Saliva-based COVID-19 Rapid Antigen Test: a practical and accurate alternative mass screening method

ABSTRACT As SARS-CoV-2 and its variants continue to spread, a reliable and convenient alternative to nasopharyngeal swabbing and RT-PCR testing is needed. To test the usability and performance of saliva sample collection, saliva, nasal and nasopharyngeal swab specimens were collected from a total of 338 individuals consisting of confirmed COVID-19 patients and healthy subjects. To evaluate the diagnostic accuracy of self-collected and performed SARS-CoV-2 rapid antigen test on saliva and nasal swabs specimens, we compared its performance to nasopharyngeal swab specimen RT-PCR as a comparator test. In saliva specimens, the positive percent agreement was 90.14%, and the negative percent agreement was 99.61%, while in nasal swab specimens, the positive percent agreement was 91.55%, and the negative percent agreement was 100%, both meeting the sensitivity and specificity criteria required by the FDA. Therefore, when considering both the reliability and convenience of testing, we found saliva testing to be the better method for large-scale and frequent self-testing.