In selecting a diagnostic test to implement, it is important to consider the characteristics (i.e. risk factors) of the population being served. These characteristics should be derived from population-based studies, if available, and should include the proportion of:
- TB cases resistant to RIF, INH and FQs;
- People with HIV;
- TB that is extrapulmonary;
- TB among children;
- those with severe illness requiring rapid diagnosis; and
- hospitalized versus ambulatory patients.
Understanding the proportion resistant to a newly introduced drug (e.g. BDQ) is particularly important during the initial stages of using the drug, when treatment capacity may expand more rapidly than DST capacity.