An online, open-access, cost comparison tool for presumptive tuberculosis testing using low complexity, automated, nucleic acid amplification tests (LCaNAAT) versus near point-of-care (NPOCs) molecular tests

The world is far from achieving universal access to rapid tuberculosis (TB) diagnostics that align with World Health Organization (WHO) diagnostic standards. Although WHO-recommended molecular rapid diagnostics (mWRDs), including low-complexity automated nucleic acid amplification tests (LCaNAAT), have significantly improved TB detection, scale-up has been constrained by high capital, maintenance, and consumable costs. Recently, lower-cost, near-point-of-care nucleic acid amplification tests (NPOCs) have emerged, with attractive global-access pricing, offering the potential to expand access to rapid TB diagnosis while reducing the financial burden. To support TB program staff better understand the budget impact of using newer NPOCs as the initial TB diagnostic compared with established mWRDs, we developed a flexible cost calculator. Originally built in Microsoft Excel for Mac (version 16.91, build 24111020), it organizes key parameters in a structured input sheet using standardized labels. Separate worksheets defined diagnostic scenarios and performed calculations, with results summarized in an overview covering various costs. After validation, the model was converted into R (version 2025.09.1 + 401). The app (app.R), developed with Shiny, is now available here for free global access. Using two hypothetical country case studies, we compared current LCaNAAT- based testing strategies with scenarios in which NPOCs were implemented as the initial diagnostic test. In hypothetical Country A, there were cost savings of 43% in Scenario 1 (based on current testing trend) and 38% in Scenario 2 (based on ambitious testing goals). In hypothetical Country B, the corresponding cost differences were 55% in Scenario 1 and 40. 5% in Scenario 2. The analysis showed that countries can reach ambitious TB testing targets using NPOCs at roughly the same cost as current LCaNAAT testing. This highlights the potential of affordable molecular diagnostics to improve access to mWRDs. By reducing capital and maintenance costs, NPOCs allow TB programs to test and detect more cases within existing or slightly increased budgets, speeding up progress toward universal rapid TB diagnosis.