关键词: 潜伏性结核感染, γ-干扰素释放试验, 社区筛查, 诊断性能, 无结核社区

Abstract: Objective Given the high cost of imported reagents for community-based latent tuberculosis infection （LTBI） screening and the lack of local data on domestic reagents in the elderly population, this study aimed to evaluate the diagnostic performance and clinical applicability of domestic interferon-gamma release assay （IGRA） reagents for LTBI screening in the community-dwelling elderly population, within the implemented “three-tier screening and closed-loop management” pathway in Huangpu District, Shanghai. Methods A retrospective study was conducted based on the data from the TB-free community screening program in Huangpu District. A total of 2019 permanent residents aged ≥42 years were enrolled from April to November 2025 and screened for LTBI using a domestic Biotron IGRA kit. A subset of 278 samples （all positive samples and randomly selected negative samples） was tested head-to-head against the international reference standard QuantiFERON-TB Gold Plus （QFT-Plus） to evaluate concordance. Primary-care adaptability was assessed in the context of the existing screening pathway. Results The overall LTBI positivity rate was 6.3% （128/2019） among the community-dwelling elderly population. Male sex was an independent risk factor for LTBI positivity （adjusted OR = 2.231, 95% CI： 1.53-3.26）. The overall concordance rate between the domestic Biotron IGRA kit and QFT-Plus was 91.4% with a kappa value of 0.83. Sensitivity was 92.2% and specificity was 90.7%. IFN-γ release levels were strongly positively correlated （ρ=0.929, P<0.01）, and discordant samples were concentrated in the critical gray zone of 0.2-0.6 U/mL. The assay can be seamlessly integrated into the existing community-based three-tier screening process and is compatible with the integrated chronic disease management service model. Conclusion The domestic Biotron IGRA kit showed reliable diagnostic performance in the community-dwelling elderly population and has significant cost advantages. It can replace imported reagents for large-scale community-based LTBI screening in low-prevalence areas and support the cost-effective development of TB-free communities.

Key words: latent tuberculosis infection, interferon-gamma release assay, community-based screening, diagnostic performance, TB-free community