Discordance of Tuberculin Skin Test and Interferon Gamma Release Assay in Recently Exposed Household Contacts of Pulmonary TB Cases in Brazil

• DOI: 10.1371/journal.pone.0096564
• Publication Date: 2014-05-12T21:27:47Z
• Authors: Rodrigo Ribeiro-R...; Soyeon Kim; Flávia Dias Coelh...; Aleksandra Uzelac; Lauren Collins; Moíses Palaci; David Alland; Reynaldo Dietze; Jerrold J. Ellner; Edward Jones-López; Padmini Salgame
• Keywords: Concordance; QuantiFERON; Tuberculosis diagnosis; Gold standard (test)

Interferon-gamma (IFN-γ) release assays (IGRAs) such as the Quantiferon Gold In-tube test are in vitro that measure IFN-γ from T cells response to M. tuberculosis (Mtb)-specific antigens. Unlike tuberculin skin (TST), IGRA is specific and able distinguish Mtb-infection BCG vaccination. In this study we evaluated concordance between TST efficacy of diagnosing new Mtb infection household contacts (HHC) pulmonary (PTB) cases. A total 357 HHC TB cases Vitória, Brazil were studied. was performed within 2 weeks following enrollment if negative a second at 8-12 weeks. categorized initially positive (TST+), persistently (TST-), or converters (TSTc), latter representative infection. results 82% TST+, 48% TSTc, 12% TST-, indicating poor two among each category. Evaluating CXCL10 levels subset supernatants lowering cutoff value define increased agreement results. However, ROC curves demonstrated resulted trade-off sensitivity specificity with respect TST. Together, findings suggest until basis for discordance fully understood, it may be necessary utilize both tests diagnose recently exposed HHC. Operationally, HHC, useful employ lower allow closer monitoring potential conversion.