Xue Xiongyan, Zhu Changlin, Huang Shaozhen, Pan Lianhua, Xu Jianhua, Li Weixuan
Clinical Laboratory, Foshan First People's Hospital, Foshan 528000, China.
Medical Laboratory Center, Shunde Hospital of Guangzhou University of Chinese Medicine, Foshan 528333, China.
Nan Fang Yi Ke Da Xue Xue Bao. 2020 Mar 30;40(3):316-320. doi: 10.12122/j.issn.1673-4254.2020.03.03.
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.
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.
With immuno-chromatography, 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%: 0.9998-1.000, < 0.001) between the results before and after sample inactivation.
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.
评估56℃加热灭活血液样本30分钟对采用不同方法检测新型冠状病毒2（SARS-CoV-2）抗体结果的影响。
本回顾性研究纳入了我院11例确诊为新型冠状病毒肺炎（COVID-19）的患者和10例非COVID-19疾病患者。于2020年2月12日至18日期间采集每位患者的血清、血浆和全血样本，并采用双盲设计，对样本在56℃加热灭活30分钟前后进行SARS-CoV-2抗体检测。在所有样本中，采用免疫层析法检测SARS-CoV-2总抗体，采用荧光免疫层析法检测IgM抗体；采用化学发光免疫分析法检测血清和血浆样本中的IgM和IgG抗体。我们比较了检测结果，并分析了样本加热灭活前后IgM和IgG抗体半定量检测结果的相关性。
采用免疫层析法时，COVID-19病例血清和血浆样本加热灭活前后SARS-CoV-2总抗体检测的符合率为90.0%，阴性病例为100.0%，总符合率为95.2%；全血样本中，SARS-CoV-2总抗体的总符合率为100.0%。采用荧光免疫层析法检测血清、血浆和全血样本中的IgM抗体时，SARS-CoV-2阳性和阴性病例的符合率以及灭活前后的总符合率分别为100.0%、0和47.6%。采用化学发光免疫分析法检测血清IgM和IgG抗体以及血浆IgG抗体时，SARS-CoV-2阳性和阴性病例的符合率以及灭活前后的总符合率均为100.0%，血浆IgM抗体的总符合率为95.2%。对血清和血浆样本中IgM和IgG检测的半定量结果进行Pearson相关性分析显示，样本灭活前后结果的相关系数为0.9999（95%：0.9998 - 1.000，P < 0.001）。
56℃加热灭活血液样本30分钟对检测SARS-CoV-2抗体的免疫层析法和化学发光免疫分析法结果无明显影响，但可降低操作人员的感染风险。加热灭活的样本不能用于SARS-CoV-2抗体的荧光免疫层析检测。
