Accuracy of the tuberculosis molecular bacterial load assay to diagnose and monitor response to anti-tuberculosis therapy: a longitudinal comparative study with standard-of-care smear microscopy, Xpert MTB/RIF Ultra, and culture in Uganda

A longitudinal prospective study evaluating the accuracy of tuberculosis molecular bacterial load assay (TB-MBLA) for diagnosis and monitoring treatment response compared to standard-of-care tests. The study enrolled 210 participants with presumptive tuberculosis at China-Uganda Friendship Hospital Naguru in Kampala, Uganda, between November 2019 and June 2022. Results showed TB-MBLA and Xpert MTB/RIF Ultra had similar diagnostic sensitivities (99%) but TB-MBLA had higher specificity (90% vs 78%). TB-MBLA demonstrated superior performance in monitoring treatment response, with conversion to negative occurring 3.3 times faster than Xpert-Ultra, taking 13 weeks versus 52 weeks respectively to reach complete tuberculosis negativity.