title: Serial QuantiFERON TB-2G testing over a four-year period in healthcare workers at a city hospital.
abstract: OBJECTIVE
  To evaluate the performance and practicality of QuantiFERON TB-2G (QFT-2G) testing for screening healthcare workers (HCWs) at a city hospital in Japan without a tuberculosis (TB)-specific ward.
  
  
  METHODS
  We performed a chart review of 951 HCWs (251 men and 700 women) who underwent QFT-2G testing as a part of their pre-employment or annual employee screening between April 2007 and March 2010.
  
  
  RESULTS
  The initial QFT-2G test was interpreted as positive in 28 (2.9%) HCWs, negative in 884 HCWs (92.9%) and indeterminate in 39 HCWs (4.1%). During the four-year study period, 37 HCWs were diagnosed as being positive at least once. Nine (0.98%) of the 923 HCWs with indeterminate or negative results on the initial testing converted to a positive status, including 6/479 (1.25%) nurses, 2/100 (2.0%) office staff members and 1/147 (0.68%) physicians. No HCWs with a positive result had a history of tuberculosis (TB) or any apparent contact with active TB patients and did not opt for treatment of latent TB. Seven (25%) of the 28 HCWs who were determined to be positive on the initial testing reverted to an indeterminate or negative status.
  
  
  CONCLUSIONS
  In a series of annual serial QFT-2G tests, some HCWs exhibited conversion and/or reversion. Therefore, caution is required when interpreting mild fluctuations in interferon-γ responses.
authors.affiliation: Department of Respiratory Medicine, Iwata City Hospital, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Uto
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Yasuda
authors.forename: Shinya
authors.initials: S
authors.lastname: Sagisaka
authors.forename: Jun
authors.initials: J
authors.lastname: Sato
authors.forename: Shiro
authors.initials: S
authors.lastname: Imokawa
authors.forename: Noriko
authors.initials: N
authors.lastname: Uemura
authors.forename: Takafumi
authors.initials: T
authors.lastname: Suda
authors.forename: Kingo
authors.initials: K
authors.lastname: Chida
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006282:Health Personnel; D006786:Hospitals, Urban; D006801:Humans; D017053:Infection Control; D059425:Interferon-gamma Release Tests; D007564:Japan; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy; D008297:Male; D008875:Middle Aged