Soler García, AleixGamell, AnnaPérez Porcuna, TomàsSoriano Arandes, AntoniSantiago, BegoñaTórtola, TeresaRuiz Serrano, María JesúsKorta Murua, José JavierTagarro García, AlfredoQFT-Plus Study Group of the Spanish Pediatric TB Research NetworkEt al.2022-07-122022-07-122022Soler-García, A., Gamell, A., Pérez-Porcuna, T., Soriano-Arandes, A., Santiago, B., Tórtola, T., Ruiz-Serrano, M. J., Korta Murua, J. J., Bustillo-Alonso, M., Garrote-Llanos, M. I., Rodríguez-Molino, P., Piqueras, A. I., Tagarro, A., Monsonís, M., Tebruegge, M., Noguera-Julián, A., & QFT-Plus Study Group of the Spanish Pediatric TB Research Network (2022). Performance of QuantiFERON- TB Gold Plus assays in children and adolescents at risk of tuberculosis: a cross-sectional multicentre study. Thorax, 77(12), 1193-1201. https://doi.org/10.1136/thoraxjnl-2021-2175920040-63761468-3296http://hdl.handle.net/11268/11466The QuantiFERON-TB Gold Plus (QFT-Plus) assay, which features two antigen-stimulated tubes (TB1 and TB2) instead of a single tube used in previous-generation interferon-gamma release assays (IGRAs), was launched in 2016. Despite this, data regarding the assay's performance in the paediatric setting remain scarce. This study aimed to determine the performance of QFT-Plus in a large cohort of children and adolescents at risk of tuberculosis (TB) in a low-burden setting. Methods: Cross-sectional, multicentre study at healthcare institutions participating in the Spanish Paediatric TB Research Network, including patients <18 years who had a QFT-Plus performed between September 2016 and June 2020. Results: Of 1726 patients (52.8% male, median age: 8.4 years), 260 (15.1%) underwent testing during contact tracing, 288 (16.7%) on clinical/radiological suspicion of tuberculosis disease (TBD), 649 (37.6%) during new-entrant migrant screening and 529 (30.6%) prior to initiation of immunosuppressive treatment. Overall, the sensitivity of QFT-Plus for TBD (n=189) and for latent tuberculosis infection (LTBI, n=195) was 83.6% and 68.2%, respectively. The agreement between QFT-Plus TB1 and TB2 antigen tubes was excellent (98.9%, κ=0.961). Only five (2.5%) patients with TBD had discordance between TB1 and TB2 results (TB1+/TB2-, n=2; TB1-/TB2+, n=3). Indeterminate assay results (n=54, 3.1%) were associated with young age, lymphopenia and elevated C reactive protein concentrations. Conclusions: Our non-comparative study indicates that QFT-Plus does not have greater sensitivity than previous-generation IGRAs in children in both TBD and LTBI. In TBD, the addition of the second antigen tube, TB2, does not enhance the assay's performance substantially.engTuberculosisEnsayojournal article10.1136/thoraxjnl-2021-217592restricted accessAparato respiratorioEnfermedadMedicina preventiva