Rapid detection of infection is essential for stopping the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The Roche SD Biosensor rapid antigen test for SARS-CoV-2 was evaluated in a nonhospitalized symptomatic population. We rapid-tested a sample onsite and compared results with those from reverse transcription PCR and virus culture. We analyzed date of onset and symptoms using data from a clinical questionnaire.

Overall test sensitivity was 84.9% (95% CI 79.1–89.4) and specificity was 99.5% (95% CI 98.7–99.8). Sensitivity increased to 95.8% (95% CI 90.5–98.2) for persons who sought care within 7 days of symptom onset. Test band intensity and time to result correlated strongly with viral load; thus, strong positive results could be read before the recommended time. Approximately 98% of all viable specimens with cycle threshold <30 were detected. Rapid antigen tests can detect symptomatic sars-cov-2 rapid antigen test nasal instructions infections in the early phase of disease, thereby identifying the most infectious persons.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged >1 year ago but still keeps a strong grip not only on daily life but also on diagnostic capacities.

• Reverse transcription PCR (RT-PCR) has been the standard for diagnosis of acute infection  but has several limitations, such as the requirement for specialized laboratory infrastructure, trained personnel, and reagents that have been in shortage globally .
• In addition, the current turnaround time from sample collection to reporting of the result may take >48 hours (J. van Beek et al., unpub. data,compromising effectiveness of triage, isolation, and contact tracing strategies. Rapid antigen detection tests (Ag RDT) for SARS-CoV-2 appeared on the market in early 2020, but initial reports of poor performance and the lack of independent evaluation results made governments reluctant to invest and consider inclusion into testing algorithms.
• As of February 2021, more than 140 assays are on the market , but relatively few have been extensively validated  V.M. Corman et al., unpub. data.Initial results show that these tests are suitable for detecting early-onset cases with high viral load.
• As expected, the sensitivity of the tests is lower than that of RT-PCR, but in patients in the early phase of illness who have high viral load, performance meets World Health Organization–set criteria of >80% sensitivity and >97% specificity compared with nucleic acid detection methods .
• Thus, these tests could be useful in identifying the most infectious persons (J. van Beek et al.). In an outbreak scenario, diagnostics with lower sensitivity but a faster result can render interventions more effective than standard tests . Implementation of Ag RDT into testing algorithms would enable rapid detection and isolation of new cases and thereby support the test, trace, and isolate strategy with the intent to stop transmission chains and reduce the impact of coronavirus disease (COVID-19).
• In this study, we assessed the performance of the Roche SD Biosensor SARS-CoV-2 rapid antigen test compared with both RT-PCR and virus culture.
• We conducted the field evaluation study at a large public health service testing facility in Rotterdam-Rijnmond, the Netherlands, where most visitors sought care for COVID-19 symptoms.
• Every person >18 years of age who had an appointment for SARS-CoV-2 RT-PCR testing was invited to participate. An additional nasopharyngeal swab specimen was obtained for the Ag RDT in parallel and processed onsite to compare sensitivity and specificity to RT-PCR.
• All samples positive by Ag RDT and PCR were cultured to correlate results with infectivity. The medical research ethics committee of Utrecht decided the study was not subject to the Medical Research Involving Human Subjects Act and did not require full review by an accredited committee (protocol no. 20-606/C).