Digital Chest Radiography Enhances Screening Efficiency for Pulmonary Tuberculosis in Primary Health Clinics in South Africa

Moodley, Nishila, Velen, Kavindhran, Saimen, Amashnee, Zakhura, Noor, Churchyard, Gavin, and Charalambous, Salome (2022) Digital Chest Radiography Enhances Screening Efficiency for Pulmonary Tuberculosis in Primary Health Clinics in South Africa. Clinical Infectious Diseases, 74 (9). pp. 1650-1658.

[img] PDF (Published Version) - Published Version
Restricted to Repository staff only

View at Publisher Website:


Background: Optimized tuberculosis (TB) screening in high burden settings is essential for case finding. We evaluated digital chest X-ray with computer-aided detection (CAD) software (d-CXR) for identifying undiagnosed TB in three primary health clinics in South Africa.

Methods: The cross-sectional study consented adults who were sequentially screened for TB using the World Health Organization (WHO) 4 symptom questionnaire and d-CXR. Participants reporting ≥1 TB symptom and/or CAD score ≥60 (suggestive of TB) provided 2 spot sputum for Xpert MTB/RIF Ultra (Xpert Ultra) and liquid culture testing, respectively. TB yield (proportion of screened tested positive) and number needed to test (NNT; no of tests to identify one TB patient) were calculated. Risk factors for microbiologically confirmed or presumed (on radiological grounds) were determined.

Results: Among 3041 participants, 45% (1356 of 3041) screened positive on either d-CXR or symptoms. TB yield was 2.3% (71 of 3041) using Xpert Ultra and 2.7% (82 of 3041) using Xpert Ultra plus culture. Modelled TB yield (identified by Xpert Ultra) by screening approach was: 1.9% (59 of 3041) for d-CXR alone, 2.0% (62 of 3041) for symptoms alone and 2.3% (71 of 3041) for both. The NNT was 9.7 for d-CXR, 17.8 for symptoms and 19.1 for d-CXR and/or symptom. Males, those with previous TB, untreated HIV or unknown HIV status, and acute illness were at higher risk of developing TB.

Conclusion: d-CXR screening identified a similar yield of undiagnosed TB compared to symptom-based screening, however required fewer diagnostic tests. Due to its objective nature, d-CXR screening may improve case detection in clinics.

Item ID: 72712
Item Type: Article (Research - C1)
ISSN: 1537-6591
Keywords: tuberculosis, screening, digital chest radiography
Copyright Information: © The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail:
Date Deposited: 02 Mar 2022 08:28
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3202 Clinical sciences > 320222 Radiology and organ imaging @ 50%
42 HEALTH SCIENCES > 4202 Epidemiology > 420207 Major global burdens of disease @ 50%
SEO Codes: 20 HEALTH > 2001 Clinical health > 200101 Diagnosis of human diseases and conditions @ 100%
Downloads: Total: 1
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page