Diagnostic accuracy of LAMP versus PCR over the course of SARS-CoV-2 infection

• Main Authors: Masato Inaba, Yuki Higashimoto, Yoko Toyama, Tomoya Horiguchi, Masaya Hibino, Mitsunaga Iwata, Kazuyoshi Imaizumi, Yohei Doi
• Format: Article
• Language: English
• Published: Elsevier 2021-06-01
• Series: International Journal of Infectious Diseases
• Subjects: RT-LAMP; RT-qPCR; Sensitivity; Specificity; COVID-19
• Online Access: http://www.sciencedirect.com/science/article/pii/S1201971221003295

Objective: Reverse transcription loop-mediated isothermal amplification (RT-LAMP) has been validated to diagnose several viral infections. However, its diagnostic accuracy in detecting SARS-CoV-2 in real-life clinical settings remains unclear. This study aimed 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 a positivity of 92.8%, and the sensitivity and specificity compared with RT-qPCR was 100%. However, after the 10th day after onset, the positivity of RT-LAMP decreased to less than 25%, and the 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 findings 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.