Serial interferon-gamma release assays after rifampicin prophylaxis in a tuberculosis outbreak

Seung Heon Lee, Woo Jin Lew, Hee Jin Kim, Hyun Kyung Lee, Young Min Lee, Chong Hee Cho, Eun Joo Lee, Dong Yeol Lee, Sung Weon Ryu, Soo Yeon Oh, Sin Ok Kim, Tae Sun Shim

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)


Even though some studies have reported the results of serial interferon-gamma release assays (IGRAs) during isoniazid prophylactic treatment, serial results have not been reported after rifampicin prophylaxis. A contact investigation was conducted after a tuberculosis (TB) outbreak in an accommodation facility. The tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube (QFT-GIT) test were performed in 214 contacts with normal chest radiographs. Rifampicin prophylaxis was initiated in TST+/QFT-GIT+ subjects, and the QFT-GIT test was repeated upon completion of 4 months of rifampicin treatment. Among the 214 contacts, the TST and QFT-GIT test results were positive in 67.7% and 56.7%, respectively, and the agreement between the two tests was fair-to-good (78.3%, kappa = 0.55, p < 0.001). The QFT-GIT test was positive in 77% (97/126) of contacts with positive TST results. Rifampicin prophylaxis was completed in 81 subjects with good compliance. Among 74 subjects with valid serial QFT-GIT test results, IFN-γ levels decreased in 97.3% (72/74) of the subjects and QFT-GIT test reversion (positive to negative) was achieved in 31 subjects (41.9%). Subjects without QFT-GIT test reversion had a significantly higher baseline TST induration sizes (18.3 ± 4.8 vs. 14.9 ± 3.4 mm, p < 0.01) and IFN-γ levels (18.6 ± 17.9 vs. 3.2 ± 7.5 IU/mL, p < 0.01) than the subjects with QFT-GIT test reversion. Thus, IGRAs may be useful in evaluating the therapeutic response to rifampicin prophylaxis in TB contacts. However, considering that this was not a controlled study, a prospective controlled study is needed to determine whether rifampicin prophylaxis truly affects QFT-GIT reversion.

Original languageEnglish
Pages (from-to)448-453
Number of pages6
JournalRespiratory Medicine
Issue number3
Publication statusPublished - 2010 Mar
Externally publishedYes


  • Interferon-gamma release assay
  • Rifampicin prophylaxis
  • Serial testing
  • Tuberculosis

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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