Clinical performance of SARS-CoV-2 antigen-detection rapid diagnostic test using SERS-based lateral flow immunoassay

Background: 'ACROSIS COVID-19 Ag (NPS)' kit (SG Medical, Seoul, Korea) is a newly developed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigen-detection rapid diagnostic test (Ag-RDT) using surface-enhanced Raman scattering (SERS)-based lateral flow immunoassay (LFIA). We evaluated its clinical performance compared with STANDARD Q COVID-19 Ag (SD Biosensor, Suwon, Korea), a previously approved Ag-RDT.Methods: A total of 286 nasopharyngeal swab specimens were collected: 104 positive and 182 negative specimens in SARS-CoV-2 real-time reverse-transcription polymerase-chain-reaction (rRT-PCR). SARS-CoV-2-positive specimens were divided according to the cycle threshold (Ct) value in rRT-PCR. The clinical performance of ACROSIS was compared with that of STANDARD Q.Results: ACROSIS showed significantly higher sensitivity than STANDARD Q (92.3% vs. 85.6%, P = 0.02), especially in specimens with 25 = Ct < 30 (78.6% vs. 42.9%). The Ct values of RdRp/S genes for 95% detection rates by ACROSIS and STANDARD Q were 25.8 and 23.0, respectively.Conclusions: This is the first study that evaluated the performance of ACROSIS compared with STANDARD Q. The overall clinical performance of ACROSIS was superior to that of STANDARD Q, especially in specimens with 25 = Ct < 30. ACROSIS could be useful for SARS-CoV-2 Ag detection even in relatively low viral load specimens.