RT Journal Article SR Electronic T1 Performance of QuantiFERON-TB Gold Plus assays in children and adolescents at risk of tuberculosis: a cross-sectional multicentre study JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 1193 OP 1201 DO 10.1136/thoraxjnl-2021-217592 VO 77 IS 12 A1 Soler-Garcia, Aleix A1 Gamell, Anna A1 Pérez-Porcuna, Tomàs A1 Soriano-Arandes, Antonio A1 Santiago, Begoña A1 Tórtola, Teresa A1 Ruiz-Serrano, María Jesús A1 Korta Murua, José Javier A1 Bustillo-Alonso, Matilde A1 Garrote-Llanos, María Isabel A1 Rodríguez-Molino, Paula A1 Piqueras, Ana Isabel A1 Tagarro, Alfredo A1 Monsonís, Manuel A1 Tebruegge, Marc A1 Noguera-Julian, Antoni A1 YR 2022 UL http://thorax.bmj.com/content/77/12/1193.abstract AB Introduction The 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.Data are available upon reasonable request. Data are available upon reasonable request to the corresponding author.