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TURN-TB (Trace Ultra Result iNsight in TB screening) is a case-control study that aims to compare baseline Xpert® MTB/RIF Ultra (“Ultra”) assay "trace-positive" individuals to positive and negative controls and includes a longitudinal cohort study with TB-negative controls. Partly in coordination with the STOMP-TB study, the study conducts community-based TB screening as well as recruitment from local facilities, and enrolls participants with trace-positive results for an extensive baseline clinical and laboratory evaluation. Those who are not diagnosed with TB at baseline are closely followed for up to 2 years to evaluate the incidence of TB, treat it promptly if it develops, and observe any changes that occur over time in symptoms, microbiological results, imaging findings, and host responses. The study’s primary aims are to:  

  1. Characterize baseline evidence for current or past TB disease and infection among individuals with Ultra-trace-positive sputum.

  2. Longitudinally evaluate the incidence of TB and the dynamics of molecular, imaging, and immunological findings among individuals with trace-positive Ultra but no active TB at study entry.

  3. Quantitatively and qualitatively explore the implications of trace-positive results and associated patient trajectories for active TB case finding strategies.


This study will clarify the current burden and future risk of TB in people with Ultra-trace-positive sputum, while gaining insight into the dynamics that underlie trace-positive Ultra results. The study will also use individual- and population-level modeling and a public health ethics analysis to place what we learn from Ultra-trace-positive individuals into public health and policy context for more effective TB case-finding. The study started enrollment in 2021 and recently completed its first 2-year follow up in January of 2023.

For more information, see our publications page


TURN-TB Team Members

Principal Investigators: Emily Kendall, Achilles Katamba

Co-Investigators: David Dowdy, Moses Joloba, Petros Karakousis, Maria Merritt

Coordinators: Mariam Nantale, Patrick Biché

Lab Coordinator: Caleb Kamoga

Data Manager: Annet Nalutaaya

Research Assistants: David Isooba, James Mukiibi, Olga Nakasolya

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