Comparison of QuantiFERON-TB Gold Plus, QuantiFERON-TB Gold In-Tube, and T-SPOT.TB among patients with tuberculosis

This study evaluated the efficacy of the following interferon (IFN)-γ release assays (IGRAs): QuantiFERON-TB Gold Plus (QFT-Plus), QFT-Gold In-Tube (QFT-GIT), and T-SPOT. TB (T-SPOT) with the quantitative values of IFN-γ response. Blood samples were collected from patients with active tuberculosis (TB), latent TB infection (LTBI), individuals with previous TB infection, and healthy volunteers enrolled between May 2017 and June 2018. IGRAs results were analyzed in 175 subjects (76 had active TB, 14 had LTBI, 35 had prior TB infection, and 50 were healthy). QFT-Plus and QFT-GIT revealed equal efficacy for IFN-γ values, and the IFN-γ response in QFTs tended to increase with the spot counts in T-SPOT, with similar high sensitivities (approximately 90%) in the active TB group. The test concordance of two of three IGRAs was optimal among all subjects (κ coefficients: 0.82–0.96). Additionally, the median quantitative values of IFN-γ with QFT-Plus and QFT-GIT were higher in the active TB group than in the LTBI and previous TB groups. Three IGRAs showed equivalent efficacy with high sensitivities and higher IFN-γ response in active TB group than that in non-active TB group.