title: Use of QuantiFERON-TB Gold to investigate tuberculosis contacts in a high school.
abstract: OBJECTIVE
  QuantiFERON-TB Gold (QFT-G) was employed in a contact investigation in a high school to evaluate its performance in adolescents.
  
  
  METHODS
  Students of the same school grade as the index case were screened with tuberculin skin test (TST) and CXR examination as an initial contact investigation. QFT-G was performed for students demonstrating a positive TST (erythema larger than 30 mm).
  
  
  RESULTS
  Of 349 students whose TST was completed, 95 had positive TST responses, although the distribution of TST responses was similar for both high and low exposure groups. In contrast, only four of the 88 TST-positive students tested with QFT-G were positive by this test, and three of these were from the high exposure group. Chemoprophylaxis was provided to only those four QFT-G-positive students. Follow up of the 91 students who were TST-positive, but QFT-G-negative (or not tested), for more than 3.5 years revealed that none have developed active tuberculosis.
  
  
  CONCLUSIONS
  QFT-G appears more specific than TST as contacts with positive TST and negative QFT-G responses were not offered prophylaxis and none developed tuberculosis during 3.5 years of follow up. The replacement of TST with QFT-G, or perhaps combined use of TST and QFT-G, may be more useful in diagnosing true infection and thus reducing the number of subjects indicated for chemoprophylaxis.
authors.affiliation: Research Institute of Tuberculosis, Tokyo, Japan. higuchi@jata.or.jp
authors.forename: Kazue
authors.initials: K
authors.lastname: Higuchi
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Harada
authors.forename: Toru
authors.initials: T
authors.lastname: Mori
authors.forename: Yukie
authors.initials: Y
authors.lastname: Sekiya
mesh_terms: D000293:Adolescent; D004196:Disease Outbreaks / Q000517:prevention & control*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008403:Mass Screening / Q000379:methods*; D012189:Retrospective Studies; D012574:Schools; D013334:Students / Q000706:statistics & numerical data*; D014373:Tuberculin; D014374:Tuberculin Test / Q000379:methods*; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology
chemical_list: D014373:Tuberculin