A new class of M. tuberculosis antigen-based skin tests (TBST) have been developed combining the simpler skin-test platform used in tuberculin skin tests (TST) with the specificity of blood-based interferon gamma release assays (IGRAs) that use M. tuberculosis specific antigens. Emerging evidence suggests that compared to IGRA, the tests may have similar specificity and provide more reliable results in children and in HIV-infected cohorts. However, the evidence has not been systematically reviewed.
Objectives
- To assess the available data related to the impact of TBST on patient important outcomes: efficacy of TB preventive treatment (TPT) based on diagnostic tests results, predictive value for progression to TB disease, correlation with exposure gradient, proportion started on TPT.
- To assess the available data on the diagnostic accuracy (sensitivity and specificity) of TB antigen- based skin tests (TBST) for diagnosis of TB infection.
- To assess the available data on the concordance of TBST with TST and IGRAs.
- To conduct a review of the published qualitative data on feasibility, accessibility, equity and end-user values related to TBST implementation.
- To conduct a review of the published economic data on affordability, cost, and cost-effectiveness of TBST implementation.
- To determine questions for future research and issues to be addressed by WHO in subsequent policy recommendations.
WHO will convene a Guideline Development Group (GDG) 9-12 November 2021 in accordance with the WHO processes and procedures for guideline development, to assess the available evidence on the use of afore-mentioned technologies which will be later disseminated as the WHO guidelines.