Analytical performance of the rapid qualitative antigen kit for the detection of SARS-CoV-2 during widespread circulation of the Omicron variant. Issue 3 (March 2023)

• Record Type: Journal Article
• Authors: Suzuki, Hiromichi; Akashi, Yusaku; Kato, Daisuke; Takeuchi, Yuto; Kiyasu, Yoshihiko; Terada, Norihiko; Kurihara, Yoko; Kuwahara, Miwa; Muramatsu, Shino; Ueda, Atsuo; Notake, Shigeyuki; Nakamura, Koji
• Is Part Of: Journal of infection and chemotherapy. Volume 29:Issue 3(2023)
• Page Start: 257
• Page End: 262
• Publication Date: 2023-03
• Subjects: Nasopharyngeal sample -- SARS-CoV-2 -- COVID-19 -- Omicron variant -- QuickNavi-COVID19 Ag; Chemotherapy -- Periodicals; Infection -- Periodicals; Communicable diseases -- Chemotherapy -- Periodicals; 615.5805
• DOI: 10.1016/j.jiac.2022.11.006
• Languages: English
• ISSNs: 1341-321X

Abstract

Abstract: Introduction: Rapid qualitative antigen testing is essential in the clinical management of COVID-19. However, most evaluations of antigen tests have been performed before the emergence of the Omicron variant. Methods: This prospective observational study evaluated QuickNavi-COVID19 Ag, a rapid antigen detection test between December 2021 and February 2022 in Japan, using real-time reverse transcription (RT)-PCR as a reference. Two nasopharyngeal samples were simultaneously collected for antigen testing and for RT-PCR. Variant analysis of the SARS-CoV-2 genomic sequencing was also performed. Results: In total, nasopharyngeal samples were collected from 1073 participants (417 positive; 919 symptomatic; 154 asymptomatic) for analysis. Compared with those of RT-PCR, the sensitivity, specificity, positive predictive value, and negative predictive value were 94.2% (95% CI: 91.6%–96.3%), 99.5% (95% CI: 98.7%–99.9%), 99.2% (95% CI: 97.8%–99.8%), and 96.5% (95% CI: 94.8%–97.7%), respectively. The sensitivity among symptomatic individuals was 94.3% (95% CI: 91.5%–96.4%). Overall, 85.9% of sequences were classified as Omicron sublineage BA.1, 12.4% were Omicron sublineage BA.2, and 1.6% were Delta B.1.617.2. (Delta variant). Most of the samples (87.1%) had Ct values of <25, and the sensitivity was 47.4% for low viral load samples (Ct ≥ 30); a similar trend has been observed in both symptomatic and asymptomatic groups. Conclusions: The QuickNavi-COVID19 Ag test showed sufficient diagnostic performance for the detection of the SARS-CoV-2 Omicron sublineages BA.1 and BA.2 from nasopharyngeal samples. However, the current study was mainly performed in symptomatic patients and the results are not sufficiently applicable for asymptomatic patients.