Resources to implement general population mobile chest x-ray screening for tuberculosis in Uganda: A trial-based costing analysis

Mobile chest X-ray (CXR) screening interventions are recommended for tuberculosis (TB) screening in high-burden settings, but implementation costs are variable and underreported. Using time-driven activity-based costing, we evaluated the costs of implementing general-population mobile CXR screening in peri-urban Uganda. We conducted a micro-costing analysis of mobile CXR screening using data from an ongoing randomized crossover trial. We adopted a healthcare payer perspective, categorizing costs into equipment, personnel, space, implementation, and consumables. We calculated per-participant costs for each step in the TB screening cascade, as well as total screening and diagnostic costs per positive microbiological result (Xpert Ultra). Sensitivity analyses evaluated the cost implications of varying the screening volume or radiographic risk score thresholds. Among 90,668 age-eligible participants completing CXR screening, 14,630 sputum specimens were collected for Xpert testing (16.1%), including 1,676 from participants who submitted sputum without completing CXR. Overall, 511 participants had valid Xpert-positive results (3.5%), corresponding to 5.6 Xpert-positive results per 1,000 CXRs performed. The estimated cost was $4.41 per person screened and $1,299 per Xpert-positive result (95% uncertainty interval: $1,134-$1,488). Screening and diagnostic costs accounted for 64% and 36% of the cost per Xpert-positive result, respectively. Daily screening volume strongly influenced the cost per positive Xpert result, whereas less stringent X-ray thresholds increased the number of TB cases detected with minimal impact on average cost per positive Xpert. Mobile CXR screening interventions for TB require substantial investment in resources. Program planners can optimize efficiency by targeting high-burden populations, increasing participant volume, and optimizing X-ray risk cutoffs for follow-up diagnostic testing. Our findings highlight the value of context-specific cost data for guiding decisions on scaling up TB screening interventions.