Self-Sampled Gargle Water Direct RT-LAMP as a Screening Method for the Detection of SARS-CoV-2 Infections
Skaiste Arbaciauskaite,
Pouya Babakhani,
Natalia Sandetskaya,
Dalius Vitkus,
Ligita Jancoriene,
Dovile Karosiene,
Dovile Karciauskaite,
Birute Zablockiene,
Dirk Kuhlmeier
Affiliations
Skaiste Arbaciauskaite
Department of Diagnostics, Fraunhofer Institute for Cell Therapy and Immunology IZI, Perlickstraße 1, 04103 Leipzig, Germany
Pouya Babakhani
Department of Computer Science, University of Bath, Claverton Down, Bath BA2 7AY, UK
Natalia Sandetskaya
Department of Diagnostics, Fraunhofer Institute for Cell Therapy and Immunology IZI, Perlickstraße 1, 04103 Leipzig, Germany
Dalius Vitkus
Institute of Biomedical Sciences, Vilnius University Faculty of Medicine, M.K. Ciurlionio 21, LT-03101 Vilnius, Lithuania
Ligita Jancoriene
Clinic of Infectious Diseases and Dermatovenerology, Institute of Clinical Medicine, Vilnius University Faculty of Medicine, M.K. Ciurlionio 21, LT-03101 Vilnius, Lithuania
Dovile Karosiene
Centre of Laboratory Medicine, Vilnius University Hospital Santaros Klinikos, Santariskiu 14, LT-08406 Vilnius, Lithuania
Dovile Karciauskaite
Institute of Biomedical Sciences, Vilnius University Faculty of Medicine, M.K. Ciurlionio 21, LT-03101 Vilnius, Lithuania
Birute Zablockiene
Clinic of Infectious Diseases and Dermatovenerology, Institute of Clinical Medicine, Vilnius University Faculty of Medicine, M.K. Ciurlionio 21, LT-03101 Vilnius, Lithuania
Dirk Kuhlmeier
Department of Diagnostics, Fraunhofer Institute for Cell Therapy and Immunology IZI, Perlickstraße 1, 04103 Leipzig, Germany
We assessed the viability of self-sampled gargle water direct RT-LAMP (LAMP) for detecting SARS-CoV-2 infections by estimating its sensitivity with respect to the gold standard indirect RT-PCR of paired oro-nasopharyngeal swab samples. We also assessed the impact of symptom onset to test time (STT)—i.e., symptom days at sampling, on LAMP. In addition, we appraised the viability of gargle water self-sampling versus oro-nasopharyngeal swab sampling, by comparing paired indirect RT-PCR results. 202 oro-nasopharyngeal swab and paired self-sampled gargle water samples were collected from hospital patients with COVID-19 associated symptoms. LAMP, indirect and direct RT-PCR were performed on all gargle water samples, and indirect RT-PCR was performed on all oro-nasopharyngeal samples. LAMP presented a sensitivity of 80.8% (95% CI: 70.8–90.8%) for sample pairs with sub-25 Ct oro-nasopharyngeal indirect RT-PCR results, and 77.6% (66.2–89.1%) sensitivity for sub-30 Ct samples with STT ≤ 7 days. STT, independently of Ct value, correlated negatively with LAMP performance. 80.7% agreement was observed between gargle water and oro-nasopharyngeal indirect RT-PCR results. In conclusion, LAMP presents an acceptable sensitivity for low Ct and low STT samples. Gargle water may be considered as a viable sampling method, and LAMP as a screening method, especially for symptomatic persons with low STT values.
