Hidden in Plain Sight: How Portable Digital X-Ray Reveals Asymptomatic TB Cases Missed by Routine Screening in Nigeria
1
KNCV Nigeria, Abuja, Nigeria
Popul. Med. 2026;8(Supplement Supplement 1):
ABSTRACT
INTRODUCTION:
Symptom-based TB screening remains the standard approach across Nigeria, but it consistently fails to detect subclinical or asymptomatic TB, contributing to ongoing community transmission. Portable Digital X-ray (PDX) integrated with Computer-Aided Detection (CAD) offers an innovative solution for identifying TB among individuals who would otherwise remain undiagnosed. Context and Aim This study assesses how PDX with CAD (≥40 threshold) deployed by KNCV in collaboration with the NTBLCP enhanced TB case detection among people with no cough or any clinical signs, particularly in hard-to-reach and security-challenged communities.
METHODS:
We conducted a retrospective analysis of community screening data (January 2025–December 202) from LGAs across 7 Nigerian states implementing . A total of 32,480 individuals were screened using PDX. All persons with CAD ≥40 underwent sputum collection for GeneXpert testing. Data were analyzed for positivity patterns, age/sex distributions, number of cases missed by symptom screening, and PDX efficiency ratios.
RESULTS:
Of 32,480 screened, 19,762 (60.9%) reported no TB symptoms. Among these asymptomatic individuals, 6,411 (32.4%) had CAD scores ≥40. GeneXpert testing yielded 713 bacteriologically confirmed TB cases, translating to an overall TB positivity of 11.1% among asymptomatic high-CAD individuals. Comparative analysis shows that if screening relied solely on symptoms, 100% of these 713 cases would have been missed. This represents a 3.5-fold increase in case detection compared to routine symptom screening. Demographically: - 69% (493) of asymptomatic positives were males. - The age group 25–44 years contributed 52% of cases. -PDX efficiency analysis shows that 7 asymptomatic people with CAD ≥40 needed to be screened to find one TB case (NNS=7). Innovative Contribution This study provides strong evidence that PDX + CAD screening identifies a substantial reservoir of silent TB infections. Integrating PDX into community programs can dramatically reduce missed cases, interrupt transmission, strengthen health security,and accelerate Nigeria’s progress toward TB elimination.
Symptom-based TB screening remains the standard approach across Nigeria, but it consistently fails to detect subclinical or asymptomatic TB, contributing to ongoing community transmission. Portable Digital X-ray (PDX) integrated with Computer-Aided Detection (CAD) offers an innovative solution for identifying TB among individuals who would otherwise remain undiagnosed. Context and Aim This study assesses how PDX with CAD (≥40 threshold) deployed by KNCV in collaboration with the NTBLCP enhanced TB case detection among people with no cough or any clinical signs, particularly in hard-to-reach and security-challenged communities.
METHODS:
We conducted a retrospective analysis of community screening data (January 2025–December 202) from LGAs across 7 Nigerian states implementing . A total of 32,480 individuals were screened using PDX. All persons with CAD ≥40 underwent sputum collection for GeneXpert testing. Data were analyzed for positivity patterns, age/sex distributions, number of cases missed by symptom screening, and PDX efficiency ratios.
RESULTS:
Of 32,480 screened, 19,762 (60.9%) reported no TB symptoms. Among these asymptomatic individuals, 6,411 (32.4%) had CAD scores ≥40. GeneXpert testing yielded 713 bacteriologically confirmed TB cases, translating to an overall TB positivity of 11.1% among asymptomatic high-CAD individuals. Comparative analysis shows that if screening relied solely on symptoms, 100% of these 713 cases would have been missed. This represents a 3.5-fold increase in case detection compared to routine symptom screening. Demographically: - 69% (493) of asymptomatic positives were males. - The age group 25–44 years contributed 52% of cases. -PDX efficiency analysis shows that 7 asymptomatic people with CAD ≥40 needed to be screened to find one TB case (NNS=7). Innovative Contribution This study provides strong evidence that PDX + CAD screening identifies a substantial reservoir of silent TB infections. Integrating PDX into community programs can dramatically reduce missed cases, interrupt transmission, strengthen health security,and accelerate Nigeria’s progress toward TB elimination.
| eISSN: | 2654-1459 |
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