title: Interferon Gamma Release Assay-Guided Latent Tuberculosis Prophylaxis in Israel.
abstract: BACKGROUND
  Determining the accuracy of interferon gamma-release assays (IGRAs) is difficult due to the lack of a gold standard test for diagnosing latent tuberculosis (LTB).
  
  
  OBJECTIVE
  To analyze the guidelines used for interpreting IGRAs in determining prophylactic treatment management for latent tuberculosis (LTB) in Israel.
  
  
  METHODS
  We analyzed the retrospective data of 367 subjects who were referred to our laboratory during the period 2007-2011 for QuantiFERON Test-Gold In Tube (QFT-GIT) tests because of suspected LTB. Demographics and clinical data were retrieved from a questionnaire at enrollment, and 166/367 (45%) were further interviewed by phone in order to complete follow-up information on prophylactic TB treatment.
  
  
  RESULTS
  The majority of subjects (116/166, 69.9%, P (P < 0.0001) were spared prophylactic treatment subsequent to QFT-GIT testing. Subjects with negative QFT-GIT and positive tuberculin skin test (TST) results who were BCG-vaccinated had the lowest treatment rates (6/68, 8.8%, P < 0.0001). Most BCG-vaccinated subjects with positive TST and negative QFT-GIT test results received treatment with anti-tumor necrosis factor-alpha (TNFα) (17/19, 89.5%, P = 0.004). We found more negative QFT-GIT test results in subjects who were receiving anti-TNFα or steroid and other immunosuppressive treatment prior to testing (11/11, 100%, P = 0.029; 22/26, 84.6%, P = 0.06; 15/17, 88%, P = 0.06, respectively).
  
  
  CONCLUSIONS
  Deciding on LTB prophylactic treatment in Israel is highly influenced by QFT-GIT test results. QFT-GIT findings contribute to clinical decisions, but their interpretation must also consider the patient's medical history and clinical characteristics.
authors.forename: Einat
authors.initials: E
authors.lastname: Fireman-Klein
authors.forename: Avraham
authors.initials: A
authors.lastname: Man
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Schwartz
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Fireman
mesh_terms: D000293:Adolescent; D000328:Adult; D001500:BCG Vaccine / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007223:Infant; D059425:Interferon-gamma Release Tests / Q000379:methods*; D007557:Israel; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D012189:Retrospective Studies; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors; D055815:Young Adult
chemical_list: D001500:BCG Vaccine; D007166:Immunosuppressive Agents; D014409:Tumor Necrosis Factor-alpha