Prospective analytical performance evaluation of the QuickNavi™-COVID19 Ag for asymptomatic individuals

Abstract

Introduction: Antigen testing may help screen for and detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in asymptomatic individuals. However, limited data regarding the diagnostic performance of antigen tests for this group are available. Methods: We used clinical samples to prospectively evaluate the analytical and clinical performance of the antigen test QuickNavi™-COVID19 Ag. This study was conducted at a PCR center between October 7, 2020 and January 9, 2021. Two nasopharyngeal samples per patient were obtained with flocked swabs; one was used for the antigen test, and the other for real-time reverse transcription PCR (RT-PCR). The diagnostic performance of the antigen test was compared between asymptomatic and symptomatic patients, and the RT-PCR results were used as a reference. Results: Among the 1934 collected samples, 188 (9.7%) demonstrated detection of SARS-CoV-2 by real-time RT-PCR; 76 (40.4%) of these 188 samples were from asymptomatic individuals, and over half of the total samples were asymptomatic (1073; 55.5%). The sensitivity of the antigen test was significantly lower for the asymptomatic group than for symptomatic patients (67.1% vs. 89.3%, respectively, p < 0.001). The specificity was 100% for both groups, and no false positives were observed among all 1934 samples. The median cycle threshold value for the asymptomatic group was significantly higher than that of the symptomatic group (24 vs. 20, p < 0.001). Conclusions: The QuickNavi™-COVID19 Ag showed lower sensitivity for the asymptomatic group than for symptomatic patients. However, its specificity was consistently high, and no false positives were found in this study.

Diagnostic accuracy of rapid point-of-care tests for diagnosis of current SARS-CoV-2 infections in children: a systematic review and meta-analysis

“… **Not explicitly stated, but as per inclusion criteria only study participants who are asymptomatic. ††The study reported by Kiyasu et al 54 is specified as ‘extension study’ of a previous study reported by Takeuchi et al . 50 Both studies were included in this systematic review and considered as two separate studies due to different but overlapping recruitment periods, substantial differences in the proportion of paediatric study participants who were symptomatic and differences in how discordant RT-PCR test results were re-evaluated.…”

Evaluation and clinical implications of the time to a positive results of antigen testing for SARS-CoV-2

“…The reactivity of antigen tests can differ between clinical and UTM™ samples. QuickNavi™-COVID19 Ag detected the virus in almost all clinical samples with Ct values <30 when the supplied extraction reagent was used [ 7 , 18 ], but the sensitivity plummeted when samples were diluted in UTM™ [ 19 ]. Measuring the limit of detection seems insufficient to verify the clinical performance of antigen tests.…”

Clinical evaluation of the rapid nucleic acid amplification point-of-care test (Smart Gene SARS-CoV-2) in the analysis of nasopharyngeal and anterior nasal samples

“…In this study, we enrolled participants and collected samples at the PCR center in Tsukuba Medical Center Hospital (TMCH) between March 25 and July 5, 2021, which intensively collected nasopharyngeal samples for the PCR analysis of SARS-CoV-2 [ [5] , [6] , [7] , [8] , [9] ]. Subjects referred by 59 primary care facilities and a local public health center, as well as TMCH healthcare workers with suspected SARS-CoV-2 infection based on symptoms or a known contact history with COVID-19 confirmed/suspected patients were prospectively enrolled.…”