Clinical validation of quantitative SARS-CoV-2 antigen assays to estimate SARS-CoV-2 viral loads in nasopharyngeal swabs. Issue 4 (April 2021)

• Record Type: Journal Article
• Authors: Aoki, Kotaro; Nagasawa, Tatsuya; Ishii, Yoshikazu; Yagi, Shintaro; Okuma, Sadatsugu; Kashiwagi, Katsuhito; Maeda, Tadashi; Miyazaki, Taito; Yoshizawa, Sadako; Tateda, Kazuhiro
• Is Part Of: Journal of infection and chemotherapy. Volume 27:Issue 4(2021)
• Page Start: 613
• Page End: 616
• Publication Date: 2021-04
• Subjects: Covid-19 -- SARS-CoV-2 -- Nasopharynx -- Nasopharyngeal swab -- Saliva -- Chemiluminescent enzyme immunoassay -- Sensitive quantitative antigen test; Chemotherapy -- Periodicals; Infection -- Periodicals; Communicable diseases -- Chemotherapy -- Periodicals; 615.5805
• DOI: 10.1016/j.jiac.2020.11.021
• Languages: English
• ISSNs: 1341-321X

Abstract

Abstract: Background: Expansion of the testing capacity for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important issue to mitigate the pandemic of coronavirus disease-2019 (COVID-19) caused by this virus. Recently, a sensitive quantitative antigen test (SQT), Lumipulse® SARS-CoV-2 Ag, was developed. It is a fully automated chemiluminescent enzyme immunoassay system for SARS-CoV-2. Methods: In this study, the analytical performance of SQT was examined using clinical specimens from nasopharyngeal swabs using reverse transcription polymerase chain reaction (RT-PCR) as a control. Results: Receiver operating characteristic analysis of 24 SARS-CoV-2-positive and 524 -negative patients showed an area under the curve of 0.957 ± 0.063. Using a cut-off value of 1.34 pg/ml, the sensitivity was 91.7%, the specificity was 98.5%, and the overall rate of agreement was 98.2%. In the distribution of negative cases, the 99.5 percentile value was 1.03 pg/ml. There was a high correlation between the viral load calculated using the cycle threshold value of RT-PCR and the concentration of antigen. The tendency for the antigen concentration to decrease with time after disease onset correlated with that of the viral load. Conclusions: Presented results indicate that SQT is highly concordant with RT-PCR and should be useful for the diagnosis of COVID-19 in any clinical setting. Therefore, this fully automated kit will contribute to the expansion of the testing capability for SARS-CoV-2.