In 2017, tuberculosis caused an estimated 1·6 million deaths, including 300 000 deaths among people with HIV, and surpassed HIV/AIDS to become the leading infectious cause of mortality worldwide. Approximately 36% of tuberculosis cases each year (around 3·5 million cases) are not diagnosed or reported, which might have contributed to the increase in tuberculosis prevalence. Current diagnostic tools in routine clinical use, including the GeneXpert MTB/RIF assay (Cepheid, Sunnyvale, CA, USA), rely on sputum-based testing, which has consistently demonstrated suboptimal diagnostic sensitivity, especially in immunocompromised people with HIV who are unable to produce sputum when admitted to hospital or at increased risk of extrapulmonary disease. Research and development of new tuberculosis diagnostics has been lagging behind knowledge of tuberculosis pathogenesis, which includes incipient and subclinical tuberculosis. As a result, WHO has prioritised a biomarker-based non-sputum test that could be used at the clinical point of care to rapidly diagnose all forms of tuberculosis (including extrapulmonary tuberculosis) for individuals of all ages, including children.