Technology Challenges and Opportunities Across the Cascade of TB Care
PHC facilities serve an essential role across the cascade of TB care. They face multiple challenges, however, to fully implement national and WHO TB control guidelines. New technologies and improvements to existing ones are needed to address these challenges and create new opportunities to stop the spread of TB and drug resistance. Missed diagnosis is currently the most critical gap to fill, with tools and equipment needed that can be effectively used for care at the PHC level. Innovations across the cascade of TB care can enhance early detection and ensure timely, effective treatment to stop the spread of TB. A web-based atlas of innovations is in development to showcase new approaches for TB elimination at varying stages from discovery to deployment and for an audience including health officials, policy makers, researchers and funders.
Diagnosis
TB diagnosis in high-burden countries is done through microscopy, molecular testing using different biomarkers, or chest X-ray. Most PHC facilities send out samples for diagnostic testing at higher-level facilities or central laboratories. This delays diagnosis and causes loss to follow-up. New TB diagnostic tools are needed that are sensitive and specific, applicable broadly across patients, affordable and easy to use, and readily accessible at the PHC level. These benefits vary depending on the combination of test type and sample type. For instance, TB diagnostic tests based on bacterial nucleic acids are highly sensitive even in immunocompromised patients and are specific to active TB cases rather than cases of TB exposure or latent TB. This contrasts with the IGRA and tuberculin tests, based respectively on host and bacterial proteins, that are used for initial screening and require a confirmatory diagnostic test.
The Covid-19 pandemic showed what is possible for diagnostics. India, for instance, had a striking increase in the number of laboratories capable of molecular diagnostic testing. This presents an opportunity to build on locally driven momentum and more comprehensively develop molecular diagnostic testing for the PHC level, integrating it across diseases and health conditions for mutual benefit. The TB diagnostics Pipeline Report 2024 is an annually updated outline of the pipeline of innovative tools for tuberculosis diagnosis and detection of drug resistance.