TB diagnostic tests: how do we figure out their costs?

Tuberculosis continues to be a major global health problem. Lack of accurate, rapid and cost-effective diagnostic tests poses a huge obstacle to global TB control. While several new diagnostic tools are being developed and evaluated for TB, it is important that new tools are introduced for widespread use only after careful validation of accuracy, impact as well as cost-effectiveness in real-world settings. While there are large numbers of studies on the accuracy of TB diagnostic tests, there are few studies that are focused on cost and cost-effectiveness. There are currently no widely accepted standards on how to evaluate costs of a TB test. In this review, we describe the basic approach for computing the costs of TB diagnostic tests, and provide templates for various data elements and parameters that go into the costing analysis. We hope this will pave the way for a standardized methodology for costing of TB diagnostic tests. Such a tool would enable improved and more generalizable costing analyses that can provide a strong foundation for more sophisticated economic analyses that evaluate the full economic and epidemiological impact resulting from the implementation and routine use of performance-verified new and innovative diagnostic tools. This, in turn, will facilitate evidence-based adoption and use of new diagnostics, especially in resource-limited settings.