title: Questionable role of interferon-γ assays for smear-negative pulmonary TB in immunocompromised patients.
abstract: OBJECTIVE
  The purpose of this study was to examine the usefulness of the TST and the interferon-γ release assays (IGRA) for diagnosing smear-negative pulmonary TB in immunocompromised patients in an intermediate TB burden.
  
  
  METHODS
  We conducted a prospective study enrolling 119 immunocompromised participants with suspected smear-negative pulmonary TB in Seoul, South Korea. Clinical assessment, TST, QuantiFERON-TB Gold In Tube (QFT-GIT), and T-SPOT.TB were performed in immunosuppressed condition.
  
  
  RESULTS
  All participants were categorized according to the type of immunosuppression: 29 patients with diabetes mellitus, 53 with malignancy, 23 with taking immunosuppressive drugs, and 14 with end stage renal disease. IGRA sensitivity and specificity (95% CI) were: QFT-GIT [59.0% (44.9-72.0)] and [61.3% (54.4-67.6)] and T-SPOT.TB [72.0% (54.2-86.2)] and [42.3% (33.8-49.1)], respectively. For TST, sensitivity was 41.2% (28.3-50.8) and specificity was 91.8% (85.8-96.30). The sensitivities of the three diagnostic methods tended to be lower in the immunosuppressive drug group than in other groups (QFT-GIT 11.1%, T-SPOT.TB 40.0% and TST 25.0% in patients with taking immunosuppressive drugs). Among 111 patients who underwent a chest CT examination, there were no significant differences in the CT findings between the immunocompromised TB and non-TB patients.
  
  
  CONCLUSIONS
  The IGRAs and TST had no value as a single test either to rule-in or rule-out active TB in immunocompromised patients in an intermediate burden.
authors: Department of Internal Medicine, Yonsei University College of Medicine, Seoul, South Korea.
authors: Ji Ye
authors: JY
authors: Jung
authors: Ju Eun
authors: JE
authors: Lim
authors: Hye-Jeong
authors: HJ
authors: Lee
authors: Young Mi
authors: YM
authors: Kim
authors: Sang-Nae
authors: SN
authors: Cho
authors: Se Kyu
authors: SK
authors: Kim
authors: Joon
authors: J
authors: Chang
authors: Young Ae
authors: YA
authors: Kang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D007371:Interferon-gamma / Q000032:analysis; D059425:Interferon-gamma Release Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011933:Reagent Kits, Diagnostic; D056910:Republic of Korea; D012680:Sensitivity and Specificity; D014374:Tuberculin Test / Q000379:methods*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000276:immunology
chemical_list: D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma