The Value of Rapid Antigen Tests to Identify Carriers of Viable SARS-CoV-2

Shidlovskaya, Elena V.; Kuznetsova, Nadezhda A.; Divisenko, Elizaveta V.; Nikiforova, Maria A.; Siniavin, Andrei E.; Ogarkova, Daria A.; Shagaev, Aleksandr V.; Semashko, Maria A.; Tkachuk, Artem P.; Burgasova, Olga A.; Gushchin, Vladimir A.

The search for effective methods to detect patients who excrete a viable virus is one of the urgent tasks of modern biomedicine. In the present study, we examined the diagnostic value of two antigen tests BIOCREDIT COVID-19 Ag (RapiGEN Inc., Korea) and SGTI-flex COVID-19 Ag (Sugentech Inc., Korea) for their diagnostic value in identifying patients who excrete viable SARS-CoV-2. As part of the study, we examined samples from 106 patients who had just been admitted to the hospital, who had undergone quantitative RT-PCR and assessment of viability of SARS-CoV-2 using cell culture. Sensitivity was 0.786 (0.492-0.953) for SGTI-flex COVID-19 Ag and 1 (0.768- 1) for Biocredit COVID-19 Ag. Specificity of rapid tests was significantly higher than that of RT-PCR and was 0.663 (0.557-0.758) and 0.674 (0.568-0.768) for SGTI-flex COVID-19 Ag and Biocredit COVID-19 Ag versus 0.304 (0.213-0.409) obtained for PCR. Thus, for tasks of identifying viable SARS-CoV-2 during screening of conditionally healthy people, as well as monitoring those quarantined, rapid tests show significantly better results.