Screening for tuberculosis in prisons: efficacy of a breath-based diagnostic approach in a high prevalence setting.

BACKGROUND: Tuberculosis (TB) remains a major health threat in prisons, where overcrowding and limited access to care facilitate transmission. We evaluated the diagnostic accuracy and feasibility of the AeoNose for TB screening in Paraguayan prisons. METHODS: In this cross-sectional diagnostic study, people deprived of liberty and prison staff underwent symptom screening, chest X-ray with CAD4TB (v6), and AeoNose breath sampling. Individuals with presumptive TB underwent GeneXpert and mycobacterial culture. Breath signals were analysed using a convolutional neural network. Two subsets were evaluated: all participants with valid samples and the same population excluding prior TB. Five-fold cross-validation was applied. RESULTS: Of 3,752 individuals screened, 2,993 had valid samples. TB prevalence was 6.7%. In subset 1 (188 TB cases) and subset 2 (142 TB cases), mean AUC was 0.634 (SD 0.040) and 0.624 (0.054). Sensitivity and specificity were 0.670 (95% CI 0.592-0.737) and 0.537 (0.518-0.555), and 0.711 (0.630-0.793) and 0.505 (0.491-0.519). CONCLUSIONS: Under real-world prison conditions, AeoNose did not meet WHO criteria for a TB triage test. However, large-scale breath-based screening using portable devices was feasible, supporting further development of non-invasive screening approaches.