Optimizing tuberculosis case detection through a novel diagnostic device placement model: the case of Uganda

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• Health Systems Strengthening

Background:

• The Xpert MTB/RIF assay is increasingly adopted in high tuberculosis (TB) burden countries.
• Optimizing the placement of Xpert devices is crucial for maximizing tuberculosis case detection rates (CDR).

Purpose of the Study:

• To compare different strategies for placing Xpert devices within Uganda's health system.
• To determine the optimal placement strategy for maximizing TB case detection and cost-effectiveness.

Main Methods:

• A model-based comparison of five Xpert device placement strategies was conducted using epidemiological and operational data from 139 sites in Uganda.
• Strategies included ranking sites by TB prevalence, smear volume, ART volume, and External Quality Assessment (EQA) performance.
• Two clinical algorithms were compared: Xpert for smear-negative samples versus Xpert replacing smear microscopy.

Main Results:

• Prioritizing sites with higher TB prevalence maximized TB CDR, yielding an incremental rate of 6.2-12.6% compared to microscopy alone.
• The TB Prevalence strategy, particularly when Xpert replaced smear microscopy, resulted in the greatest diagnosis of multidrug-resistant TB (MDR-TB).
• While the Smear Volume strategy had the lowest initial implementation costs, the TB Prevalence strategy offered the lowest cost per additional TB case detected.

Conclusions:

• In Uganda, strategically placing Xpert devices in high TB prevalence settings is the most effective approach for increasing TB CDR and achieving the lowest cost per additional case diagnosed.
• These findings highlight the value of utilizing program-level data to guide the optimal deployment of new diagnostic technologies in resource-limited environments.