The tuberculin skin test (TST) and interferon-gamma release assays (IGRAs), such as QuantiFERON®-TB Gold Plus (QFT-Plus; Qiagen, Hilden, Germany) and T-SPOT.TB (Oxford Immunotec, Abingdon, UK), are the main diagnostic tests for TB infection.3,4,9–12 Both are indirect tests that measure the cell-mediated immune response to TB. This evidence concerns the gene IFNG and tuberculosis.