Questionable role of interferon-γ assays for smear-negative pulmonary TB in immunocompromised patients

Ji Ye Jung, Ju Eun Lim, Hye jeong Lee, Young Mi Kim, Sang Nae Cho, Se Kyu Kim, Joon Chang, Young Ae Kang

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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.

Original languageEnglish
Pages (from-to)188-196
Number of pages9
JournalJournal of Infection
Issue number2
Publication statusPublished - 2012 Feb 1


All Science Journal Classification (ASJC) codes

  • Microbiology (medical)
  • Infectious Diseases

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