OBJECTIVE: Reverse transcription loop-mediated isothermal amplification (RT-LAMP) has been validated for diagnosis of several viral infections . However, its diagnostic accuracy in detecting SARS-CoV-2 in real-life clinical settings remains unclear . The aim of this study was to determine the diagnostic sensitivity and specificity of RT-LAMP compared to reverse transcription-quantitative polymerase chain reaction (RT-qPCR) over the disease course of COVID-19 .
METHODS: A total of 124 nasopharyngeal swab samples obtained from 24 COVID-19 patients were tested by RT-LAMP and RT-qPCR . Sensitivities and specificities of RT-LAMP compared with RT-qPCR were analyzed as a function of time from onset .
RESULTS: Up to the 9th day after onset, the RT-LAMP had positivity of 92.8%, and the sensitivity and specificity compared with RT-qPCR was 100% . After the 10th day of onset, however, the positivity of RT-LAMP decreased to less than 25%, and concordance of positivity between the two methods was below 60% . The limit of detection of RT-LAMP was 6.7 copies/reaction .
CONCLUSIONS: Until the 9th day after the onset of symptoms, RT-LAMP had the same diagnostic accuracy as RT-qPCR . These finding suggest that RT-LAMP can be used as a diagnostic tool for COVID-19 as an alternative to RT-qPCR in the acute symptomatic phase of COVID-19.