Case Study

Timor-Leste – National TB prevalence survey and asymptomatic TB detection with Delft Light and CAD4TB

Delft Light in Timor Leste

A national TB prevalence survey was conducted from 2020 to 2023 to determine the burden of TB, including subclinical TB cases.

National TB prevalence survey

A nationally representative random cluster survey was conducted among adults aged 15 years and older.

Symptom screening and X-ray

Participants underwent symptom screening and chest X-ray using Delft Light ultra-portable X-rays with CAD4TB.

AI-based triage threshold

A CAD4TB score of 60 or higher was used to identify presumptive TB cases.

Confirmatory testing pathway

Participants with abnormal X-rays or TB symptoms received GeneXpert testing, with liquid culture performed for Xpert-positive cases.

Result

Out of 15,267 participants,

7 .4%
were symptom screen positive
4 .4%
were CXR/CAD4TB screen positive
  • Among those with high CAD4TB scores, 36% had no TB symptoms. This resulted in 22% of bacteriologically confirmed TB cases being subclinical.
  • A total of 162 participants were confirmed with Bac+ TB. Notably, 22% of Bac+ TB cases would have been missed without using Chest X-rays with CAD4TB.
Delft Light in Timor Leste
Conclusion
  • The survey revealed a substantial burden of subclinical TB in Timor-Leste.
  • These findings underscore the importance of active case finding and the use of CXRs to enhance the sensitivity of TB screening algorithms.

REFERENCE: Atok, l. et al (2024, November 12-16). Sub-clinical TB in participants of a national prevalence survey in Timor-Leste [Presentation]. The Union World Conference on Lung Health, Bali, Indonesia.