Abstract: Objective To develop the efficacy of time resolved fluorescence immunoassay (TRFIA) for the detection of COVID-19 specific IgM antibodies. Methods A total of 36 COVID-19 patients in our hospital (From January 2020 to March 2020) and 36 common fever patients excluding COVID-19 in the same period were selected for TRFIA detection and GICA detection of specific IgM antibodies. The specific IgM antibody levels of COVID-19 patients and common fever patients were compared, and the results of TRFIA and GICA detection of COVID-19 specific IgM antibody were counted, and the diagnostic efficacy (sensitivity, specificity and accuracy) and the results of COVID-19 specific IgM antibody of different disease courses were calculated. Results The specific IgM antibody level of COVID-19 patients was higher than that of patients with normal fever (P<0.05). TRFIA detected 34 true positive and 34 true negative COVID-19 specific IgM antibodies. GICA detected 26 true positive and 33 true negative COVID-19 specific IgM antibodies. The sensitivity and accuracy of TRFIA in detecting COVID-19 specific IgM antibody were 94.44% and 94.44% respectively higher than those of GICA(72.22% and 81.94%) (P<0.05). The specificity of TRFIA and GICA was 94.44% and 91.67%, respectively, the difference was not statistically significant (P>0.05). The positive rate of specific IgM antibody increased first and then decreased with the prolongation of the onset time. Conclusion The specific IgM antibody level of COVID-19 patients is relatively high, and TRFIA detection can improve the diagnostic sensitivity and accuracy, and the positive results first increase and then decrease as the disease progresses, which is conducive to the early diagnosis and monitoring of the treatment process, with high clinical application value.

Key words: time-resolved fluorescence immunoassay, colloidal gold immunochromatography, COVID - 19, specific IgM antibody, diagnostic performance

摘要： 目的 时间分辨荧光免疫测定（TRFIA）检测新型冠状病毒肺炎（COVID-19）特异性IgM抗体的效果。方法 选取我院COVID-19患者36例（2020年1月~2020年3月）及同期排除COVID-19的普通发热患者36例,均行TRFIA检测及胶体金免疫层析（GICA）检测特异性IgM抗体,比较COVID-19患者、普通发热患者特异性IgM抗体水平,统计TRFIA检测、GICA检测COVID-19特异性IgM抗体的结果并计算诊断效能（灵敏度、特异度、准确度）,不同病程COVID-19特异性IgM抗体的结果。结果 COVID-19患者特异性IgM抗体水平高于普通发热患者（P<0.05）;TRFIA检测COVID-19特异性IgM抗体真阳性34例,真阴性34例;GICA检测COVID-19特异性IgM抗体真阳性26例,真阴性33例;TRFIA检测COVID-19特异性IgM抗体灵敏度94.44%、准确度94.44%高于GICA检测72.22%、81.94%（P<0.05）;TRFIA检测特异度为94.44%,GICA检测特异度为91.67%,差异无统计学意义（P>0.05）;且随着发病时间延长,特异性IgM抗体阳性率呈先升高再降低趋势。结论 COVID-19患者特异性IgM抗体水平较高,经TRFIA法检测能提高诊断灵敏度、准确度,且随着病情发展阳性率先升高再降低,有助于早期诊断、监测治疗进程,具有较高临床应用价值。

关键词: 时间分辨荧光免疫测定, 胶体金免疫层析, 新型冠状病毒肺炎, 特异性IgM抗体, 诊断效能