Author:
Fang Rixun,Coleman Sha,Kwok Claudina,Heisser Helena,Wang Teresa,Kim Lynn J.,Coopersmith Ali,Crawford Darren,Ha Kimberly,Gaiteri Joseph C.,(Johnson) Chiang Yuh-Min
Abstract
ABSTRACTBACKGROUNDThe pandemic of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has had a profound global impact on human health and the economy. Early diagnosis and prompt effective treatment can reduce disease spread. At present, the majority of high-accuracy diagnostic tests for COVID-19 are conducted in specialized laboratories and rely on conventional quantitative real-time polymerase chain reaction (PCR) techniques. This diagnostic approach presents several challenges, including prolonged turnaround times and high costs due to the time and technical skills required to administer test protocols. Our primary aim is to develop a diagnostic platform suitable for use entirely within the point-of-care setting, avoiding the time and resource requirements of standard PCR test processing conducted away from the point-of-care.METHODS AND FINDINGSWe developed the Alveo be.well COVID-19 Test as a diagnostic tool for qualitative detection of SARS-CoV-2 RNA in upper respiratory specimens. This innovative test detects viral RNA from SARS-CoV-2 within an unprocessed nasal specimen through the application of reverse transcription-loop mediated isothermal amplification (RT-LAMP) and electrical impedance measurement. The LAMP test primers are specifically designed to amplify a conserved region in the nucleocapsid gene of SARS-CoV-2 RNA, ensuring detection accuracy. To enhance usability and shelf life at ambient temperature, the primers are embedded within a microfluidic cartridge, along with other required reagents for viral target amplification. This test is designed for point-of-care settings, offering a straightforward and user-friendly process. The test includes: nasal swab sample collection; elution of the sample in a buffer; transfer of the eluted sample into the cartridge; insertion of the cartridge into an analyzer for amplification, and real-time result interpretation. All processing steps, including heating, mixing, amplification, and detection, occur within the cartridge during the test run, making it particularly user-friendly and obviating the need for significant user training. Results are displayed on a mobile smart device within approximately 50 minutes, via the be.well app, facilitating real-time decision-making in the point-of-care environment. Test and result data is also transferred to and stored in the cloud.To evaluate the analytical performance of this platform, we initially assessed the analytical sensitivity and specificity of the Alveo be.well COVID-19 test. We also evaluated the diagnostic performance of the Alveo be.well COVID-19 assay using contrived reference samples. Furthermore, we validated the clinical performance of the Alveo be.well COVID-19 test in different clinical settings in both USA and United Kingdom during the pandemic seasons in 2020 through 2022. Test results from 253 nasal swab samples were compared to a real-time reverse transcription polymerase chain reaction (RT-PCR) reference standard.CONCLUSIONSThe development of the Alveo be.well platform for infectious disease testing, including SARS-CoV-2 diagnosis, represents a significant advancement in portable diagnostic technology, encompassing both nucleic acid amplification and detection technologies. In testing SARS-CoV-2, the system amplifies the nucleic acid target within unprocessed nasal specimens using RT-LAMP chemistry, while concurrently measuring the electrical impedance signal produced during target amplification process, delivering results in under an hour. The system exhibits high analytical specificity and sensitivity, with a limit of detection of as low as 4000 viral genomic copies per milliliter, making it highly effective for detecting the SARS-CoV-2 target. Results derived from clinical validation studies showed 93% sensitivity and 95% specificity when compared to RT-qPCR. This system was demonstrated to be a user-friendly and rapid diagnostic platform with high analytical and clinical specificity and sensitivity for SARS-CoV-2 detection with the potential to facilitate early, fast diagnosis of SARS-CoV-2 to help contain the spread of the disease, particularly in point-of-care settings.
Publisher
Cold Spring Harbor Laboratory