title: Evaluation of the impact of interferon-gamma release assays on the management of childhood tuberculosis.
abstract: BACKGROUND
  Interferon-gamma release assays are increasingly being used in low-incidence settings, but there is little information on whether test results influence clinical decisions in children.
  
  
  METHODS
  In June 2009, the Montreal Children's Hospital began implementing the QuantiFERON-TB Gold In-Tube (QFT) as a follow-up test to the tuberculin skin test (TST). Pediatric respirologists were asked to document how the QFT result changed their initial clinical management based on the TST.
  
  
  RESULTS
  During a 2-year period, 399 children with TST and QFT results were recruited prospectively. The median age was 13 years. In the cohort, 83% were foreign-born and 82% were Bacille Calmette-Guérin vaccinated. The QFT was negative in 5 of 11 (45.5%) children diagnosed with active tuberculosis (TB). Among 55 TST+/QFT- children evaluated as TB contacts, the negative QFT changed the treatment decision in only 3 (5.5%), and isoniazid was prescribed to the remainder. In 201 TST+/QFT- children from targeted school and immigrant screening programs, a negative QFT result was used to withhold isoniazid in 145 (72.1%) children. These children were followed for 1 year, during which no TB cases occurred. In a multivariable analysis, history of TB contact and TST induration ≥20 mm were associated with fewer changes in clinical decisions.
  
  
  CONCLUSIONS
  Our cohort study showed that pediatric respirologists used negative QFT results to withhold isoniazid in most low-risk children who were referred for a positive TST found through targeted screening programs. In contrast, in almost all TST-positive children who were evaluated as TB contacts, negative QFT results did not change clinical management.
authors: Department of Epidemiology and Biostatistics, McGill University, Canada.
authors: Daphne I
authors: DI
authors: Ling
authors: Claire A
authors: CA
authors: Crépeau
authors: Marieke
authors: M
authors: Dufresne
authors: Shazia
authors: S
authors: Khan
authors: Caroline
authors: C
authors: Quach
authors: Nandini
authors: N
authors: Dendukuri
authors: Kevin
authors: K
authors: Schwartzman
authors: Dick
authors: D
authors: Menzies
authors: Larry C
authors: LC
authors: Lands
authors: Madhukar
authors: M
authors: Pai
mesh_terms: D000293:Adolescent; D000995:Antitubercular Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D059425:Interferon-gamma Release Tests / Q000379:methods*; D007538:Isoniazid / Q000627:therapeutic use; D008297:Male; D014374:Tuberculin Test / Q000379:methods; D014376:Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy
chemical_list: D000995:Antitubercular Agents; D007538:Isoniazid