Comparing the Effectiveness of Colorimetric Reverse Transcription-Loop-Mediated Isothermal Amplification (SCoV-2 Detection Kit L1) with that of Reverse Transcription-Quantitative Polymerase Chain Reaction in SARS-CoV-2 Detection

Objective: To determine the diagnostic sensitivity and specificity of reverse transcription-loop-mediated isothermal amplification (RT-LAMP) compared to those of reverse transcription-quantitative polymerase chain reaction (RT-qPCR) for coronavirus disease 2019 (COVID-19).Material and Methods: A total of 382 nasopharyngeal swab samples obtained from 154 patients with COVID-19 were tested using RT-LAMP and RT-qPCR. The sensitivities and specificities of RT-LAMP were compared with those of RT-qPCR and analysed as a function of time from onset. Results: Up to the third day after onset, the RT-LAMP SARS-CoV-2 positivity was 68.33%, and the sensitivity and specificity compared to those of RT-qPCR were 100.0%. However, on the third day after onset, the RT-LAMP SARS-CoV-2 positivity decreased to less than 50%. The limit of detection for the RT-LAMP assay was log10 SARS-CoV-2 RNA 2.2 copies/reaction. RT-LAMP had the same diagnostic accuracy as RT-qPCR until day 9 after symptom onset.Conclusion: The findings suggest that RT-LAMP can be used as an alternative to RT-qPCR as a diagnostic tool for detecting COVID-19 during the acute symptomatic phase of COVID-19.