*[1],[2],[3]Eliya, T. T., 1,[4]Ugwu, C., 3Jacob, P., 1Asugu, S., 5Anzaku, A. A., and 1,4,6Bimba, J.
1Zankli Research Centre, Bingham University, Karu, Km 26 Abuja-Keffi Expressway, Karu, Nigeria
2Biological Sciences Department, Bingham University, Karu, Km 26 Abuja-Keffi Expressway, Karu, Nigeria
3Stephakim Life Foundation, No. E7 Debaron Street, Nyanya Phase 4, Abuja, Nigeria
4Clinical Sciences, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, United Kingdom
5Institute of Human Virology, Nigeria. Plot 62, Emeritus Umaru Shehu Cadastral Zane COO, Abuja FCT, Nigeria
6Community Medicine, Bingham University, Karu, Km 26 Abuja-Keffi Expressway, Karu, Nigeria *Correspondence to: iliya.taryuta@binghamuni.edu.ng
Abstract:
Background: Tuberculosis (TB) is one of the leading causes of death worldwide, with an estimated 1.25 million people dying from TB in 2023. Most current diagnostic tests for TB rely on sputum sampling from symptomatic individuals. Sputum collection procedure involves expectoration of potentially infectious aerosols, which pose safety risks to health care workers; hence, an easier, safer, non-invasive, non-aerosol, and more effective alternative approach is warranted. This study evaluated the effectiveness and diagnostic yield of self-collected oral swab (SCOS) against sputum in detecting Mycobacterium tuberculosis (MTB) by Xpert MTB/RIF assay.
Methodology: A cross-sectional comparative design was used in evaluating SC-OS against sputum for early diagnosis of TB in adolescents and adults with presumed TB in Karu Local Government Area, Nasarawa State, Nigeria. Two samples, comprising early morning SC-OS, and one sputum sample were collected from each consented participant. SC-OS and sputum were transported immediately to the laboratory at room temperature and cold chain, respectively. The Xpert MTB/RIF Ultra assay was performed on both specimens, and the graph of the cycle threshold values was plotted for both samples. The sensitivity, specificity, and predictive values of SC-OS were calculated, with sputum as the ‘gold standard’ sample.
Results: Of the 419 participants, 266 (63.5%) were males, and 12 (2.8%) were ≤ 14 years. Thirty-six (8.6%) were positive, with 2 (5.6%) rifampicin resistant. When compared to sputum Xpert MTB as the ‘gold standard’, the sensitivity and specificity of the SC-OS Xpert MTB were 97.2% and 99.7%, respectively.
Conclusion: The self-collected oral swab showed high sensitivity and specificity with the sputum sample, and is potentially easier, safer, non-invasive, non-aerosol, and effective in detecting TB by Xpert/MTB. Although further research is warranted, our findings show that SC-OS can serve as an alternative sample for early detection of M. tuberculosis.
Keywords: Self-collected oral swab, Sputum, Xpert MTB, Diagnostic performance
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