title: [The significance of different sample types in study of pandemic A (H1N1) influenza diagnosis].
abstract: OBJECTIVE
  To explore the value of different types of samples, including throat swabs, stools, bloods in pandemic A (H1N1) influenza diagnosis and virus shedding patterns.
  
  
  METHODS
  From May to June in 2009, 135 samples were collected from 23 confirmed cases of pandemic influenza A (H1N1) infection, including 99 throat swabs, 14 stools, 11 bloods, 1 respiratory tract washing from 13 confirmed cases and 10 blood samples from other confirmed cases. The virus was detected by real-time RT-PCR, the antibody was detected by haemagglutination inhibition assay.
  
  
  RESULTS
  For 99 throat swabs of 13 patients, the median time of the first positive real-time RT-PCR was 1 day (ranged from 0 to 7 days) after the onset of the symptoms of illness; the median length of time duration of positive real-time RT-PCR results from throat swabs was 3 days (ranged from 1 to 15 days). Four cases intermittently released virus. One respiratory tract washing sample was positive. In 14 stools, 8 stools were real-time RT-PCR positive, the positive rate was 57.14%. The median time of the positive real-time RT-PCR was 3 days (ranged from 1 to 4 days) after the onset of the symptoms of illness. In 21 blood samples collected at 2 to 9 days of onset, 1 blood sample was real-time RT-PCR positive, the positive rate was 4.76%. All these 21 blood samples were antibody negative.
  
  
  CONCLUSIONS
  Throat swabs and stools samples can be used as A (H1N1) influenza early diagnosis. The length of time duration of positive real-time RT-PCR in throat swabs was longer than stool samples and intermittently releasing of virus were found in throat swabs. Influenza A H1N1 cases showed the presence of small amount of viremia and antibody was negative in early blood samples (< 9 days).
authors.affiliation: Institute for Infectious Disease and Endemic Disease Control, Beijing Center of Disease Control and Prevention, Beijing 100031, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Huang
authors.forename: Wei-Xian
authors.initials: WX
authors.lastname: Shi
authors.forename: Gui-Lan
authors.initials: GL
authors.lastname: Lu
authors.forename: Shu-Juan
authors.initials: SJ
authors.lastname: Cui
authors.forename: Yan-Ning
authors.initials: YN
authors.lastname: Lü
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Tian
authors.forename: Hai-Kun
authors.initials: HK
authors.lastname: Qian
authors.forename: Peng
authors.initials: P
authors.lastname: Yang
authors.forename: Quan-Yi
authors.initials: QY
authors.lastname: Wang
authors.forename: Xing-Huo
authors.initials: XH
authors.lastname: Pang
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000032:analysis*; D002648:Child; D002681:China / Q000453:epidemiology; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology; D008297:Male; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017201:Virus Shedding; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral