Comparison of Two Interferon-γ Assays and Tuberculin Skin Test for Tracing Tuberculosis Contacts

Blood test results were associated with exposure, whereas the TST was not. A possible lack of sensitivity of IFN-gamma assays in detecting individuals with TST of 15 mm or greater, despite negative bacillus Calmette-Guérin vaccination status, warrants further investigation into alternative cutoff values.