title: Concordance of a positive tuberculin skin test and an interferon gamma release assay in bacille Calmette-Guérin vaccinated persons.
abstract: BACKGROUND
  False-positive tuberculin skin test (TST) results due to prior bacille Calmette-Guérin (BCG) vaccination may lead to unnecessary treatment of presumed latent tuberculosis infection (LTBI). Recently approved interferon-gamma release assays (IGRAs) are more specific for LTBI in this group.
  
  
  METHODS
  A total of 316 BCG-vaccinated foreign-born individuals with a positive TST had a commercially available IGRA (QuantiFERON®-TB Gold In-Tube) performed as part of a two-step procedure to determine the need for isoniazid therapy. Baseline demographic information and TST size were recorded and analyzed for characteristics associated with an increased likelihood of having a positive IGRA.
  
  
  RESULTS
  Increasing age, male sex, origin from a country with a high prevalence of tuberculosis (TB), shorter time since arrival in the United States, and increasing TST size were all independently associated with a positive IGRA.
  
  
  CONCLUSIONS
  Patient characteristics and TST size can help determine those at highest risk for LTBI. A two-step procedure for LTBI screening should be considered for foreign-born persons with prior BCG vaccination and a positive TST.
authors.affiliation: Department of Medicine, MetroHealth Medical Center, Cleveland, Ohio 44109, USA. csmahan@gmail.com
authors.forename: C S
authors.initials: CS
authors.lastname: Mahan
authors.forename: D F
authors.initials: DF
authors.lastname: Johnson
authors.forename: C
authors.initials: C
authors.lastname: Curley
authors.forename: F
authors.initials: F
authors.lastname: van der Kuyp
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000995:Antitubercular Agents / Q000627:therapeutic use; D001500:BCG Vaccine; D004641:Emigration and Immigration; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D007538:Isoniazid / Q000627:therapeutic use; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy / Q000208:ethnology / Q000276:immunology / Q000382:microbiology; D016015:Logistic Models; D008214:Lymphocytes / Q000276:immunology / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D016017:Odds Ratio; D009820:Ohio / Q000453:epidemiology; D018579:Patient Selection; D011237:Predictive Value of Tests; D011933:Reagent Kits, Diagnostic; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014374:Tuberculin Test; D019564:Unnecessary Procedures; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents; D001500:BCG Vaccine; D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma; D007538:Isoniazid