title: Clinical predictors for diagnosing pandemic (H1N1) 2009 and seasonal influenza (H3N2) in fever clinics in Beijing, China.
abstract: OBJECTIVE
  Symptomatic predictors of influenza could assess risks and improve decisions about isolation and outpatient treatment. To develop such predictors, we undertook a prospective analysis of pandemic (H1N1) 2009 and seasonal influenza (H3N2) in patients attending fever clinics.
  
  
  METHODS
  From 1 May 2009 to 1 January 2010, all adult patients admitted to fever clinics for suspected influenza, confirmed by real time RT-PCR, were enrolled. Predictors of influenza virus infection were selected with logistic regression models. Measures of sensitivity, specificity, positive and negative likelihood ratios (LRs) were calculated to identify the best predictors.
  
  
  RESULTS
  The clinical features and routine blood test results of influenza (H1N1) 2009 and seasonal influenza were similar. The positive and negative LRs of current US CDC influenza-like illness (ILI) criteria were modest in predicting influenza infection. Our modified clinic predictors improved the ability of the positive and negative LRs to recognize pandemic (H1N1) 2009 and seasonal influenza. The revised criteria are: fever >38 °C accompanied by at least one of the following-cough, arthralgia or relative lymphopenia.
  
  
  CONCLUSIONS
  Patients with symptoms and signs that meet the new criteria are likely to have influenza and timely antiviral therapy may be appropriate. In addition, physicians should ascertain if influenza is circulating within the community or if there is a contact history of influenza and combine this information with the newly developed criteria to clinically diagnose influenza.
authors.affiliation: Department of Epidemiology and Bio-statistics, School of Public Health, Peking University Health Science Center, Beijing, China.
authors.forename: Xiao Qiu
authors.initials: XQ
authors.lastname: Dai
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Tuo Hong
authors.initials: TH
authors.lastname: Zhang
authors.forename: Xue Song
authors.initials: XS
authors.lastname: Yang
authors.forename: Song Lin
authors.initials: SL
authors.lastname: Li
authors.forename: Xiao Guang
authors.initials: XG
authors.lastname: Li
authors.forename: Yu Ling
authors.initials: YL
authors.lastname: Li
authors.forename: Hai San
authors.initials: HS
authors.lastname: Kadeerbai
authors.forename: Huang
authors.initials: H
authors.lastname: Wu
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D053122:Influenza A Virus, H3N2 Subtype; D007251:Influenza, Human / Q000175:diagnosis* / Q000453:epidemiology / Q000821:virology; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D058873:Pandemics; D011237:Predictive Value of Tests; D011446:Prospective Studies; D055815:Young Adult