Predictive Value of a Whole Blood IFN-γ Assay for the Development of Active Tuberculosis Disease after Recent Infection with <i>Mycobacterium tuberculosis</i>

Results suggest that QFT is a more accurate indicator of the presence of LTBI than the TST and provides at least the same sensitivity for detecting those who will progress to active TB. The high rate of progression to active TB of those who are QFT positive (14.6%), which is far greater than the 2.3% found for those who are TST positive, has health and economic implications for enhanced TB control, particularly if this higher progression rate is seen in studies of other at-risk populations.