In this issue of CHEST (see page 1461), Park and colleagues9 report on a study from South Korea, where health-care workers (HCWs) underwent monthly QuantiFERON-TB Gold In-Tube assays (QFT-GITs) over a 1-year period. They found a high frequency of QFT-GIT conversions and reversions in this intermediate TB burden country, with nearly one-half of the participants showing inconsistent results over time. The authors speculate that such inconsistent patterns could be due to a combination of several factors, including poor reproducibility, new infections because of exposure, true reversions, or intermittent secretion of TB antigens that may stimulate T-cell responses. This study, while highly consistent with previous literature,8 adds value because it includes the largest number of repeat tests over the longest period of time. Taken together with all the literature on serial testing and reproducibility,5-8 we now have a fairly nuanced understanding of what to expect when IGRAs are repeated.