (S) 蛋白的抗体水平是否可以作为血清中和活性的代表仍有待确定。我们评估了结合 SARS-CoV-2 刺突 (S) 蛋白的中和抗体 (NtAb) 与 SARS-CoV-2-S-IgG 水平之间的相关程度，这些水平是通过四种商业免疫测定法对来自住院 COVID-19 患者的血清进行测量的。来自 51 名住院 COVID-19 患者的 90 份血清通过假型病毒中和试验、LIAISON SARS-CoV-2 S1/S2 IgG、Euroimmun SARS-CoV-2 IgG ELISA、MAGLUMI 2019-nCoV IgG 和 COVID -19 ELISA IgG 检测。总体而言，通过 COVID-19 ELISA IgG 测试获得的结果与 NtAb 检测的一致性最高（κ , 0.85; 95% CI，0.63–1)。最敏感的检测是假型病毒 NtAb 检测和 COVID-19 ELISA IgG 检测（两者均为 92.2%）。总体而言，Euroimmun SARS-CoV-2 IgG ELISA (rho = 0.73) 和中度相关性在假型病毒测定中导致 50% 病毒中和 (NtAb ₅₀ ) 的抗体滴度与 SARS-CoV-2 IgG 水平之间的相关程度很强对于其余的测定（rho = 0.48 至 0.59）。血清 NtAb _{50的动力学特征}任何 SARS-CoV-2 IgG 免疫测定都无法可靠地预测滴度。SARS-CoV-2-S-IgG 商业免疫测定法用于推断住院 COVID-19 患者血清的中和活性的适用性在不同测试中差异很大，并受症状出现后血清采集时间的影响。