Ivana Lapić, Department of Laboratory Diagnostics, University Hospital Center Zagreb, Kišpatićeva 12, 10000 Zagreb, Croatia,
Croat Med J. 2020 Dec 31;61(6):485-490. doi: 10.3325/cmj.2020.61.485.
To evaluate three fully automated serological assays in terms of reactivity to SARS-CoV-2 immunoglobulin G (IgG) and perform SARS-CoV-2 IgG antibody testing among asymptomatic health care workers (HCW) at the University Hospital Center Zagreb.
Three IgG serological assays (Abbott SARS-CoV-2 IgG, Elecsys Anti-SARS-CoV-2, and MAGLUMI 2019-nCoV IgG) were initially evaluated by analyzing 42 samples from confirmed COVID-19-recovered patients and 48 negative individuals. A total of 1678 HCW (~30% of all hospital employees) were screened for SARS-CoV-2 IgG with the Abbott assay, run on Abbott Architect i2000SR. The samples exceeding the predefined cut-off (1.4 S/C) were reanalyzed with the Elecsys, MAGLUMI, and VIDAS SARS-COV-2 IgG assays.
Initially, the MAGLUMI 2019-nCoV IgG produced 26.2% false negatives and the Elecsys Anti-SARS-CoV-2 produced one false positive. Among 1678 HCW, the Abbott assay showed only 10 (0.6%) positive results, with mostly mildly elevated signals. Nine of these samples were non-reactive when they were retested with the Elecsys, MAGLUMI, and VIDAS assays. As for the one remaining sample, it was positive when tested with the Elecsys assay, while the other two assays yielded negative results.
SARS-CoV-2 IgG seroprevalence among asymptomatic HCW in our hospital setting was low, with different assays indicating a different number of positive samples. One of the assays yielded a large false negative rate. These findings can be attributed to differences in assay formulation but also to heterogeneity and diverse reactivity of antibodies against SARS-CoV-2 antigens.
评估三种全自动血清学检测方法对 SARS-CoV-2 免疫球蛋白 G（IgG）的反应性，并对萨格勒布大学医院中心无症状的卫生保健工作者（HCW）进行 SARS-CoV-2 IgG 抗体检测。
通过分析 42 例确诊 COVID-19 康复患者和 48 例阴性个体的样本，对三种 IgG 血清学检测方法（雅培 SARS-CoV-2 IgG、Elecsys Anti-SARS-CoV-2 和 MAGLUMI 2019-nCoV IgG）进行了初步评估。Abbott Architect i2000SR 上运行 Abbott 检测，对 1678 名 HCW（约占所有医院员工的 30%）进行 SARS-CoV-2 IgG 筛查。超过预定义截止值（1.4 S/C）的样本用 Elecsys、MAGLUMI 和 VIDAS SARS-COV-2 IgG 检测方法进行重新分析。
最初，MAGLUMI 2019-nCoV IgG 产生了 26.2%的假阴性结果，Elecsys Anti-SARS-CoV-2 产生了一个假阳性结果。在 1678 名 HCW 中，Abbott 检测仅显示 10 例（0.6%）阳性结果，信号大多轻度升高。其中 9 例用 Elecsys、MAGLUMI 和 VIDAS 检测方法重新检测时无反应。对于剩余的一个样本，用 Elecsys 检测呈阳性，而其他两种检测方法则呈阴性。
我们医院环境中无症状 HCW 的 SARS-CoV-2 IgG 血清流行率较低，不同的检测方法表明阳性样本数量不同。其中一种检测方法的假阴性率很高。这些发现可归因于检测方法的配方差异，也归因于针对 SARS-CoV-2 抗原的抗体的异质性和不同反应性。
