The availability of simple SARS-CoV-2 detection methods is crucial to contain the COVID-19 pandemic. This study examined whether a commercial LAMP assay can reliably detect SARS-CoV-2 genomes directly in respiratory samples without having to extract nucleic acids (NA) beforehand. Nasopharyngeal swabs (NPS, n = 220) were tested by real-time reverse transcription (RT)-PCR and with the LAMP assay. For RT-PCR, NA were investigated. For LAMP, NA from 26 NPS in viral transport medium (VTM) were tested. The other 194 NPS were analyzed directly without prior NA extraction (140 samples in VTM; 54 dry swab samples stirred in phosphate buffered saline). Ten NPS were tested directly by LAMP using a sous-vide cooking unit. The isothermal assay demonstrated excellent specificity (100%) but moderate sensitivity (68.8%), with a positive predictive value of 1 and a negative predictive value of 0.65 for direct testing of NPS in VTM. The use of dry swabs, even without NA extraction, improved the analytical sensitivity; up to 6% of samples showed signs of inhibition. LAMP could be performed successfully with a sous-vide cooking unit. This technique is very fast, requires little laboratory resources, and can replace rapid antigen tests or verify reactive rapid tests on-site.
【저자키워드】 COVID-19, SARS-CoV-2, RT-PCR, Loop-mediated isothermal amplification, nucleic acids, direct testing, LAMP, 【초록키워드】 COVID-19 pandemic, RT-PCR, Predictive value, Laboratory, nucleic acid, SARS-CoV-2 detection, sensitivity, specificity, Rapid antigen tests, Viral, Positive predictive value, rapid antigen test, Rapid test, VTM, nucleic acids, nasopharyngeal swabs, SARS-CoV-2 genome, LAMP, swabs, reverse transcription, Swab, respiratory, Respiratory samples, moderate, Rapid tests, analytical sensitivity, isothermal, Negative predictive value, transport medium, phosphate, Transport, Viral transport medium, Phosphate Buffered Saline, medium, SARS-CoV-2 genomes, NPs, resources, respiratory sample, reactive, swab sample, tested, analyzed, performed, detect, examined, investigated, in viral, demonstrated, 【제목키워드】 Test, detection, Loop-mediated isothermal amplification, SARS-CoV-2 RNA, Sample,