Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada.
Department of Clinical Biochemistry, Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada.
Clin Biochem. 2021 Apr;90:1-7. doi: 10.1016/j.clinbiochem.2021.01.003. Epub 2021 Jan 19.
Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is diagnosed by molecular-based detection of SARS-CoV-2 RNA. Serologic testing detects antibodies specific to SARS-CoV-2 and IgM specifically may serve as an adjunct test to PCR early in disease. We evaluated the Abbott anti-SARS-CoV-2 IgM and IgG assays along with DiaSorin anti-SARS-CoV-2 IgG and Roche anti-SARS-CoV-2 Total.
Specimens from 175 PCR-positive patients and 107 control specimens were analyzed using Abbott IgM and IgG, DiaSorin IgG, and Roche Total (IgA, IgG, IgM) assays. Sensitivity, specificity, cross-reactivity, concordance between assays, trends over time, positive predictive value (PPV), and negative predictive value (NPV) were determined.
Abbott IgM sensitivity was 63.6% at 0 days post-PCR positivity, 76.5% at 1-5d, 76.3% at 6-14d, 85.2% at 15-30d, and 63.6% at > 30d. All assays exhibited highest sensitivity 15-30d post-PCR positivity (83.3-85.2%). Combining Abbott IgM and IgG improved sensitivity by 22.7% compared to IgG alone when tested 0d post-PCR positivity. All assays had a specificity of 100% and only Abbott IgG exhibited cross-reactivity (anti-dsDNA). Cohen's kappa varied between 0.86 and 0.93. Time to seroconversion from PCR positivity was lowest for Abbott IgM and highest for Abbott IgG. NPV was highest for Abbott IgM < 14 days post-PCR positivity and Abbott IgG ≥ 14 days.
The Abbott IgM assay exhibited the earliest response and greatest signal in most patients evaluated for serial sampling and had the highest NPV < 14 days post-PCR positivity, suggesting its potential utility as an adjunct test to PCR early in disease course.
由严重急性呼吸系统综合症冠状病毒 2（SARS-CoV-2）引起的 2019 年冠状病毒病（COVID-19）通过基于分子的 SARS-CoV-2 RNA 检测进行诊断。血清学检测检测到针对 SARS-CoV-2 的特异性抗体，IgM 可能在疾病早期作为 PCR 的辅助检测。我们评估了 Abbott 抗 SARS-CoV-2 IgM 和 IgG 检测以及 DiaSorin 抗 SARS-CoV-2 IgG 和 Roche 抗 SARS-CoV-2 总检测。
使用 Abbott IgM 和 IgG、DiaSorin IgG 和 Roche 总（IgA、IgG、IgM）检测分析了 175 例 PCR 阳性患者和 107 例对照标本。确定了灵敏度、特异性、交叉反应性、检测之间的一致性、随时间的趋势、阳性预测值（PPV）和阴性预测值（NPV）。
Abbott IgM 的灵敏度在 PCR 阳性后 0 天为 63.6%，1-5 天为 76.5%，6-14 天为 76.3%，15-30 天为 85.2%，>30 天为 63.6%。所有检测在 PCR 阳性后 15-30 天（83.3-85.2%）显示出最高的灵敏度。与单独使用 IgG 相比，当在 PCR 阳性后 0 天检测时，结合使用 Abbott IgM 和 IgG 可提高 22.7%的灵敏度。所有检测的特异性均为 100%，只有 Abbott IgG 表现出交叉反应性（抗 dsDNA）。Cohen's kappa 介于 0.86 和 0.93 之间。从 PCR 阳性到血清学转化的时间最短的是 Abbott IgM，最长的是 Abbott IgG。NPV 在 Abbott IgM<14 天和 Abbott IgG≥14 天的 PCR 阳性后最高。
Abbott IgM 检测在评估连续采样的大多数患者中表现出最早的反应和最大的信号，并且在 PCR 阳性后<14 天的 NPV 最高，这表明其作为疾病早期 PCR 的辅助检测具有潜在的应用价值。
