title: Systematic review and metaanalysis: urinary antigen tests for Legionellosis.
abstract: BACKGROUND
  Urinary antigen assays offer simplicity and rapidity in diagnosing Legionnaires' disease, though studies report a range of sensitivities. We conducted a systematic review to assess the test characteristics of Legionella urinary antigen.
  
  
  METHODS
  We searched Medline, Excerpta Medica Database, and bibliographies of retrieved articles. English-language studies were used and included if the absolute number of true-positive, false-negative, true-negative, and false-positive observations were available, and the "gold standards" were described clearly. Two investigators independently reviewed articles and extracted data. Quality was assessed with the Quality Assessment for Diagnostic Accuracy Studies (QUADAS). Sensitivities and specificities were pooled using a random-effects model weighted with the inverse of the SE calculated through the Wald method.
  
  
  RESULTS
  Fifty articles were retrieved for detailed evaluation, and 30 met the inclusion criteria. All but two studies focused on serotype 1 Legionella. Forty assays were reported using six different methodologies, whereas 26 assays used commercial tests, and 14 assays used in-house tests. Study quality was generally low, with average QUADAS scores of 4.4 of a total of 14 points (range, 1 to 9 points). The pooled sensitivity was 0.74 (95% CI, 0.68 to 0.81), and the specificity was 0.991 (95% CI, 0.984 to 0.997). Higher quality studies had lower sensitivity, and there was evidence of publication bias.
  
  
  CONCLUSIONS
  Legionella urinary antigen for serotype 1 appears to have excellent specificity, though modest sensitivity. However, the poor quality of the included studies and the presence of publication bias suggest an overestimation of test performance. High-quality studies are needed.
authors.affiliation: Department of Epidemiology and Healthcare Research, Graduate School of Medicine and Public Health, Kyoto University, Kyoto, Japan; Department of General Internal Medicine, Rakuwakai Otowa Hospital, Kyoto, Japan. Electronic address: smdtshk@gmail.com.
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Shimada
authors.affiliation: Department of General Internal Medicine, Nagoya Daini Red Cross Hospital, Nagoya, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Noguchi
authors.affiliation: Uniformed Services University, Bethesda MD.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Jackson
authors.affiliation: Department of Epidemiology and Healthcare Research, Graduate School of Medicine and Public Health, Kyoto University, Kyoto, Japan; Department of General Internal Medicine, Rakuwakai Otowa Hospital, Kyoto, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Miyashita
authors.affiliation: Department of Epidemiology and Healthcare Research, Graduate School of Medicine and Public Health, Kyoto University, Kyoto, Japan.
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Hayashino
authors.affiliation: Department of General Internal Medicine, Rakuwakai Otowa Hospital, Kyoto, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Kamiya
authors.affiliation: Department of Epidemiology and Healthcare Research, Graduate School of Medicine and Public Health, Kyoto University, Kyoto, Japan.
authors.forename: Shin
authors.initials: S
authors.lastname: Yamazaki
authors.affiliation: Department of General Internal Medicine, Rakuwakai Otowa Hospital, Kyoto, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Matsumura
authors.affiliation: Department of Epidemiology and Healthcare Research, Graduate School of Medicine and Public Health, Kyoto University, Kyoto, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Fukuhara