Diagnostic accuracy of LAMP versus PCR over the course of SARS-CoV-2 infection. (June 2021)

• Record Type: Journal Article
• Authors: Inaba, Masato; Higashimoto, Yuki; Toyama, Yoko; Horiguchi, Tomoya; Hibino, Masaya; Iwata, Mitsunaga; Imaizumi, Kazuyoshi; Doi, Yohei
• Is Part Of: International journal of infectious diseases. Volume 107(2021)
• Page Start: 195
• Page End: 200
• Publication Date: 2021-06
• Subjects: RT-LAMP -- RT-qPCR -- Sensitivity -- Specificity -- COVID-19; Communicable diseases -- Periodicals; Communicable Diseases -- Periodicals; Communicable diseases; Periodicals; Electronic journals; 616.9
• DOI: 10.1016/j.ijid.2021.04.018
• Languages: English
• ISSNs: 1201-9712

Abstract

Highlights: We compared sensitivities and specificities of the SARS-CoV-2 RT-LAMP with RT-qPCR. Up to the 9th day of onset, RT-LAMP has the same diagnostic sensitivity as RT-qPCR. After the 10th day of onset, the positivity of RT-LAMP decreased considerably. The limit of detection of RT-LAMP was 6.7 SARS-CoV-2 RNA copies/reaction. Abstract: 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.