The impact and cost of using mobile digital X-ray units to detect pulmonary TB in South Africa.

BACKGROUND: Digital chest X-ray (dCXR) enables early TB detection where symptoms screening is inadequate. We evaluated the impact and cost of three dCXR delivery models: long-term community-based mobile vans (LT-vans), long-term facility-based containers (LT-containers), and short-term community-based mobile vans (ST-vans), implemented by a non-governmental organisation (NGO) across two South African provinces. METHODS: Between 2020 and 2022, nine dCXR units were deployed in four high-TB-burden districts for 1-19 months. Screening yield and TB test positivity were collected from electronic databases. Costs were estimated from the provider perspective using micro-costing methods, with both economic and financial costs reported for NGO-led and routine care implementation. RESULTS: Overall, 34,110 individuals were screened, 8,605 (25.2%) had abnormal dCXR results, and 1,372 TB cases were diagnosed (4.0% positivity). The cost per person screened with dCXR ranged from $39 to $240. LT-vans had the highest TB positivity (10.1%), followed by LT-containers (3.7%) and ST-vans (1.7%). The lowest cost per TB case identified was with LT-vans ($384 economic; $375 financial) under routine care implementation, and the highest with ST-vans ($14,157 economic; $8,741 financial) under NGO-led implementation. CONCLUSION: Long-term mobile vans were the most cost-effective model, yielding the highest TB rates, while short-term vans offered high volumes but at higher costs.