We evaluated the diagnostic accuracy of two newly developed, point-of-care, rapid antigen tests (RATs) for detecting SARS-CoV-2, the AFIAS COVID-19 Ag and the ichroma TM COVID-19 Ag, and investigated antigen kinetics. A total of 200 serially collected nasopharyngeal (NP) specimens from 38 COVID-19 patients and 122 specimens from negative controls were analyzed. Diagnostic sensitivity and specificity were assessed in comparison to molecular test results and subdivided according to targeted genes ( E , RdRP , and N ) and days post-symptom onset (PSO). For the kinetics evaluation, cut-off-indices from serial NP specimens were used according to the number of days PSO. Both RATs showed sensitivity of 91.3‒100% for specimens with cycle threshold (Ct) < 25. The specificity of AFIAS was 98.7‒98.9% and that of ichroma TM was 100.0%. The kappa values of AFIAS and ichroma TM for the molecular testing of specimens with Ct < 25 ( RdRP ) were 0.97 and 1.00, respectively. The sensitivity of AFIAS and ichroma TM for all genes was lower for specimens collected at 8‒14 PSO than for those collected before 7-days PSO. The kinetics profiles showed that antigen levels gradually decreased from ≤ 7-days PSO to > 22-days PSO. Both RATs showed excellent specificity and acceptable sensitivity for NP specimens with higher viral loads and for specimens collected within 7-days PSO. Hence, they have the potential to become useful tools for the early detection of SARS-CoV-2. However, because of concerns about false negativity, RATs should be used in conjunction with molecular tests.
【초록키워드】 SARS-CoV-2, diagnostic, Antigen, point-of-care, sensitivity, specificity, Rapid antigen tests, Diagnostic accuracy, Viral, rapid antigen test, Accuracy, Viral load, cycle threshold, nasopharyngeal, diagnostic sensitivity, Early detection, RdRP, molecular, Molecular tests, PSO, COVID-19 patient, RAT, test results, ( RdRP, profile, negative controls, AFIAS COVID-19 Ag, antigen kinetics, conjunction, false negativity, ichroma TM COVID-19 Ag, kappa values, post-symptom onset, RATs, specimen, molecular test, negative control, analyzed, collected, investigated, evaluated, were used, kappa value, TM COVID-19 Ag, were assessed, 【제목키워드】 COVID-19, SARS-CoV-2 antigen, COVID-19 patient, nasopharyngeal specimen,