Comparison of the QuantiFERON-TB Gold Plus and QuantiFERON-TB Gold In-Tube interferon-γ release assays: A systematic review and meta-analysis

Purpose QuantiFERON-TB Gold Plus (QFT-Plus) is a new generation of QuantiFERON assay that differs from QuantiFERON-TB Gold In-Tube test (QFT-GIT). The aim of this study was to compare the performance of the new FDA-approved QFT-Plus interferon (IFN)-γ release assays (IGRAs) with the QFT-GIT version of this assay. Material and methods We searched all studies published in English in electronic databases, including PubMed, Scopus, and Web of Science. Results The positive proportion of positive results by QFT-Plus was higher than QFT-GIT in cured tuberculosis (TB) cases (82% vs. 73%). The two tests showed a substantial agreement and the majority of the latent tuberculosis infection (LTBI) subjects responded concomitantly to both QFT-Plus and QFT-GIT. However, QFT-Plus showed a stronger association with surrogate measures of TB suspects than QFT-GIT. The QFT-Plus test demonstrated a higher sensitivity than QFT-GIT in the older adults. The sensitivity, specificity, LR+, LR- and DOR overall were 94% (95% CI 89-97), 96% (95% CI 94-98), 24.4 (95% CI 15-39), 0.05 (95% CI 0.03-0.11) and 414 (95% CI 251-685), respectively. The area under summary ROC curve was 0.99 (95% CI 0.97-0.99). Conclusion QFT-Plus performs equivalently to the QFT-GIT for detection of patients at risk for LTBI; however, QFT-Plus test had higher sensitivity than the QFT-GIT test, with similar specificity among the older participants. Higher IFN-γ release in TB2 compared to TB1 might be due to recent LTBI.