title: Use of the QuantiFERON®-TB Gold in Tube test for screening TB contacts and predictive value for active TB.
abstract: BACKGROUND
  This study estimated the incidence of progression to active tuberculosis (TB) among contacts categorized by QuantiFERON(®)-TB Gold in Tube (QFT-GIT) test results and investigated other risk factors related to progression to TB.
  
  
  METHODS
  Contacts of patients with TB were tested using QFT-GIT and were followed up every 6 months at public health centers to detect clinical progression to TB.
  
  
  RESULTS
  Analysis of a retrospective cohort revealed that, of the 625 contacts, 168 were QFT-GIT positive and 457 were negative. Of these, 10 (6%) QFT-GIT-positive and two (0.4%) QFT-GIT-negative contacts progressed to TB during the follow-up period (p < 0.01, statistically significant). Multivariable logistic regression analysis revealed that QFT-GIT positivity (p < 0.01), contact of index patients with many other positive contacts (p < 0.01), household contact (p = 0.014), and untreated latent TB infection (p = 0.047) were independent risk factors for progression to TB during an average follow-up period of 637 days.
  
  
  CONCLUSIONS
  Progression to TB among QFT-GIT-positive contacts was higher than among QFT-GIT-negative contacts. Other independent risk factors for progression to TB were index cases with more QFT-GIT-positive contacts as well as household contacts.
authors.affiliation: From the 1 Respiratory Diseases Center, Fukujuji Hospital , Kiyose City , Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshiyama
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Harada
authors.forename: Kazue
authors.initials: K
authors.lastname: Higuchi
authors.forename: Masami
authors.initials: M
authors.lastname: Saitou
authors.forename: Seiya
authors.initials: S
authors.lastname: Kato
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D016358:Contact Tracing; D018450:Disease Progression; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D059425:Interferon-gamma Release Tests / Q000295:instrumentation / Q000379:methods; D007564:Japan / Q000453:epidemiology; D055985:Latent Tuberculosis / Q000175:diagnosis; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012307:Risk Factors; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology; D055815:Young Adult
keywords: QFT-GIT; Tuberculosis; diseases; infection; interferon-gamma release test