Department of Pathology and Laboratory Medicine, Beaumont Health, Royal Oak, MI, USA; Department of Pathology and Laboratory Medicine, Oakland University William Beaumont School of Medicine, Auburn Hills, MI, USA.
Department of Pathology and Laboratory Medicine, Beaumont Health, Royal Oak, MI, USA.
J Clin Virol. 2020 Dec;133:104663. doi: 10.1016/j.jcv.2020.104663. Epub 2020 Oct 27.
Antibody testing has recently emerged as an option to assist with determining exposure to SARS-CoV-2, the causative agent of COVID-19. Elucidation of the kinetics and duration of the humoral response is important for clinical management and interpreting results from serological surveys.
Here we evaluated the clinical performance of Abbott SARS-CoV-2 IgM and IgG assays, as well as the longitudinal dynamics of the antibody response in symptomatic COVID-19 patients.
The diagnostic specificity was 100 % for IgM and 99.67 % for IgG using 300 pre-COVID-19 serum specimens. Using 1349 sequential serum samples collected up to 168 days post symptom onset from 427 PCR-confirmed individuals, clinical test sensitivity of the SARS-CoV-2 IgM assay was 24.6 % at ≤7 days, 75.3 % at 8-14 days, 95.0 % at 15-21 days, and 96.0 % at 4-5 weeks (peak test sensitivity). The median duration of time for IgM seroconversion was 10 days. IgM levels declined steadily 4-5 weeks after symptom onset, and the positive rate dropped to 30.8 % at >3 months. The diagnostic sensitivity for the SARS-CoV-2 IgG assay post symptom onset was 23.2 % at ≤7 days, 69.5 % at 8-14 days, 93.6 % at 15-21 days, and 99.6 % at 4-5 weeks (peak test sensitivity). The median duration of time for IgG seroconversion was 11.5 days. During the convalescent phase of the infection, a decline in the IgG level was observed in patients who were followed for >100 days. Despite that decline, 92.3 % of the patient cohort remained IgG positive 3-6 months following symptom onset.
This study demonstrates the Abbott IgM assay against SARS-CoV-2 is detected slightly earlier compared to IgG, with both tests exhibiting excellent overall sensitivity and specificity. In symptomatic patients who test negative by PCR for a SARS-CoV-2 infection, assessing IgM and IgG antibodies can aid in supporting a diagnosis of COVID-19.
抗体检测最近已成为一种辅助确定 SARS-CoV-2（COVID-19 的致病因子）暴露的方法。阐明体液反应的动力学和持续时间对于临床管理和解释血清学调查结果很重要。
本研究评估了 Abbott SARS-CoV-2 IgM 和 IgG 检测的临床性能，以及症状性 COVID-19 患者的抗体反应的纵向动态。
使用 300 份 COVID-19 前血清标本，IgM 的诊断特异性为 100%，IgG 的诊断特异性为 99.67%。使用从 427 名经 PCR 确诊的个体中采集的 1349 份症状出现后长达 168 天的连续血清样本，SARS-CoV-2 IgM 检测的临床检测敏感性在≤7 天时为 24.6%，在 8-14 天时为 75.3%，在 15-21 天时为 95.0%，在 4-5 周（峰值检测敏感性）时为 96.0%。IgM 血清转换的中位时间为 10 天。IgM 水平在症状出现后 4-5 周内稳步下降，3 个月后阳性率降至 30.8%。症状出现后 SARS-CoV-2 IgG 检测的诊断敏感性在≤7 天时为 23.2%，在 8-14 天时为 69.5%，在 15-21 天时为 93.6%，在 4-5 周（峰值检测敏感性）时为 99.6%。IgG 血清转换的中位时间为 11.5 天。在感染的恢复期，观察到随访时间超过 100 天的患者 IgG 水平下降。尽管如此，92.3%的患者队列在症状出现后 3-6 个月仍保持 IgG 阳性。
本研究表明，与 IgG 相比，Abbott 针对 SARS-CoV-2 的 IgM 检测略早，两种检测均具有出色的总体敏感性和特异性。在 PCR 检测 SARS-CoV-2 感染呈阴性的症状性患者中，评估 IgM 和 IgG 抗体有助于支持 COVID-19 的诊断。
