The nasopharyngeal swab PCR test has been used as an accurate diagnostic method for COVID-19. However, this method causes patient discomfort and pain during sampling and faces challenges including shortages of healthcare personnel, testing time, and costs. Rapid antigen test kits have been introduced to overcome these issues, but their low sensitivity remains a limitation.

A saliva-based rapid antigen diagnostic test kit developed to overcome these limitations has attracted attention. A team led by Professor Dalsik Kim of the Department of Laboratory Medicine, School of Medicine, Jeonbuk National University (JBNU) developed the kit. According to clinical trial results for the saliva-based rapid antigen diagnostic test kit, the team reported excellent performance with 97.8% sensitivity and 100% specificity in patients within six days of COVID-19 infection.

The research was conducted by a consortium comprising Professor Dalsik Kim's team, Professor Du-woon Kim's team from the Department of Food Engineering at Chonnam National University, and Dr. Yosep Kwon's team from the Korea Basic Science Institute. The consortium developed a gargle containing a specific extract from the sword bean. The sword bean extract in the gargle is an innovative component that effectively detaches coronavirus particles strongly bound to oral cell receptors, enabling collection at high concentrations, and was applied to the rapid antigen diagnostic test kit.

The gargle-based saliva rapid antigen test kit, which demonstrated high sensitivity, can be applied to real-time on-site testing and provides results within five minutes. Therefore, it is expected to be highly useful for self-testing and mass screening.

Professor Dalsik Kim (Department of Laboratory Medicine) said, "Improving the sensitivity of rapid antigen diagnostic test kits, which are highly practical for field use, is very important for COVID-19 diagnosis. This was made possible because the gargle solution used in this clinical trial is able to obtain sufficient amounts of the coronavirus from the oral cavity. Early diagnosis of COVID-19 and the efficiency of public health measures will be greatly improved."

The research results were published online on February 17 in Microbiology Spectrum, the bimonthly scientific journal of the American Society for Microbiology, under the title 'Bean Extract-Based Gargle for Efficient Diagnosis of Active COVID-19 Infection Using Rapid Antigen Tests'.