1. New Manual Quantitative Polymerase Chain Reaction Assay Validated on Tongue Swabs Collected and Processed in Uganda Shows Sensitivity That Rivals Sputum-based Molecular Tuberculosis Diagnostics
- Author
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Steadman, Amy, Andama, Alfred, Ball, Alexey, Mukwatamundu, Job, Khimani, Khushboo, Mochizuki, Tessa, Asege, Lucy, Bukirwa, Alice, Kato, John Baptist, Katumba, David, Kisakye, Esther, Mangeni, Wilson, Mwebe, Sandra, Nakaye, Martha, Nassuna, Irene, Nyawere, Justine, Nakaweesa, Annet, Cook, Catherine, Phillips, Patrick, Nalugwa, Talemwa, Bachman, Christine M, Semitala, Fred Collins, Weigl, Bernhard H, Connelly, John, Worodria, William, and Cattamanchi, Adithya
- Subjects
Biomedical and Clinical Sciences ,Clinical Sciences ,Clinical Research ,Tuberculosis ,Rare Diseases ,Infectious Diseases ,Emerging Infectious Diseases ,HIV/AIDS ,Vaccine Related ,4.2 Evaluation of markers and technologies ,Detection ,screening and diagnosis ,Infection ,Good Health and Well Being ,Humans ,Female ,Sputum ,Male ,Uganda ,Adult ,Tongue ,Sensitivity and Specificity ,Specimen Handling ,Mycobacterium tuberculosis ,Real-Time Polymerase Chain Reaction ,Molecular Diagnostic Techniques ,Middle Aged ,Young Adult ,Tuberculosis ,Pulmonary ,tuberculosis ,diagnosis ,nonsputum ,tongue swab ,oral swab ,Biological Sciences ,Medical and Health Sciences ,Microbiology ,Clinical sciences - Abstract
BackgroundSputum-based testing is a barrier to increasing access to molecular diagnostics for tuberculosis (TB). Many people with TB are unable to produce sputum, and sputum processing increases assay complexity and cost. Tongue swabs are emerging as an alternative to sputum, but performance limits are uncertain.MethodsFrom June 2022 to July 2023, we enrolled 397 consecutive adults with cough >2 weeks at 2 health centers in Kampala, Uganda. We collected demographic and clinical information, sputum for TB testing (Xpert MTB/RIF Ultra and 2 liquid cultures), and tongue swabs for same-day quantitative polymerase chain reaction (qPCR) testing. We evaluated tongue swab qPCR diagnostic accuracy versus sputum TB test results, quantified TB targets per swab, assessed the impact of serial swabbing, and compared 2 swab types (Copan FLOQSWAB and Steripack spun polyester).ResultsAmong 397 participants, 43.1% were female, median age was 33 years, 23.5% were diagnosed with human immunodeficiency virus, and 32.0% had confirmed TB. Sputum Xpert Ultra and tongue swab qPCR results were concordant for 98.2% (95% confidence interval [CI]: 96.2-99.1) of participants. Tongue swab qPCR sensitivity was 92.6% (95% CI: 86.5 to 96.0) and specificity was 99.1% (95% CI: 96.9 to 99.8) versus microbiological reference standard. A single tongue swab recovered a 7-log range of TB copies, with a decreasing recovery trend among 4 serial swabs. Swab types performed equivalently.ConclusionsTongue swabs are a promising alternative to sputum for molecular diagnosis of TB, with sensitivity approaching sputum-based molecular tests. Our results provide valuable insights for developing successful tongue swab-based TB diagnostics.
- Published
- 2024