Fig. 1.

Comparison of the results between the SARS-CoV-2 antigen (Ag) test and RT-qPCR.

(A) A total of 313 nasopharyngeal samples were subjected to RT-qPCR (58 positive and 255 negative). The same samples were also subjected to the Ag test. The beeswarm plot shows the SARS-CoV-2 Ag levels in the RT-qPCR-positive (light blue) and -negative samples (red).

(B) Receiver operating characteristic (ROC) curve analysis. The Ag test achieved an area under the ROC curve (AUC) value of 0.848 ± 0.044.

(C) Comparison of data obtained with the Ag test and RT-qPCR. An overall agreement of 91.4% was achieved between the two tests, with 55.2% sensitivity and 99.6% specificity obtained with the Ag test.