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Tuberculosis Research and Treatment
Volume 2014 (2014), Article ID 217969, 11 pages
http://dx.doi.org/10.1155/2014/217969
Research Article

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

1Northrop Grumman Information Systems Sector, 2800 Century Parkway NE, Atlanta, GA 30345, USA
2Division of Tuberculosis Elimination, Centers for Disease Control and Prevention (CDC), Mail Stop E-10, 1600 Clifton Road NE, Atlanta, GA 30333, USA
3Cho Ray Hospital, 201B Nguyen Chi Thanh Street, District 5, Ho Chi Minh City, Vietnam
4Center for Global Health, CDC, Mail Stop D-68, 1600 Clifton Road NE, Atlanta, GA 30333, USA
5International Organization for Migration (IOM), 1B Pham Ngoc Thach District 1, Ho Chi Minh City, Vietnam
6International Organization for Migration (IOM), P.O. Box 55040, Westlands, Nairobi 00200, Kenya
7Division of Global Migration and Quarantine, CDC, Mail Stop E-03, 1600 Clifton Road NE, Atlanta, GA 30333, USA
8Department of Family & Community Medicine, University of California, San Francisco, 500 Parnassus Avenue, MU 3E, San Francisco, CA 94143, USA
9Genentech, Inc., 1 DNA Way, South San Francisco, CA 94080, USA

Received 30 September 2013; Accepted 15 January 2014; Published 6 March 2014

Academic Editor: Juraj Ivanyi

Copyright © 2014 Stella O. Chuke et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

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.