A TB screening initiative using digital CXR and CAD4TB identified a high TB rate, underscoring the tool’s effectiveness in detecting cases, particularly among asymptomatic individuals. This approach highlights the importance of active case-finding and addressing the challenges in treatment initiation. Learn more about the impact of this innovative screening strategy.

Photo credit: Antonne Santiago // Location: Manila, Philippines// Organisation: Delft Imaging.

From October 2022 to February 2023, TB screening was conducted in the general population for ≥ 15 years with digital Chest X-rays (CXR) and CAD4TB ver. 7. From people with a CAD score of ≥28 or with symptoms screening positive, sputum was collected for GeneXpert MTB/RIF (Xpert). People with CXR suggestive of TB were assessed by a physician. Positive Xpert result was considered bacteriologically confirmed TB (BCTB), and TB diagnosed without bacteriological confirmation was classified as clinically diagnosed TB (CDTB). People with Xpert “trace” results were advised to undergo repeat sputum collection. Patients with CDTB and non-trace Xpert results were referred for TB treatment at the local health centre.

3,116 people participated, and 1,110 (35.6%) had presumptive TB (CAD4TB score of ≥28). 1,096 (99%) eligible participants provided sputum for testing, and 14% (156/1100) had BCTB. 99 (63.5%) BCTB patients were symptom screen negative. Among 156 Xpert results, 51 (32.7%) were trace results. 4% (47/1100) were CDTB.

54% (109/203) of all cases (BCTB and CDTB) initiated TB treatment. Higher rates of treatment initiation were observed among people with BCTB with non-trace Xpert results (81/105, 77%) compared to people with CDTB (28/47, 59%).

Reasons for non-initiation of TB treatment include uncontactable (30/94, 32%), pending health centre initiation (35/94, 37%), repeat test needed (25/94, 27%), refusal to accept the diagnosis (4/94,4%).

TB active case-finding using CAD4TB has identified high rates of TB, and it is a promising approach. Most people with BCTB reported no symptoms. In this setting, trace Xpert results were common, adding a challenge to TB evaluation and treatment. Barriers to treatment initiation require further exploration and action.

REFERENCE: Carnimeo, V. (2023, November 15-18). High-yield active case-finding with computer-aided detection does not always translate into high linkage to care [Conference session]. The Union World Conference on Lung Health 2023, Paris, France.