Evaluation of Commercial Diagnostic Assays for the Specific Detection of Avian Influenza A (H7N9) Virus RNA Using a Quality-Control Panel and Clinical Specimens in China

A novel avian influenza A H7N9-subtype virus emerged in China in 2013 and threatened global public health. Commercial kits that specifically detect avian influenza A (H7N9) virus RNA are urgently required to prepare for the emergence and potential pandemic of this novel influenza virus. The safety and effectiveness of three commercial molecular diagnostic assays were evaluated using a quality-control panel and clinical specimens collected from over 90 patients with confirmed avian influenza A (H7N9) virus infections. The analytical performance evaluation showed that diverse influenza H7N9 viruses can be detected with high within- and between-lot reproducibility and without cross-reactivity to other influenza viruses (H1N1 pdm09, seasonal H1N1, H3N2, H5N1 and influenza B). The detection limit of all the commercial assays was 2.83 Log10 copies/μl [0.7 Log10TCID50/mL of avian influenza A (H7N9) virus strain A/Zhejiang/DTID-ZJU01/2013], which is comparable to the method recommended by the World Health Organization (WHO). In addition, using a WHO-Chinese National Influenza Center (CNIC) method as a reference for clinical evaluation, positive agreement of more than 98% was determined for all of the commercial kits, while negative agreement of more than 99% was observed. In conclusion, our findings provide comprehensive evidence for the high performance of three commercial diagnostic assays and suggest the application of these assays as rapid and effective diagnostic tools for avian influenza A (H7N9) virus in the routine clinical practice of medical laboratories.

2013年，一种新型甲型H7N9亚型禽流感病毒（avian influenza A H7N9-subtype virus）在中国首次出现，对全球公共卫生构成严重威胁。为应对该新型流感病毒的出现及潜在大流行风险，亟需可特异性检测该病毒RNA的商用检测试剂盒。本研究采用质控品组及90余例经确诊的甲型H7N9亚型禽流感病毒感染者的临床标本，对3款商用分子诊断试剂盒的安全性与有效性进行了评估。分析性能评估结果显示，该类试剂盒可检出多种甲型H7N9流感病毒，批内与批间重复性优异，且不会与其他流感病毒（甲型H1N1 pdm09、季节性甲型H1N1、H3N2、H5N1及乙型流感病毒）发生交叉反应。所有受试商用试剂盒的检测限均为2.83 Log10 拷贝/微升[对应甲型H7N9亚型禽流感病毒毒株A/Zhejiang/DTID-ZJU01/2013的0.7 Log10TCID50/mL]，该性能与世界卫生组织（World Health Organization, WHO）推荐的检测方法相当。此外，以世界卫生组织-中国国家流感中心（Chinese National Influenza Center, CNIC）的检测方法作为临床评估参照标准，所有商用试剂盒的阳性符合率均超过98%，阴性符合率则高于99%。综上，本研究结果为3款商用诊断试剂盒的优异性能提供了全面佐证，表明此类试剂盒可作为甲型H7N9亚型禽流感病毒的快速有效检测工具，应用于医学实验室的常规临床检测工作中。