title: Interferon-γ release assays for active pulmonary tuberculosis diagnosis in adults in low- and middle-income countries: systematic review and meta-analysis.
abstract: BACKGROUND
  The diagnostic value of interferon-γ release assays (IGRAs) for active tuberculosis in low- and middle-income countries is unclear.
  
  
  METHODS
  We searched multiple databases for studies published through May 2010 that evaluated the diagnostic performance of QuantiFERON-TB Gold In-Tube (QFT-GIT) and T-SPOT.TB (T-SPOT) among adults with suspected active pulmonary tuberculosis or patients with confirmed cases in low- and middle-income countries. We summarized test performance characteristics with use of forest plots, hierarchical summary receiver operating characteristic (HSROC) curves, and bivariate random effects models.
  
  
  RESULTS
  Our search identified 789 citations, of which 27 observational studies (17 QFT-GIT and 10 T-SPOT) evaluating 590 human immunodeficiency virus (HIV)-uninfected and 844 HIV-infected individuals met inclusion criteria. Among HIV-infected patients, HSROC/bivariate pooled sensitivity estimates (highest quality data) were 76% (95% confidence interval [CI], 45%-92%) for T-SPOT and 60% (95% CI, 34%-82%) for QFT-GIT. HSROC/bivariate pooled specificity estimates were low for both IGRA platforms among all participants (T-SPOT, 61% [95% CI, 40%-79%]; QFT-GIT, 52% [95% CI, 41%-62%]) and among HIV-infected persons (T-SPOT, 52% [95% CI, 40%-63%]; QFT-GIT, 50% [95% CI, 35%-65%]). There was no consistent evidence that either IGRA was more sensitive than the tuberculin skin test for active tuberculosis diagnosis.
  
  
  CONCLUSIONS
  In low- and middle-income countries, neither the tuberculin skin test nor IGRAs have value for active tuberculosis diagnosis in adults, especially in the context of HIV coinfection.
authors: Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, San Francisco, CA, USA.
authors: John Z
authors: JZ
authors: Metcalfe
authors: Charles K
authors: CK
authors: Everett
authors: Karen R
authors: KR
authors: Steingart
authors: Adithya
authors: A
authors: Cattamanchi
authors: Laurence
authors: L
authors: Huang
authors: Philip C
authors: PC
authors: Hopewell
authors: Madhukar
authors: M
authors: Pai
mesh_terms: D000328:Adult; D015658:HIV Infections / Q000382:microbiology; D006801:Humans; D059425:Interferon-gamma Release Tests; D011237:Predictive Value of Tests; D012959:Socioeconomic Factors; D014374:Tuberculin Test / Q000379:methods*; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology / Q000821:virology