The evaluation of a newly developed antigen test (QuickNavi™-COVID19 Ag) for SARS-CoV-2: A prospective observational study in Japan

• Published in: Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy Vol. 27; no. 6; pp. 890 - 894
• Main Authors: Takeuchi, Yuto, Akashi, Yusaku, Kato, Daisuke, Kuwahara, Miwa, Muramatsu, Shino, Ueda, Atsuo, Notake, Shigeyuki, Nakamura, Koji, Ishikawa, Hiroichi, Suzuki, Hiromichi
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01.06.2021; Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd
• Subjects: Adolescent; Adult; Aged; Antigen test; Antigens, Viral - isolation & purification; COVID-19; COVID-19 - diagnosis; COVID-19 Testing - methods; Female; Humans; Immunochromatography; Japan; Male; Middle Aged; QuickNavi™-COVID19 Ag; SARS-CoV-2; Sensitivity and Specificity; Young Adult; Japan; COVID-19; Antigen test; SARS-CoV-2; QuickNavi™-COVID19 Ag; Immunochromatography
• ISSN: 1341-321X; 1437-7780; 1437-7780
• DOI: 10.1016/j.jiac.2021.02.029

Several antigen tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been developed worldwide, but their clinical utility has not been well established. In this study, we evaluated the analytical and clinical performance of QuickNavi™-COVID19 Ag, a newly developed antigen test in Japan. This prospective observational study was conducted at a PCR center between October 7 and December 5, 2020. The included patients were referred from a local public health center and 89 primary care facilities. We simultaneously obtained two nasopharyngeal samples with flocked swabs; one was used for the antigen test and the other for real-time reverse transcription PCR (RT-PCR). Using the results of real-time RT-PCR as a reference, the performance of the antigen test was evaluated. A total of 1186 patients were included in this study, and the real-time RT-PCR detected SARS-CoV-2 in 105 (8.9%). Of these 105 patients, 33 (31.4%) were asymptomatic. The antigen test provided a 98.8% (95% confidence interval [CI]: 98.0%–99.4%) concordance rate with real-time RT-PCR, along with a sensitivity of 86.7% (95% CI: 78.6%–92.5%) and a specificity of 100% (95% CI: 99.7%–100%). False-negatives were observed in 14 patients, 8 of whom were asymptomatic and had a low viral load (cycle threshold (Ct) > 30). In symptomatic patients, the sensitivity was 91.7% (95% CI: 82.7%–96.9%). QuickNavi™-COVID19 Ag showed high specificity and sufficient sensitivity for the detection of SARS-CoV-2. This test is a promising potential diagnostic modality especially in symptomatic patients.