血液样本灭活处理对三种SARS-CoV-2抗体检测方法结果的影响

目的 探讨56 ℃ 30 min灭活处理对不同方法测定2019新型冠状病毒（SARS-CoV-2）抗体检测结果的影响。方法 本文为回顾性研究。收集2020年2月12~18日在佛山市第一人民医院确诊为新型冠状病毒性肺炎患者血清样本、血浆样本及全血样本各11份，同时收集同期疑似病例及其他疾病患者血清、血浆及全血样本各10份，采用双盲法，在样本采用56 ℃ 30 min灭活处理前后，分别采用免疫层析法检测样本中的SARS-CoV-2总抗体、采用荧光免疫层析法检测样本中的SARS-CoV-2 IgM抗体、采用化学发光荧光免疫分析法检测血清及血浆样本SARS-CoV-2 IgM及SARS-CoV-2 IgG，比较灭活前与灭活处理后样本的抗体检测结果，并采用Pearson相关性分析灭活前后检测IgM及IgG半定量检测结果的相关性。结果 免疫层析法检测灭活前后血清与血浆样本中SARS-CoV-2总抗体的阳性样本符合率为90.9%，阴性符合率为100.0%，总符合率均为95.2%。免疫层析法检测灭活前后全血样本中SARS-CoV-2总抗体的总符合率为100.0%。荧光免疫层析法检测灭活前后血清、血浆及全血样本中SARS-CoV-2 IgM抗体的阳性符合率均为100.0%，阴性符合率均为0%，总符合率均为47.6%。化学发光免疫分析法检测灭活 前后血清样本中SARS-CoV-2 IgM及IgG抗体及血浆中的IgG抗体，阳性符合率、阴性符合率及总符合率均为100.0%，检测血浆IgM抗体的总符合率为95.2%。采用Pearson相关对灭活前后血清及血浆样本IgM和IgG半定量检测结果进行相关性分析，其中IgM灭活前后结果的相关系数为0.9999（95%CI：0.9998~1.000，P<0.001），IgG灭活前后结果的相关系数为0.9999（95%CI： 0.9998~1.000，P<0.001）。结论 56 ℃ 30 min灭活处理血液样本对免疫层析法及化学发光免疫分析法检测SARS-CoV-2抗体结果几乎无影响，可在检测前先进行灭活以降低检验人员感染风险，荧光免疫层析法不可使用灭活后样本进行检测。

Effect of heat inactivation of blood samples on the efficacy of three detection methods of SARS-CoV-2 antibodies

Objective To evaluate the effects of heat inactivation of blood samples at 56 ℃ for 30 min on the results of SARS-CoV-2 antibody detection using different methods. Methods This retrospective study was conducted in 11 patients with established diagnosis of COVID-19 and 10 patients with diseases other than COVID-19 in our hospital. We collected samples of serum, plasma and whole blood from each patient between February, 12 and 18, 2020, and with a double-blind design, the samples were examined for SARS-CoV-2 antibodies before and after heat inactivation at 56 ℃ for 30 min. In all the samples, the total SARS-CoV-2 antibodies were detected using immunochromatography, and the IgM antibodies were detected using fluorescence immunochromatography; the IgM and IgG antibodies in the serum and plasma samples detected with chemiluminescence immunoassay. We compared the detection results and analyzed the correlation of semi-quantitative detection results of IgM and IgG antibodies before and after heat inactivation of the samples. Results With immunochromatography, the coincidence rate of the total SARS-CoV-2 antibody detection before and after heat inactivation of the serum and plasma samples was 90.0% in COVID-19 cases and 100.0% in the negative cases, resulting in a total coincidence rate 95.2%; for the whole blood samples, the total coincidence rates of the total SARS-CoV-2 antibodies were 100.0%. For detection of IgM antibodies in the serum, plasma and whole blood samples using fluorescence immunochromatography, the coincidence rates in SARS-CoV-2-positive and negative cases and the total coincidence rate before and after inactivation were 100.0%, 0 and 47.6% , respectively. For detection of serum IgM and IgG antibodies and plasma IgG antibodies with chemiluminescence immunoassay, the coincidence rates in SARS-CoV-2-positive and negative cases and the total coincidence rate before and after inactivation were all 100.0%, and the total coincidence rate of plasma IgM antibodies was 95.2%. Pearson correlation analysis of the semi-quantitative results of IgM and IgG detection in the serum and plasma samples showed a correlation coefficient of 0.9999 (95%CI: 0.9998-1.000, P<0.001) between the results before and after sample inactivation. Conclusion Heat inactivation of blood samples at 56 ℃ for 30 min does not obviously affect the results of immunochromatography and chemiluminescent immunoassay for detection of SARS-COV-2 antibodies but can reduce the risk of infection for the operators. Heat-inactivated samples can not be used in fluorescence immunochromatography for SARS-CoV-2 antibody detection.