title: Interferon-γ release assays for diagnosis of latent tuberculosis infection: evidence in immune-mediated inflammatory disorders.
abstract: OBJECTIVE
  To provide a narrative synthesis of evidence on interferon-gamma release assays (IGRAs) for the diagnosis of latent tuberculosis infection (LTBI) in individuals with immune-mediated inflammatory disorders (IMIDs).
  
  
  RESULTS
  Only a few studies have evaluated IGRAs in IMIDs, and most were small and varied considerably with respect to the use of immunosuppressive medications and types of IMIDs. Current evidence does not clearly suggest that IGRAs are better than tuberculin skin test (TST) in identifying individuals with IMID who could benefit from LTBI treatment. To date, no studies have been done on the predictive value of IGRAs in IMID patients. Important questions remain unanswered as to the impact of immunosuppressive medications and the impact of type of IMID on IGRA performance.
  
  
  CONCLUSIONS
  Despite the lack of clear evidence, there is an increasing tendency for guidelines to prefer IGRA over TST in IMIDs or to recommend both TST and IGRA to enhance sensitivity. We believe the use of either test is acceptable for LTBI screening. Clinicians could consider starting with IGRAs in individuals with a history of Bacille Calmette-Guérin (BCG) vaccination after infancy or with repeated BCG vaccinations. When the index of suspicion for LTBI is high, both IGRA and TST could be performed, especially prior to initiating TNF-α inhibitor therapy. Regardless of the test used, it is important to remember that in the face of immune-suppression, both IGRA and TST can be falsely negative and are thus only diagnostic aids - they will need to be interpreted with other clinical and risk factor data.
authors.affiliation: Department of Medicine, University of California, Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, CA, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Smith
authors.forename: Adithya
authors.initials: A
authors.lastname: Cattamanchi
authors.forename: Karen R
authors.initials: KR
authors.lastname: Steingart
authors.forename: Claudia
authors.initials: C
authors.lastname: Denkinger
authors.forename: Keertan
authors.initials: K
authors.lastname: Dheda
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Winthrop
authors.forename: Madhukar
authors.initials: M
authors.lastname: Pai
mesh_terms: D006801:Humans; D018836:Inflammation Mediators / Q000302:isolation & purification / Q000502:physiology*; D007371:Interferon-gamma / Q000302:isolation & purification / Q000378:metabolism*; D059425:Interferon-gamma Release Tests / Q000379:methods; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology*; D012216:Rheumatic Diseases / Q000175:diagnosis / Q000276:immunology* / Q000473:pathology*; D014374:Tuberculin Test / Q000379:methods* / Q000639:trends
chemical_list: D018836:Inflammation Mediators; D007371:Interferon-gamma