title: Combined use of a TST and the T-SPOT®.TB assay for latent tuberculosis infection diagnosis before anti-TNF-α treatment.
abstract: BACKGROUND
  Diagnosis of latent tuberculosis infection (LTBI) before anti-tumour-necrosis factor (anti-TNF) treatment is important. However, the tuberculin skin test (TST) has limitations, and the role of interferon-gamma release assays has not yet been determined.
  
  
  OBJECTIVE
  To evaluate the combined use of TST and the T-SPOT(®).TB (T-SPOT) assay prior to anti-TNF treatment.
  
  
  METHODS
  From July 2004 to March 2008, 281 patients were treated with anti-TNF agents. TST and T-SPOT were performed simultaneously at baseline. LTBI was defined as a positive TST of ≥10 mm induration or as a positive T-SPOT if TST was ≥5 mm but <10 mm. LTBI treatment was initiated, and patients were followed until August 2010.
  
  
  RESULTS
  Positivity rates for TST and T-SPOT were respectively 33.6% (94/280) and 69.1% (186/269). LTBI treatment was initiated in 35.9% (101/281) of the patients, and active TB developed in 2.1% (6/281). Among the six TB patients, three were TST-negative at baseline and received no LTBI treatment, whereas all four who underwent T-SPOT showed positive results at baseline.
  
  
  CONCLUSIONS
  In a TB-prevalent country, TST-defined LTBI diagnosis and treatment seem to be limited in preventing the development of TB before anti-TNF treatment. Further studies for T-SPOT alone or the combined use of TST and T-SPOT (either test positive strategy) for detecting LTBI are necessary.
authors.affiliation: Department of Pulmonary and Critical Care Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea.
authors.forename: Y J
authors.initials: YJ
authors.lastname: Jung
authors.forename: J
authors.initials: J
authors.lastname: Lyu
authors.forename: B
authors.initials: B
authors.lastname: Yoo
authors.forename: C-K
authors.initials: CK
authors.lastname: Lee
authors.forename: Y-G
authors.initials: YG
authors.lastname: Kim
authors.forename: S-K
authors.initials: SK
authors.lastname: Yang
authors.forename: J-S
authors.initials: JS
authors.lastname: Byeon
authors.forename: K J
authors.initials: KJ
authors.lastname: Kim
authors.forename: B D
authors.initials: BD
authors.lastname: Ye
authors.forename: K-H
authors.initials: KH
authors.lastname: Lee
authors.forename: S-D
authors.initials: SD
authors.lastname: Lee
authors.forename: W S
authors.initials: WS
authors.lastname: Kim
authors.forename: D S
authors.initials: DS
authors.lastname: Kim
authors.forename: T S
authors.initials: TS
authors.lastname: Shim
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007155:Immunologic Factors / Q000627:therapeutic use*; D059425:Interferon-gamma Release Tests / Q000379:methods*; D055985:Latent Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy; D008297:Male; D012189:Retrospective Studies; D014374:Tuberculin Test / Q000379:methods*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors*
chemical_list: D007155:Immunologic Factors; D014409:Tumor Necrosis Factor-alpha