血清热灭活对胶体金法检测新型冠状病毒抗体的影响

Effect of serum heat inactivation on the detection of 2019-nCoV antibodies

目的评估热灭活对胶体金法检测新型冠状病毒(2019 novel coronavirus,2019-nCoV)特异性IgM和IgG抗体的影响。方法收集新型冠状病毒肺炎(Coronavirus Disease 2019,COVID-19)确诊住院患者血清106份及健康医护人员血清标本52份,采用商品化2019-nCoV抗体检测试剂盒(胶体金法)分别对56℃30 min热灭活前后的血清标本特异性IgM和IgG抗体进行检测,分析灭活前后抗体检出率的差异及一致性。根据患者发病时间分析热灭活对不同发病阶段抗体检出率的影响。结果健康对照组标本灭活前后测试均为阴性。56℃30 min灭活后降低2019-nCoV特异性IgM和IgG抗体的检出率,106例确诊患者IgM抗体总检出率由66.04%(70/106)降至43.40%(46/106),差异有统计学意义(χ^(2)=22.042,P=0.000);IgG抗体阳性率由81.13%(86/106)降至76.42%(81/106),差异无统计学意义(χ^(2)=0.800,P=0.063)。在发病第3周、第5周和第6周热灭活可显著降低IgM抗体检出率。不同发病时段,血清热灭活前后IgG抗体检出率差异无统计学意义。结论56℃30 min热灭活降低胶体金法2019-nCoV特异性IgM抗体检出率,易导致假阴性结果。

Objective To assess the effect of serum heat inactivation on the detection of 2019 novel coronavirus(2019-nCoV)specific IgM and IgG antibodies by colloidal gold method.Methods The serum specimens were collected from a total of 106 Coronavirus Disease 2019(COVID-19)patients and 52 control subjects.Both the fresh serum and the heat inactivated serum samples from the same patient were detected simultaneously with the 2019-nCoV IgM and IgG antibodies detection kit(colloidal gold method).According to the patient′s onset time,the positive rates of antibodies production profile were calculated.The influence of heat inactivation on the detection rates of antibodies at different stages of disease after onset was analyzed.Results The test results of the specimens of the healthy control group before and after inactivation were all negative.For the 106 specimens of COVID-19 patients,the detection rates of 2019-nCoV specific IgM and IgG antibodies were reduced after heating at 56℃for 30 min.The positive rates of IgM antibodies significantly decreased from 66.04%(70/106)to 43.40%(46/106)(χ^(2)=22.042,P=0.000),while the positive rates of IgG antibodies slightly decreased from 81.13%(86/106)to 76.42%(81/106)(χ^(2)=0.800,P=0.063).Further analysis revealed that there was a significant difference in the positive rates of IgM antibodies before and after heat inactivation in the 3rd,5th and 6th week after onset.However,there was no statistically significant difference in the detection rates of IgG antibodies before and after serum heat inactivation in different periods of onset.Conclusions Heat inactivation significantly decreased the detection rates of 2019-nCoV specific IgM antibodies,which may lead to serological false negative results.