Fig. 2. Association of IFN-γ release between two different assays. The association of the IFN-γ responses between the QFT-GIT and ichroma™ IGRA-TB tests was analyzed by Spearman's correlation coefficient. The graph shows a very strong positive correlation of IFN-γ values between the two tests (r=0.91, p<0.001). QFT-GIT, QuantiFERON-TB Gold In-Tube; IGRA, IFN-γ release assay; TB, tuberculosis.