Preface 

　　The Standard Operating Procedures is written in order to standardize the procedures, maintain the quality and minimize the environmental contamination and instruct the operation of all the technicians in Chinese National Influenza Center.　　

　　According to Law on the Prevention and Control of Infectious Diseases of People's Republic of China, Unified Requirements of the People’s Republic of China on the Biosafety of National Standard Laboratories (GB 1989-2004) and relevant laws and regulations,  Laboratory Biosafety Manual of WHO (3nd Edition) and relevant recommendations of influenza/avian influenza, Diagnostic Criteria for Influenza, Diagnostic Criteria of Human Infection with Highly Pathogenic Avian Influenza Virus and Technical Plan of Avian Influenza Laboratory Detection, on the basis of the former Standard Operating Procedures of Chinese National Influenza Center (2004 Edition), many new content are updated and this new edition is revised.　　

　　The Standard Operating Procedures includes SOP of basic biological experiment, collection of specimens, virus isolation, virus identification, nucleic acid detection, of serological detection, animal test, drug resistance detection and other SOP for the management of specimens and strains. Based on the requirements and development of work in recent years, we establish a lot of new empirical methods such as molecular differential diagnostic (MDD) technique, nucleic acid sequence-based amplification (NASBA) detection for avian influenza H5N1, single radial hemolysis technique (SRH) and so on. Protocols in the research work are also included.　　

　　Comparing with the former edition, the structural arrangement of this SOP is more reasonable which is classified according to the different aims of the experiment and more convenient for reading. Furthermore, the content is enriched and easier to understand and operate. Thirdly, it is described in a more clear way after careful consideration and actively discussion.　　

　　The Standard Operating Procedures is created by the contribution of all staff of Chinese National Influenza Center. While every effort is to make this manual correct, but mistakes might be present. Because of the different understanding of different contributors, some operating procedures might be of one-side or inaccurate. If any mistake is found, please tell us so that we can update the change and revise in our practice to satisfy the demand of future work. If there are any unclear steps, please refer to Chinese edition of this manual.

　　The Standard Operating Procedures is effective after it has been authorized.