Comparison Of Detection Methods For Latent Infection Of Mycobacterium Tuberculosis In Children

Backgrounds:The performance of interferon-gamma release assays(IGRAs)in detecting tuberculosis(TB)infection has not been systematically compared with that of tuberculin skin testing(TST)among adolescents who born after Bacillus Calmette-Guerin(BCG)booster vaccination was terminated in China.Methods:Based on the baseline survey of a population-based multi-center prospective study,the prevalence of TB infection was estimated for the subgroup population with neonatal BCG vaccination using both TST and QuantiFERON-TB Gold assay(IGRA).Multiple logistic regression analysis was used to identify potential variables related to TST and IGRA positivity,and the strength of the association was estimated by adjusted odds ratio(OR)and 95%confidence interval(CI).The agreement between IGRA and TST was assessed by calculating the corresponding Cohen's kappa coefficient.Results:A total of 2,831 eligible participants aged 5-15 years were included in this study.The prevalence of TST positivity(?10mm)and IGRA positivity was 9.3%(264/2827)and 2.5%(71/2831),respectively.The indeterminate result of IGRA was found to be 2.2%(62/2831).The overall agreement between TST and IGRA was slight(concordance=88.0%;kappa coefficient=0.125).TST,but not IGRA,was found to be positively associated with BCG vaccination with an adjusted OR of 1.71[95%CI:1.26-2.31].A history of close contact with patients of active TB was significantly associated with positivity for both TST and IGRA.Conclusion:TST performance was found to be influenced by BCG neonatal vaccination.In China,two-step approach(TST screening followed by IGRA confirmation)might be considered for TB infection testing among high-risk subgroups in adolescents,such as close contacts.