title: Cost-effectiveness of interferon-gamma release assay for systematic tuberculosis screening of healthcare workers in low-incidence countries.
abstract: BACKGROUND
  Tuberculosis (TB) is one of the important occupationally acquired infectious diseases in low-incidence countries. Delays in TB diagnosis and treatment among healthcare workers (HCWs) result in costly large-scale TB contact screening among patients and other HCWs.
  
  
  OBJECTIVE
  To assess the cost-effectiveness of TB screening for HCWs using interferon-gamma release assays (IGRAs) compared with tuberculin skin test (TST) and chest x ray (CXR).
  
  
  METHODS
  Markov models were constructed using a hospital payer perspective. The target populations were a hypothetical cohort of 30-year-old HCWs at the time of employment, and a hypothetical cohort of HCWs working on a high-risk ward until 60 years of age. Six strategies were modelled: TST, QuantiFERON-TB Gold In-Tube (QFT), T-SPOT.TB (T-SPOT), TST followed by QFT, TST followed by T-SPOT, and CXR. The main outcome measure of effectiveness was quality-adjusted life-years (QALYs). Costs and QALYs gained per person screened were calculated.
  
  
  RESULTS
  QFT was the most cost-effective strategy at the 'willingness to pay' level of US$ 50,000/QALYs gained (at the time of employment: US$ 334.91, 21.071 QALYs; on a high-risk ward: US$ 1050.32, 20.968 QALYs; values for 2012). Cost-effectiveness was sensitive to latent TB infection (LTBI) rate and bacillus Calmette-Guérin vaccination rate. TST followed by QFT was more cost-effective than QFT when the LTBI rate was <0.026 at the time of employment and <0.08 on a high-risk ward.
  
  
  CONCLUSIONS
  Systematic TB screening using QFT is cost-effective for screening HCWs, and is recommended in low-incidence countries.
authors.affiliation: General Affairs Department, Ota City, Tokyo, Japan. Electronic address: kowadaa@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Kowada
authors.affiliation: Division of Pulmonary Medicine, National Centre for Global Health and Medicine, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Takasaki
authors.affiliation: National Hospital Organization, Tokyo National Hospital, Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Kobayashi
mesh_terms: D000328:Adult; D003362:Cost-Benefit Analysis; D006282:Health Personnel; D006801:Humans; D015994:Incidence; D059425:Interferon-gamma Release Tests / Q000191:economics*; D008390:Markov Chains; D008403:Mass Screening / Q000191:economics / Q000379:methods; D008875:Middle Aged; D009784:Occupational Diseases / Q000175:diagnosis* / Q000191:economics / Q000382:microbiology*; D019057:Quality-Adjusted Life Years; D013902:Radiography, Thoracic / Q000191:economics; D014374:Tuberculin Test / Q000191:economics*; D014376:Tuberculosis / Q000175:diagnosis* / Q000191:economics / Q000635:transmission
keywords: Cost-effectiveness; Healthcare worker; Interferon-gamma release assay; Tuberculosis control