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

Yuto Takeuchi,Yusaku Akashi,Daisuke Kato,Miwa Kuwahara,Shino Muramatsu,Atsuo Ueda,Shigeyuki Notake,Koji Nakamura,Hiroichi Ishikawa,Hiromichi Suzuki

doi:10.1016/j.jiac.2021.02.029

Yuto Takeuchi, Yusaku Akashi + Show 8 more

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https://doi.org/10.1016/j.jiac.2021.02.029

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IntroductionSeveral 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. MethodsThis 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. ResultsA 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%). ConclusionQuickNavi™-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.

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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
Additional samples for antigen test were collected from patients who have been referred from a local public health center and 89 primary care facilities (Supplementary Table 1) and healthcare workers of Tsukuba Medical Center Hospital (TMCH), and their clinical information was obtained after receiving the subjects’ informed consent
Of the 2079 referred patients and 45 healthcare workers, a total of 1208 individuals who had nasopharyngeal samples collected for antigen test and had provided their informed consent were initially included

Summary

Introduction

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. Using the results of real-time RT-PCR as a reference, the performance of the antigen test was evaluated. Results: A total of 1186 patients were included in this study, and the real-time RT-PCR detected SARSCoV-2 in 105 (8.9%). Of these 105 patients, 33 (31.4%) were asymptomatic. Conclusion: QuickNaviTM-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. More accessible point-ofcare tests and take a shorter time to produce results; they can be more useful in limited-resource settings, provided they reliably detect SARS-CoV-2.

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