新型冠状病毒监测网络省市级疾控实验室核酸检测室间质评

  目的  对全国32个省市级疾控机构新冠监测网络实验室新型冠状病毒（新冠病毒）变异株核酸检测能力进行室间质评，同时对常规所用新冠病毒核酸检测试剂性能进行评价。  方法  制备新冠病毒武汉株及4个关切变异株、人冠状病毒OC43（HCoV-OC43）和H3亚型流感病毒（H3N2）核酸样本，发放给全国31个省、自治区及直辖市和新疆生产建设兵团疾病预防控制中心新冠监测网络实验室进行室间质评。 每个实验室的考核样本盘包括两种不同Ct值（～35、～30）的新冠病毒武汉株、关切变异株（α和γ或β和δ）、HCoV-OC43、流感病毒核酸样本共10支。 根据反馈结果计算检测符合率并对检测结果进行深入分析。 同时，收集各考核实验室常用的新冠病毒核酸检测试剂盒进行检测性能验证。  结果  全国省市级疾控机构新冠监测网络实验室室间质评总体达标率为100%（32/32），总体优秀率72%（23/32）；初测中，新冠病毒、HCoV-OC43核酸样本检测总符合率为99.7%（319/320）、89%（57/64）。 对32个考核实验室送检的新冠病毒核酸检测试剂盒进行性能验证，66%（33/50）的试剂盒检测限与说明书相符，92%（11/12）的受检试剂盒特异性达标。  结论  32个省市疾控机构实验室新冠病毒核酸检测能力全部达标，均能检测新冠病毒武汉株及阿尔法、贝塔、伽马和德尔塔变异株；送检的部分核酸检测试剂检测限与说明书不符，检测性能有待改进。

External quality assessment of nucleic acid testing in provincial or municipal CDC laboratories in the COVID-19 surveillance network in China

  Objective  To understand the RNA detection performance of SARS-CoV-2 Variants of Concern (VOCs) in 32 provincial or municipal CDC laboratories in COVID-19 surveillance network in China through an external quality assessment (EQA), and evaluate the clinical performance of the current SARS-CoV-2 nucleic acids detection kits used and provided by the participating laboratories.   Methods  The viral RNA extractions of SARS-CoV-2 Wuhan strain, four VOCs (Alpha, Beta, Gamma, and Delta), human coronavirus OC43 (HCoV-OC43), and influenza A virus (H3N2) was conducted. The viral RNA was used to prepare EQA panel samples with high (～35) and low (～30) Ct values. The EQA panel included 10 RNA samples (two Ct sets) from three SARS-CoV-2 strains (Wuhan strain, Beta variant, and Delta variant or Wuhan strain, Alpha variant, and Gamma variant), HCoV-OC43 strain, and influenza virus strain. Each participating laboratory was given a random panel of samples for assessment. According to the feedback results, the detection coincidence rate was calculated, and the results were analyzed comprehensively. Furthermore, SARS-CoV-2 nucleic acid detection kits used by the participating laboratories were collected to verify the detection limit and specificity.   Results  In the EQA, all the participating laboratories met the assessment standard and there were 72% (23/32) laboratories with excellent performance. The overall coincidence rate was 99.7% (319/320) in SARS-CoV-2 RNA detection and 89% (57/64) in HCoV-OC43 RNA detection in the EQA. Among the rRT-PCR-based SARS-CoV-2 nucleic acid detection kits provided by 32 participating laboratories, 66% (33/50) of the kits met limit of detection, and 92% (11/12) of the kits met the specificity standard.   Conclusion   All the participating laboratories were capable of detecting SARS-CoV-2 RNA, including prototype Wuhan strain and VOCs of Alpha, Beta, Gamma, and Delta. Some SARS-CoV-2 detection kits provided by participating laboratories didn’t meet the limit of detection, and the specificity needs improvement.