Background: The usability of laboratory tests related to SARS-CoV-2 is critically important for the world undergoing the COVID-19 pandemic. The present study aimed to assess diagnostic usability of rapid tests for detection of antibody against SARS-CoV-2 through comparison of their results with results of RT-PCR test for detection of SARS-CoV-2 genomic RNA and with results of a quantitative test for antibody detection.

Methods: Serum samples were collected from eighteen patients undergoing RT-PCR testing for SARS-CoV-2. Twelve patients were RT-PCR positive while six were negative. A quantitative test based on chemiluminescent immunoassay and three rapid tests based on immunochromatography were performed to detect anti-SARS-CoV-2 IgG and IgM.

Results: All the antibody tests exhibited poor sensitivity at the timing of initial RT-PCR diagnosis. IgG responses occurring prior to or simultaneously with IgM responses were observed through not only the quantitative test but also the three rapid tests. Based on concordance with the quantitative test results, the large variance among the three rapid tests was revealed.

Conclusions: All antibody tests were unsatisfactory to replace RT-PCR for early diagnosis of COVID-19. Rapid antibody tests as well as a quantitative antibody test were useful in assessment of immune responses in COVID-19. The obvious variance among the three rapid tests suggested limited accuracy and difficult standardization. Diagnostic usability of rapid antibody tests for COVID-19 should be investigated rigorously.

背景：与SARS-CoV-2相关的实验室测试的可用性对于经历COVID-19大流行的世界至关重要。本研究旨在通过将其结果与用于检测SARS-CoV-2基因组RNA的RT-PCR检测结果以及定量检测结果进行比较，来评估快速检测SARS-CoV-2抗体的诊断可用性用于抗体检测。

方法：收集十八名接受RT-PCR检测SARS-CoV-2的患者的血清样本。12例患者RT-PCR阳性，而6例阴性。进行了基于化学发光免疫分析的定量测试和基于免疫色谱的三个快速测试，以检测抗SARS-CoV-2 IgG和IgM。

结果：在初次RT-PCR诊断时，所有抗体测试均显示出较差的敏感性。不仅通过定量测试，而且通过三个快速测试，都观察到了在IgM应答之前或同时发生的IgG应答。根据定量测试结果，发现了三个快速测试之间的较大差异。

结论：所有抗体测试不能代替RT-PCR早期诊断COVID-19。快速抗体测试和定量抗体测试可用于评估COVID-19中的免疫应答。三种快速测试之间的明显差异表明准确性有限且难以标准化。应严格研究快速抗体检测COVID-19的诊断可用性。