title: Programmatic impact of QuantiFERON-TB Gold In-Tube implementation on latent tuberculosis diagnosis and treatment in a public health clinic.
abstract: BACKGROUND
  QuantiFERON-TB Gold In-Tube (QFT-GIT) is considered an alternative to the tuberculin skin test (TST) for the diagnosis of tuberculosis (TB) infection, but the programmatic impact of QFT-GIT implementation is largely unknown. In March, 2010, the Baltimore City Health Department (BCHD) introduced routine QFT-GIT testing for individuals referred to the TB program for suspected latent TB infection (LTBI).
  
  
  METHODS
  Retrospective study comparing LTBI diagnosis and treatment during the 13 months before and after QFT-GIT implementation at the BCHD TB clinic.
  
  
  RESULTS
  607 and 750 individuals were referred by community-providers for suspected LTBI in the pre- and post-QFT-GIT periods, respectively. Most individuals in the pre- and post-QFT-GIT periods were referred on the basis of a positive TST (597/607 [98%] vs. 690/750 [92%], respectively) and were foreign-born (363/607[59%] vs. 507/750[68%], respectively). BCHD performed QFT-GIT testing for 375/543 (69%) eligible individuals in the post-QFT-GIT period, of which 185 (49%) were positive, 178 (47%) were negative, 1 (0.25%) was indeterminate, and 11 (3%) did not yield results. Concordance of QFT-GIT with TST was low (183/352[52%]). Foreign-born individuals had higher proportions of QFT-GIT positivity (57%) than US-born individuals (36%; AOR 3.3 [95%CI 1.7-6.2]). Significantly fewer individuals received a final diagnosis of LTBI in the post-QFT-GIT period (397/567 [70%]) compared to the pre-QFT-GIT period (445/452 [98%], p<0.001). In the post-QFT-GIT period, only 230/399 (58%) of those receiving QFT-GIT testing had a final diagnosis of LTBI, while 167/168 (99%) of those without QFT-GIT testing were diagnosed with LTBI (p<0.001). There was no difference in treatment initiation between those with and without QFT-GIT testing (175/230 [76%]) vs. 133/167 [80%], respectively) in the post-QFT-GIT period.
  
  
  CONCLUSIONS
  QFT-GIT implementation for LTBI evaluation in a public health clinic significantly reduced the proportion of referred individuals in whom LTBI was diagnosed. QFT-GIT testing had no impact on treatment initiation or completion among those diagnosed with LTBI.
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland, USA. mshah28@jhmi.edu
authors.forename: Maunank
authors.initials: M
authors.lastname: Shah
authors.forename: Danielle
authors.initials: D
authors.lastname: DiPietro
authors.forename: Adena
authors.initials: A
authors.lastname: Greenbaum
authors.forename: Sherry
authors.initials: S
authors.lastname: Ketemepi
authors.forename: Maria
authors.initials: M
authors.lastname: Martins-Evora
authors.forename: Vincent
authors.initials: V
authors.lastname: Marsiglia
authors.forename: Susan E
authors.initials: SE
authors.lastname: Dorman
mesh_terms: D000328:Adult; D000554:Ambulatory Care Facilities; D015142:Baltimore; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D012189:Retrospective Studies; D014374:Tuberculin Test / Q000379:methods; D014481:United States / Q000453:epidemiology
chemical_list: D007371:Interferon-gamma