流感检测

流行性感冒是一种季节性呼吸系统病毒感染，从十一月末延续至春季早期。流行性感冒是一种常见的呼吸系统疾病，每年大概有3000至5000万美国人感染此病，带来头痛、发热、寒战、肌肉疼痛、无力、鼻塞、喉咙肿痛以及咳嗽等症状。流感症状可比常见的感冒更严重，持续时间更长。流感及其并发症可导致美国每年超过1000,000人住院，20,000人死亡。特别是儿童、老年人及免疫系统受损或肺癌患者。

        流感有甲型流感和乙型流感两种类型，两种病毒均可变异产生新的变种。通常流感病毒A单一毒株在特定的流感季节占统治地位，虽然有时可能是甲型流感和乙型流感同一时间在社区爆发。

        流感检测依靠检测感染者呼吸道分泌物中的病毒。病毒通常在疾病发作最初几天可检测到，所以大多数实验必须在发作初期进行。抗病毒药物已用于甲型流感、乙型流感或两者混合感染的治疗。如果在发病48小时以内进行治疗，可减轻症状，减少患病时间。（如果治疗在48小时后进行，则对其他病毒或细菌感染疗效不佳。）

        流感检测可用于流感的诊断和指导治疗，同时在寻找其他疾病时可排除流感。快速流感抗原检测鼻腔分泌物中是否有病毒存在，是最常见的一种方法。基于这种方法，可在医生办公室30分钟之内完成，或者送至实验室。基于检测所使用的特定类型，可以确定是否存在流感病毒，或区分病毒类型（A型或B型）。快速流感检测最大的不足在于会漏检约30%的病例，偶尔会出现假阳性结果。

        其他的流感检测更为敏感和特异。鼻腔分泌物可送至实验室通过荧光抗体染色检测。样本采集数小时后可区分流感病毒A与流感病毒B，同时可以启动合适的抗病毒治疗。这种方法需要特殊显微镜和熟练的实验室工作人员阅读解释结果。这通常不在医生办公室进行。

        有时医生会申请病毒培养。在这个检测中，流感病毒在实验室生长并被鉴定。明确病毒株型（A型，B型或其他呼吸道病毒）是有利的。快速培养方法，又称为壳病毒培养，只需培育24小时即可观察结果，而传统的病毒培养方法在可检测出病毒前需要数天时间。培养基中生长的病毒可判断流感病毒株是否在社区流行。明确流感是否爆发有助于医疗中心工作人员在社区中进行流感预防和治疗。

样本采集技术在流感检测中十分重要。最佳样本为鼻腔抽吸液，但是最常用的样本为鼻咽拭子或者鼻腔灌洗液。样本采集者用注射器将少量生理盐水注入患者鼻腔，然后轻轻抽吸或者根据重力原理收集混合液体（生理盐水和粘液）。为保存样本中病毒，样本转送至实验室途中需放在特殊容器中，即“病毒转运液”或VTM。

        鼻咽拭子采集即将拭子轻轻探入一只鼻孔至遇到阻力（大约2英寸）时停止，旋转数周后取出拭子。整个过程并不痛苦，但会产生痒感而导致流泪。医生通常采集成人鼻咽拭子，而采集儿童鼻腔灌洗液或抽吸液样本。在某些情况下，医生会采用喉拭子，喉拭子采集样本携带病毒少于鼻咽抽吸液，可能不太适合快速检测。

新闻要事: Don't rely solely on rapid tests for H1N1, CDC warns (2009)

NIAID: What’s the Difference Between Seasonal Flu, Pandemic Flu, and Avian (Bird) Flu?
Centers for Disease Control and Prevention (CDC): Influenza
CDC: Avian Influenza (Bird Flu)
NIH, MEDLINEplus Health Information: Influenza
American Lung Association: A Survival Guide for Preventing and Treating Influenza and the Common Cold
World Health Organization: Influenza

S1
Thomas, Clayton L., Editor (1997). Taber’s Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].

S2
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby’s Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.

S3
Ault, A. (2002 October 7). CDC Urges Flu, Pneumococcal Shots for Seniors [1 paragraph]. MEDLINEplus & Reuters Health Information [On-line information]. Available FTP: http://www.nlm.nih.gov/medlineplus/news/fullstory_9746.html

S4
NIAID (2001 July). Flu [35 paragraphs]. Fact Sheet, National Institute of Allergy and Infectious Diseases, National Institutes of Health [On-line information]. Available FTP: http://www.niaid.nih.gov/factsheets/flu.htm

S5
CDC (2002 September 20, Updated). Flu Facts for Everyone [24 paragraphs]. Centers For Disease Control (CDC) [On-line information]. Available FTP: http://www.cdc.gov/nip/Flu/Public.htm

S6
CDC (2002 July 9, Reviewed). Influenza: The Disease [11 paragraphs]. National Center for Infectious Diseases [On-line information]. Available FTP: http://www.cdc.gov/ncidod/diseases/flu/fluinfo.htm

S7
CDC (2002 July 9, Reviewed). Antiviral Drug Information [10 paragraphs]. National Center for Infectious Diseases [On-line information]. Available FTP: http://www.cdc.gov/ncidod/diseases/flu/fluviral.htm

S8
CDC (2002). Laboratory Diagnostic Procedures for Influenza, Diagnosis of influenza [6 paragraphs]. National Center for Infectious Diseases [On-line information]. Available FTP: http://www.cdc.gov/ncidod/diseases/flu/flu_dx_table.htm

S9
CDC (2001 November 27, Modified). Inhalational Anthrax, Influenza, or Influenza-like Illness? [9 paragraphs]. Centers for Disease Control and Prevention [On-line information]. Available FTP: http://www.cdc.gov/nip/Flu/MMWR_summary_11-9.htm

S10
Hurtado, R. (2002 March 1). Influenza [11 paragraphs]. MEDLINEplus Health Information, Encylopedia [On-line information]. Available FTP: http://www.nlm.nih.gov/medlineplus/ency/article/000080.htm

S11
Montato, N., et. al. (2000 December 1). Updated Treatment for Influenza A and B [35 paragraphs]. American Family Physician [On-line information]. Available FTP: http://www.aafp.org/afp/20001201/2467.html

S12
Kingston, B. and Wright, C. (2002 January 1). Influenza in the Nursing Home [23 paragraphs]. American Family Physician [On-line journal]. Available FTP: http://www.aafp.org/afp/20020101/75.html

S13
Baylor College of Medicine (2002). Virology Question of the Month, How accurate are the new rapid tests for flu? [4 paragraphs]. Diagnostic Virology Laboratory Newsletter [On-line newsletter]. Available FTP: http://www.bcm.tmc.edu/pedi/infect/dvl/nws10_2001.htm

S14
Locke, J. (2001 July 9). Rapid Infectious Disease Testing (Strep and Flu Diagnostics) – The Promise and Pitfalls [16 paragraphs]. Clinical Laboratory Strategies [Unpublished version of published article]. Available E-mail: jtechwriter@yahoo.com

S15
Harvard (2002 October). Fleeing crummy? Is it the flu? [14 paragraphs]. Harvard Health Letter [Newsletter]. Associated FTP: http://www.health.harvard.edu

S16
College of American Pathology (2002 October 09). CLIA Waived Test List [56 paragraphs]. CAP Laboratory Improvement, Surveys/EXCEL (On-line serial). Available FTP: http://www.cap.org/html/lip/waived.html