title: Interferon-gamma release assays for the detection of Mycobacterium tuberculosis infection in children with cancer.
abstract: METHODS
  The paediatric oncology unit at Tygerberg Children's Hospital, South Africa.
  
  
  OBJECTIVE
  To assess the use of the tuberculin skin test (TST) and two commercial interferon-gamma release assays (IGRAs) for the detection of Mycobacterium tuberculosis infection in children with cancer before initiating chemotherapy treatment.
  
  
  METHODS
  Prospective hospital-based study, including children newly diagnosed with cancer; all underwent TST and IGRA testing.
  
  
  RESULTS
  Of the 34 children enrolled, seven (17.6%) tested positive with either test: TST (3/7, 8.8%), T-SPOT.TB (n = 6, 17.6%) and QuantiFERON-TB Gold In-Tube (QFT-G; n = 3, 8.8%). T-SPOT.TB assay results were negative in 17 (50.0%) and indeterminate in four (11.8%) children. Six T-SPOT.TB tests could not be completed due to low cell counts (<100,000 per well), and one clotted. QFT-G results were negative in 26 (76.5%) and indeterminate in five (14.7%).
  
  
  CONCLUSIONS
  TST and IGRAs were frequently discordant, with fewer positive results than expected. T-SPOT.TB produced more positive results, but inadequate cell counts were a particular problem. The sample size was too small to comment with confidence on test accuracy. All latent TB infection tests appear to perform sub-optimally in this group of children, and therefore none of them can be used in isolation to confirm or disprove TB infection.
authors.affiliation: Department of Paediatrics and Child Health, Tygerberg Children's Hospital, Tygerberg, South Africa. cs@sun.ac.za
authors.forename: D C
authors.initials: DC
authors.lastname: Stefan
authors.forename: A
authors.initials: A
authors.lastname: Dippenaar
authors.forename: A K
authors.initials: AK
authors.lastname: Detjen
authors.forename: H S
authors.initials: HS
authors.lastname: Schaaf
authors.forename: B J
authors.initials: BJ
authors.lastname: Marais
authors.forename: B
authors.initials: B
authors.lastname: Kriel
authors.forename: L
authors.initials: L
authors.lastname: Loebenberg
authors.forename: G
authors.initials: G
authors.lastname: Walzl
authors.forename: A C
authors.initials: AC
authors.lastname: Hesseling
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007223:Infant; D007371:Interferon-gamma / Q000097:blood*; D055985:Latent Tuberculosis / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D009369:Neoplasms / Q000097:blood / Q000150:complications* / Q000175:diagnosis; D011446:Prospective Studies; D015203:Reproducibility of Results; D013019:South Africa / Q000453:epidemiology; D013997:Time Factors
chemical_list: D007371:Interferon-gamma