Abstract
National Tuberculosis Reference Laboratories (NTRLs) are central to tuberculosis (TB) control programs. Between 2018 and 2024, the Republic of Congo, a country of 6 million inhabitants, achieved a transformative strengthening of its TB diagnostic system, coordinated by the NTRL. Strategic investments, supported mainly by international partners, enabled a substantial decentralization of services, expanding the diagnostic network from 38 to 113 diagnostic and testing centers and increasing GeneXpert sites from 3 to 31. The expansion of the diagnostic network and specimen referral system was associated with a reduced structural gap in diagnostic coverage by extending access to GeneXpert testing to a larger number of peripheral and previously underserved centers. Critically, the establishment of a BSL-3 laboratory and the deployment of advanced assays like Xpert MTB/XDR ended the reliance on overseas testing by introducing in-country capacity for multidrug-resistant and pre-extensively drug-resistant TB detection. These systemic improvements were associated with significant positive outcomes, including an annual molecular testing surging from 11,609 in 2022 to over 27,000 in 2024 and bacteriological confirmation rates rising from 34 to 73%. This comprehensive laboratory systems strengthening, which also facilitated cross-programmatic initiatives like HIV and Mpox testing integration, underscores how sustained investment in infrastructure, logistics, and quality management is fundamental to improving case detection, surveillance, and progress toward the WHO End TB Strategy milestones.