ABSTRACT The antigen-based rapid diagnostic test (Ag-RDT) using saliva specimens is fast, noninvasive, and suitable for SARS-CoV-2 self-testing, unlike nasopharyngeal swab (NPS) testing. We evaluated a novel Beanguard gargle (BG)-based virus collection method that can be applied to Ag-RDT as an alternative to the current RT-PCR with an NPS for early diagnosis of COVID-19. This clinical trial comprised 102 COVID-19-positive patients hospitalized after a governmental screening process and 100 healthy individuals. Paired NPS and BG-based saliva specimens from COVID-19 patients and healthy individuals were analyzed using NPS-RT-PCR, BG-RT-PCR, and BG-Ag-RDTs, whose diagnostic performance for detecting SARS-CoV-2 was compared. BG-Ag-RDTs showed high sensitivity (97.8%) and specificity (100%) in 45 patients within 6 days of illness and detected all cases of SARS-CoV-2 Alpha and Delta variants. In 11 asymptomatic active COVID-19 cases, both BG-Ag-RDTs and BG-RT-PCR showed sensitivities and specificities of 100%. Sensitivities of BG-Ag-RDT and BG-RT-PCR toward salivary viral detection were highly concordant, with no discrimination between symptomatic (97.0%), asymptomatic (100%), or SARS-CoV-2 variant (100%) cases. The intermolecular interactions between SARS-CoV-2 spike proteins and truncated canavalin, an active ingredient from the bean extract (BE), were observed in terms of physicochemical properties. The detachment of the SARS-CoV-2 receptor-binding domain from hACE2 increased as the BE concentration increased, allowing the release of the virus from hACE2 for early diagnosis. Using BG-based saliva specimens remarkably enhances the Ag-RDT diagnostic performance as an alternative to NPS and enables noninvasive, rapid, and accurate COVID-19 self-testing and mass screening, supporting efficient COVID-19 management. IMPORTANCE An Ag-RDT is less likely to be accepted as an initial test method for early diagnosis owing to its low sensitivity. However, our self-collection method, Ag-RDT using BG-based saliva specimens, showed significantly enhanced detection sensitivity and specificity toward SARS-CoV-2 including the Alpha and Delta variants in all patients tested within 6 days of illness. The method represents an attractive alternative to nasopharyngeal swabs for the early diagnosis of symptomatic and asymptomatic COVID-19 cases. The evidence suggests that the method could have a potential for mass screening and monitoring of COVID-19 cases.
【저자키워드】 COVID-19, SARS-CoV-2, sensitivity, specificity, Rapid diagnostic test, oral virus, 【초록키워드】 clinical trial, diagnostic test, SARS-CoV-2 variant, diagnostic, Delta, delta variant, RT-PCR, virus, variants, hACE2, Antigen, Nasopharyngeal swab, early diagnosis, Viral, Mass screening, Asymptomatic, Rapid diagnostic test, nasopharyngeal swabs, symptomatic, management, SARS-CoV-2 spike protein, Patient, Alpha, Viral detection, ingredient, Ag-RDT, COVID-19 patients, Delta variants, Evidence, Detection sensitivity, Concentration, Spike proteins, RDTs, COVID-19 cases, Physicochemical properties, COVID-19 patient, noninvasive, alternative, healthy individuals, domain, Ag-RDTs, SARS-CoV-2 spike proteins, alpha and delta variants, sensitivities, intermolecular interactions, Specificities, screening process, saliva specimens, Detachment, canavalin, NPs, salivary, ENhance, initial, tested, analyzed, significantly, evaluated, less, healthy individual, intermolecular interaction, patients hospitalized, saliva specimen, symptomatic and asymptomatic, the SARS-CoV-2, 【제목키워드】 Test, Rapid, gargle, efficient, Bean,