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 the World Health Organization (WHO) TB diagnostic standard. Although WHO-recommended molecular rapid diagnostics (mWRDs), including low-complexity automated nucleic acid amplification tests (LCaNAAT), have significantly improved TB detection, high capital, maintenance, and consumable costs have constrained scale-up. Recently, lower-cost, near-point-of-care nucleic acid amplification tests (NPOCs) have emerged offering the potential to expand access to rapid TB diagnosis while reducing the financial burden. To better understand the budget impact of using newer NPOCs as the initial TB diagnostic compared with established mWRDs, we developed a flexible cost calculator. Developed in Microsoft Excel, key parameters were organized 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 available here for free global access. Using two hypothetical countries, 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 56.4% in Scenario 1 (based on current testing trends) and 60.5% in Scenario 2 (based on ambitious testing goals). In hypothetical Country B, the corresponding cost differences were 44.2% in Scenario 1 and 59% in Scenario 2. The analysis showed that countries can reach ambitious TB testing targets over 3 years using NPOCs at roughly the same total cost as implementing one year of current LCaNAAT testing. This highlights the potential of cheaper molecular diagnostics to significantly improve access to mWRDs. By reducing capital and maintenance costs, NPOC platforms let TB programs test and detect more cases within existing budgets, accelerating progress toward universal rapid TB diagnosis.