An assessment of molecular diagnosis of tuberculosis and multi-drug resistant tuberculosis testing and quality assessment: findings of an international survey

Molecular ‘in vitro diagnostic’ (IVD) tests are established for the diagnosis of tuberculosis (TB) and multi-drug resistant TB (MDR-TB). What is less clear is how the use of TB or MDR-TB molecular IVD results differ across regions, whether corroborative tests are conducted and what external quality assessment (EQA) infrastructure exists to underpin test confidence. This study investigated the current international status of molecular TB IVDs methods, application and quality assessment. An online survey was distributed by the IFCC’s Committee for molecular diagnostics to TB diagnostic laboratories worldwide. 118 laboratories from 41 nations indicated a range of IVDs were used. ∼75 % participated in EQA programs and 32 % reported this used the WHO International Standard. ∼65 % also delivered MDR-TB results the majority of which were used to change therapy; 1/6 of these do so without EQA evaluation of the MDR-TB result. The study demonstrates a range of IVD solutions in use for TB diagnosis along with a high uptake of EQA in support of this global uptake of this test modality. However, we also reveal gaps in quality assurance for MDR-TB testing with 10 % of the laboratories using resistant results alone without participating MDR-TB EQA. This suggest additional work is required to build on established use of EQA to better support MDR-TB testing and better ensure confident when results are used to guide antibiotic use. Addressing these gaps will ensure the accuracy of future MDR-TB results, which is critical for effective disease management and help combat TB on a global scale.