title: Use of the QuantiFERON-TB Gold test for screening tuberculosis contacts and predicting active disease.
abstract: OBJECTIVE
  To evaluate the performance of the QuantiFERON(R)-TB Gold (QFT-G) test for screening tuberculosis (TB) contacts and estimating their risk of progressing to active TB disease.
  
  
  METHODS
  Data on clinical progression to active disease were collected from public health centres 2 years after close contacts of TB cases had been QFT-G-tested.
  
  
  RESULTS
  Among 3102 contacts observed, 419 were QFT-G-positive, and isoniazid (INH) treatment was initiated in 323. Twenty (4.8%) of these 419 developed TB disease. Among 2683 QFT-G-negative persons, 19 were diagnosed with TB (0.7%) during the average follow-up period of 1.6 years. The estimated sensitivity of QFT-G in detecting contacts who would progress to active TB was 51%, or 64% allowing for the effects of INH treatment. Among the QFT-G-negative contacts, all those who developed TB disease were contacts of highly infectious cases. Large-scale tuberculin skin testing was not available.
  
  
  CONCLUSIONS
  TB incidence among QFT-G-positive contacts was higher than among QFT-G-negative contacts, but the number of TB cases among QFT-G-negative contacts is non-negligible, especially among contacts of highly infectious cases.
authors.affiliation: First Clinical Department, Fukujuji Hospital, Tokyo, Japan. yoshiyama1962@yahoo.co.jp
authors.forename: T
authors.initials: T
authors.lastname: Yoshiyama
authors.forename: N
authors.initials: N
authors.lastname: Harada
authors.forename: K
authors.initials: K
authors.lastname: Higuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Sekiya
authors.forename: K
authors.initials: K
authors.lastname: Uchimura
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D016358:Contact Tracing; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D007371:Interferon-gamma / Q000032:analysis*; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014374:Tuberculin Test / Q000379:methods; D014376:Tuberculosis / Q000175:diagnosis* / Q000503:physiopathology; D055815:Young Adult
chemical_list: D007371:Interferon-gamma