Multicenter study of QuantiFERON®-TB Gold Plus in patients with active tuberculosis

Setting: QuantiFERONw-TB Gold Plus (QFT-Plus), recently approved for use in the United States, is a newgeneration QuantiFERON assay that differs from its predecessors in that it uses an additional antigen tube containing peptides to elicit both CD8 ⁺ and CD4 ⁺ Tlymphocyte responses. Objective : To assess the sensitivity of QFT-Plus compared with QuantiFERON®-TB Gold In-Tube (QFT-GIT) in participants with active TB. Design: Adult patients with active TB at three US and two Japanese sites were eligible for this study if they had culture-confirmed TB and were either untreated or had received ≤14 days of anti-tuberculosis treatment. Results : We enrolled 164 participants, nine of whom had indeterminate results. Excluding indeterminate values, there were 150 QFT-GIT-positive results among 159 tests and 146 QFT-Plus-positive results among 157 tests, with sensitivities of respectively 94.3% (95%CI 89.5-97.4) and 93.02% (95%CI 87.8-96.5%). The estimated sensitivities for the two tests were not significantly different (P=0.16). Overall test agreement was 98.7%, with a κ statistic of 0.89 (95%CI 0.75-1.00). Conclusion: In this multisite study, we found that QFT-Plus had similar sensitivity to QFT-GIT in adult patients with active TB.