Tuberculosis Research and Treatment (Jan 2014)

Tuberculin Skin Tests versus Interferon-Gamma Release Assays in Tuberculosis Screening among Immigrant Visa Applicants

  • Stella O. Chuke,
  • Nguyen Thi Ngoc Yen,
  • Kayla F. Laserson,
  • Nguyen Huu Phuoc,
  • Nguyen An Trinh,
  • Duong Thi Cam Nhung,
  • Vo Thi Chi Mai,
  • An Dang Qui,
  • Hoang Hoa Hai,
  • Le Thien Huong Loan,
  • Warren G. Jones,
  • William C. Whitworth,
  • J. Jina Shah,
  • John A. Painter,
  • Gerald H. Mazurek,
  • Susan A. Maloney

DOI
https://doi.org/10.1155/2014/217969
Journal volume & issue
Vol. 2014

Abstract

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Objective. Use of tuberculin skin tests (TSTs) and interferon gamma release assays (IGRAs) as part of tuberculosis (TB) screening among immigrants from high TB-burden countries has not been fully evaluated. Methods. Prevalence of Mycobacterium tuberculosis infection (MTBI) based on TST, or the QuantiFERON-TB Gold test (QFT-G), was determined among immigrant applicants in Vietnam bound for the United States (US); factors associated with test results and discordance were assessed; predictive values of TST and QFT-G for identifying chest radiographs (CXRs) consistent with TB were calculated. Results. Of 1,246 immigrant visa applicants studied, 57.9% were TST positive, 28.3% were QFT-G positive, and test agreement was 59.4%. Increasing age was associated with positive TST results, positive QFT-G results, TST-positive but QFT-G-negative discordance, and abnormal CXRs consistent with TB. Positive predictive values of TST and QFT-G for an abnormal CXR were 25.9% and 25.6%, respectively. Conclusion. The estimated prevalence of MTBI among US-bound visa applicants in Vietnam based on TST was twice that based on QFT-G, and 14 times higher than a TST-based estimate of MTBI prevalence reported for the general US population in 2000. QFT-G was not better than TST at predicting abnormal CXRs consistent with TB.