Zambia – Detecting more TB cases effectively with CAD4TB
Zambia offers three TB screening algorithms: 1) symptom screening only, 2) triage, and 3) parallel screening. The Ubumi Bwandi (My Health, My Choice) project supported by Stop TB Partnership’s TB REACH Wave 10, aims to increase TB screening and case finding in Copperbelt, the province with significant mining activities.
Dual-site service delivery
Services were provided at a health facility with a container clinic and at a community hub using an ultra-portable X-ray system.
AI-supported X-ray screening
Both sites used chest X-ray with CAD4TB to support TB screening.
Community hub multi-disease screening
The community hub offered TB and multi-disease screening for all individuals.
Strict presumptive TB definition
Presumptive TB was defined using CAD4TB scores of ≥50 and/or TB-related symptoms.
- From July 2023 to July 2024, the health facility detected a higher percentage of presumptive TB cases (13%) than the Community Hub (8%). Of those with MTB detected, 95% had high CAD4TB scores (≥50), and many were clinically diagnosed with TB.
- “Triage” significantly reduced both presumptive cases and tests performed compared to parallel screening, leading to a 30-40% decrease in TB diagnoses and treatments.
- The cascade analysis shows that 45% of individuals with presumptive TB (based on symptoms) but low CAD4TB scores accounted for only 6% of MTB detected, indicating that 94% of MTB cases had high CAD4TB scores (≥50). Additionally, 26% of MTB detected were asymptomatic with high CAD4TB scores.
- The Number Needed to Test (NNT) showed that 39.2 tests were required to find one bac+ TB case among those with low CAD4TB scores, while the NNT was 3.3 for symptomatic individuals with high CAD4TB scores and 6.5 for asymptomatic individuals with high CAD4TB scores.
- The PDX with In challenging circumstances, innovative technologies like AI have become crucial in continuing the fight against TB, especially among key and vulnerable population.presents a valuable opportunity for diagnosing TB in children.
REFERENCE: Schaap, A. et al (2024, November 12-15). Triage or no triage: Use of CXR-CAD in community-wide TB screening in an urban community in Zambia [Presentation]. The Union World Conference on Lung Health, Bali, Indonesia.