Comparison of the baseline level of IFN-γ responses and consistency of QFT-GIT results. The short bar represents the median level of IFN-γ responses in subjects with positive baseline results (3.22 vs. 0.59 IU/ml, p < 0.001). The baseline IFN-γ responses of the subjects with conversions and consistently negative results are plotted for comparison. The responses of four subjects with indeterminate results are not shown. The dashed line represents the diagnostic cut-off ≥ 0.35 IU/ml. IFN-γ responses ≥ 10 IU/ml are shown as 10 IU/ml, IFN-γ responses < 0.00 IU/ml are shown as 0.00 IU/ml. IFN = interferon; QFT-GIT = QuantiFERON®-TB Gold In-Tube.