title: Influence of age and nutritional status on the performance of the tuberculin skin test and QuantiFERON-TB gold in-tube in young children evaluated for tuberculosis in Southern India.
abstract: BACKGROUND
  Reliable identification of Mycobacterium tuberculosis infection or tuberculosis (TB) disease in young children is vital to assure adequate preventive and curative treatment. The tuberculin skin test (TST) and IFNγ-release assays may supplement the diagnosis of pediatric TB as cases are typically bacteriologically unconfirmed. However, it is unclear to what extent the performance of TST and QuantiFERON-TB Gold In-Tube (QFT; Cellestis' IFNγ-release assay test) depends on the demographic, clinical and nutritional characteristics of children in whom they are tested.
  
  
  METHODS
  During a 2-year prospective observational study of 4382 neonates in Southern India, children with suspected TB were investigated and classified by a standard TB diagnostic algorithm.
  
  
  RESULTS
  Clinical TB was diagnosed in 13 of 705 children referred for case verification with suspected TB. TST and QFT had a susceptibility for clinical TB of 31% and 23%, respectively, in this group. Children <2 years were more likely to test QFT indeterminate. A height-for-age Z score within the lowest quartile increased the odds ratio (OR) for a positive or indeterminate QFT result [OR 2.46 (1.19-5.06), OR 3.08 (1.10-8.58)], whereas the OR for a positive TST was reduced with a weight-for-height Z score within the lowest quartile [OR 0.17 (0.06-0.47)].
  
  
  CONCLUSIONS
  The sensitivities of the TST and QFT for clinical TB in children <3 years of age were equally poor in this population. Stunted children were more susceptible to Mycobacterium tuberculosis infection and more prone to indeterminate QFT results. TST was less reliable in children with wasting.
authors.affiliation: From the *Center for Immune Regulation, Oslo University Hospital, Rikshospitalet-Radiumhospitalet Medical Center and the University of Oslo, Oslo, Norway; †Division of Epidemiology, Biostatistics and Population Health; ‡Division of Infectious Diseases, St. John's Research Institute, Bangalore, India; §Aeras, Rockville, MD; ¶Department of Paediatrics and Child Health, Desmond Tutu TB Center, Stellenbosch University, Cape Town, South Africa; ‖GlaxoSmithKline Pharma, Vaccines, Copenhagen, Denmark; **Division of Health and Humanities, St. John's Research Institute, Bangalore, India; and ††Department of Clinical Science, University of Bergen and Department of Microbiology, Haukeland University Hospital, Bergen, Norway.
authors.forename: Synne
authors.initials: S
authors.lastname: Jenum
authors.forename: Sumithra
authors.initials: S
authors.lastname: Selvam
authors.forename: Diana
authors.initials: D
authors.lastname: Mahelai
authors.forename: Nelson
authors.initials: N
authors.lastname: Jesuraj
authors.forename: Vicky
authors.initials: V
authors.lastname: Cárdenas
authors.forename: John
authors.initials: J
authors.lastname: Kenneth
authors.forename: Anneke C
authors.initials: AC
authors.lastname: Hesseling
authors.forename: Timothy Mark
authors.initials: TM
authors.lastname: Doherty
authors.forename: Mario
authors.initials: M
authors.lastname: Vaz
authors.forename: Harleen M S
authors.initials: HM
authors.lastname: Grewal
mesh_terms: D000367:Age Factors; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007194:India; D007223:Infant; D059425:Interferon-gamma Release Tests / Q000379:methods*; D008297:Male; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D009752:Nutritional Status; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012882:Skin Tests / Q000379:methods; D014374:Tuberculin Test / Q000379:methods*; D014376:Tuberculosis / Q000175:diagnosis*