title: Interferon-gamma release assay improves the diagnosis of tuberculosis in children.
abstract: BACKGROUND
  Interferon-gamma release assays (IGRAs) have been recently developed for the diagnosis of tuberculosis (TB) infection. The aim of the present study was to evaluate the performance of an enzyme-linked immunosorbent assay (ELISA)-based IGRA for detecting TB in children.
  
  
  METHODS
  A prospective study in 336 children at risk for TB infection was carried out. All children were tested with tuberculin skin test (TST) and a commercial ELISA-based IGRA [QuantiFERON-TB Gold In-Tube (Cellestis)].
  
  
  RESULTS
  TST were positive in 58 of 336 (17.3%) and IGRA in 60 of 336 (17.9%) children. Two (0.6%) IGRA results were indeterminate. The overall agreement between the 2 tests was intermediate (86.2%, kappa= 0.533). IGRA was positive in 15 of 16 (93.8%) children with active pulmonary TB. The discordant pattern IGRA-/TST+ was significantly associated with Bacille Calmette-Guérin (BCG) vaccination. Among IGRA+ children (excluding cases of TB disease), TST- were significantly younger than TST+ children.
  
  
  CONCLUSIONS
  The good agreement between positive IGRA and active TB disease suggests a good sensitivity of IGRA. Discrepancies between IGRA and TST can be a result of higher specificity of IGRA that is not influenced by previous BCG vaccination. IGRA may be more sensitive in children younger than 48 months.
authors.affiliation: Department of Pediatrics, University of Florence, Florence, Italy.
authors.forename: Leila
authors.initials: L
authors.lastname: Bianchi
authors.forename: Luisa
authors.initials: L
authors.lastname: Galli
authors.forename: Maria
authors.initials: M
authors.lastname: Moriondo
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Veneruso
authors.forename: Laura
authors.initials: L
authors.lastname: Becciolini
authors.forename: Chiara
authors.initials: C
authors.lastname: Azzari
authors.forename: Elena
authors.initials: E
authors.lastname: Chiappini
authors.forename: Maurizio
authors.initials: M
authors.lastname: de Martino
mesh_terms: D001500:BCG Vaccine; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D008297:Male; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D001500:BCG Vaccine; D007371:Interferon-gamma