Advances in tuberculosis diagnostics and biomarkers, 2020-26: scientific evidence, recommendations, gaps, and developmental priorities.

Major advances in tuberculosis diagnostics and biomarker research from 2020 to 2025 have informed updated WHO policy guidance, consolidating recommendations for the detection of tuberculosis disease and drug resistance within a single framework. These recommendations align screening, diagnosis, and drug-resistance testing across populations and specimen types. Digital chest radiography, increasingly supported by computer-aided detection, is now a core WHO-recommended screening and triage tool, improving case detection and referral for confirmatory testing at scale. Decentralised molecular diagnosis has expanded through diversified deployment of WHO-recommended rapid diagnostic test classes, particularly low-complexity automated nucleic acid amplification tests (NAATs), including the Xpert MTB/RIF Ultra and Truenat platforms. These tests are complemented by low-complexity manual NAATs such as tuberculosis loop-mediated isothermal amplification and by emerging near point-of-care molecular platforms under evaluation. Latest WHO policy updates have also introduced a new class of near point-of-care NAATs designed for decentralised use, alongside novel specimen types such as tongue swabs for individuals unable to produce sputum, and programmatic innovations, including sputum pooling, to improve efficiency. Expanded use of molecular diagnostics across non-sputum specimens, including stool, gastric aspirate, and nasopharyngeal samples, together with simplified workflows, has improved bacteriological confirmation in children and other sputum-scarce populations. Rapid molecular drug-resistance testing has advanced with Xpert MTB/XDR, and targeted next-generation sequencing is now recognised as a WHO-endorsed approach for comprehensive drug-susceptibility testing at reference laboratory level. Urine lipoarabinomannan-based assays improve diagnostic yield in people with HIV, particularly those with advanced disease, although performance limitations constrain broader use. Substantial performance, implementation, and equity gaps remain. In parallel, host blood transcriptomic signatures show strong short-term prognostic and triage performance, and additional proteomic, metabolomic, cellular, imaging, and pathogen-derived biomarkers are advancing through clinical evaluation. However, no biomarker has yet met the WHO target product profile criteria for a point-of-care test that reliably distinguishes M tuberculosis infection from tuberculosis disease, including asymptomatic or minimally symptomatic tuberculosis disease, often described in the research literature as subclinical tuberculosis.