核酸污染及其引起呼吸道病毒核酸检测假阳性的鉴定与防范

Identification and Prevention of Nucleic Acid Contamination and the Resultant False Positive Nucleic Acid Tests for Respiratory Viruses

摘要: 呼吸道病毒引起的感染性疾病是一类严重威胁人类健康和生命的重大疾病。利用口咽拭子或鼻咽拭子进行呼吸道病原体鉴定，对于病毒性呼吸道感染疾病的临床诊疗和疾病防控均具有重要意义。基于PCR的病毒核酸检测具有操作简便、灵敏度高、特异性强等优点，现已普遍作为病毒病原体鉴定的常用手段。然而由于PCR超高的灵敏度，病毒核酸检测容易因试剂、耗材和环境受到病毒核酸污染而出现假阳性结果，从而影响病原体鉴定的准确性。从事呼吸道病毒研究或检测的科研、医疗工作者由于频繁使用、接触含有病毒核酸序列的表达质粒或阳性对照质粒，其口咽和鼻咽面临核酸污染的高风险，进而在取样口咽拭子或鼻咽拭子进行呼吸道病毒核酸检测时容易出现假阳性。本文以新型冠状病毒为例，分析了核酸污染引起核酸检测假阳性的可能发生情况，并探讨了核酸污染引起核酸检测假阳性的鉴定方法以及预防、消除核酸污染的处理方法，以期减少该类事件的发生，并助力病毒性呼吸道感染的精准诊疗。

Abstract: Infectious diseases caused by respiratory viruses impose a severe threat to human health and life. Identification of the respiratory pathogen using oropharyngeal or nasopharyngeal swabs is essential for clinical diagnosis and treatment of viral respiratory infections, as well as disease control and prevention. PCR-based viral nucleic acid tests have been widely used in identification of viral pathogen due to its advantages in simple operation, high sensitivity and specificity. However, the super-sensitivity of PCR also renders viral nucleic acid tests high incidence of false positive results once the reagents, materials and environments get contaminated with viral nucleic acids, which interferes with the accuracy of pathogen identification. As research and hospital personnel engaged in research or detection of respiratory viruses frequently use or contact with expression plasmids or positive control plasmids that contain viral nucleic acid sequence, their oropharynx and nasopharynx face high risk of nucleic acid contamination, leading to high incidence of false positive results during nucleic acid tests of respiratory viruses using their oropharyngeal or nasopharyngeal swabs. Taking advantage of SARS-CoV-2 as an example, here we analyzed the potential situations that nucleic acid contamination-caused false positive results occur, and discussed how to identify nucleic acid contamination as the cause of false positive results, how to prevent and handle with nucleic acid contamination. We hope this study would be helpful to reduce the incidence of this event and aid precision diagnosis and treatment of viral respiratory infections.