An at-home and electro-free COVID-19 rapid test based on colorimetric RT-LAMP

Purpose: In the fight against virus-caused pandemics like COVID-19, the use of diagnostic tests based on RT-qPCR is essential but sometimes limited by their dependence on expensive, specialized equipment and skilled personnel. Consequently, an alternative nucleic acid detection technique that gets over these restrictions, called loop-mediated isothermal amplification following reverse transcription (RT-LAMP), has been broadly investigated. Nevertheless, the developed RT-LAMP assays for SARS-CoV-2 detection still require laboratory devices and are electrically dependent, limiting their widespread use as rapid home tests. In this work, a flexible RT-LAMP assay that gets beyond the drawbacks of the available isothermal LAMP-based SARS-CoV-2 detection was developed, establishing a simple and effective at-home diagnosis tool for COVID-19. Methods: A multiplex direct RT-LAMP assay modified from the previously developed test was applied to simultaneously identify the two genes of SARS-CoV-2. We used a colorimetric readout, lyophilized reagents, and benchmarked an electro-free and micropipette-free method that enables sensitive and specific detection of SARS-CoV-2 in home settings. Results: Forty-one nasopharyngeal swab samples were tested using the home-testing RT-LAMP (HT-LAMP) assay developed, showing 100% agreement with the RT-qPCR results. Conclusions: This is the first electrically independent RT-LAMP assay successfully developed for SARS-CoV-2 detection at home setting. Our HT-LAMP assay is thus an important development for diagnosing COVID-19 or any other infectious pandemic on a population scale.