COVID-19: Rapid Antigen detection for SARS-CoV-2 by lateral flow 1 assay: a national systematic evaluation for mass-testing

Background: New lateral flow device (LFD) viral antigen immunoassays have been developed by commercial and research organisations around the world as diagnostic tests for SARS-CoV-2 infection. To support decisions by the UK Government on potential scale-up of mass population testing, we have at their request evaluated the 35 diagnostic performance of a significant number of point-of-care rapid SARS-CoV-2 LFDs. Methods : 132 LFDs were initially reviewed by a Department of Health and Social Care team, part of the UK government, from which 64 were selected for further evaluation. Standardised laboratory evaluations, and for 39 those that met the published criteria, field testing in the Falcon-C19 research study and UK pilots were performed (UK COVID-19 testing centres, hospital, schools, armed forces). Results : 4/64 LFDs so far have desirable performance characteristics from independent laboratory studies and early preliminary field evaluations (Orient Gene, Deepblue and Innova SARS-CoV-2 Antigen Rapid Qualitative Test ), of which one underwent extended clinical assessment in field studies ( Innova ). 8951 Innova LFD tests were performed with a kit failure rate of 5.6% (502/8951, 95% CI: 5.1-6.1), false positive rate of 0.32% (22/6954, 45 95% CI: 0.20-0.48) and a viral antigen detection/sensitivity (using RNA RT-PCR as a proxy for the presence of 46 antigen) of 78.8% when performed by laboratory scientists (156/198, 95% CI 72.4-84.3). Sensitivity was significantly lower when testing was undertaken by non-experts with limited initial training Interpretation : Several LFDs have promising performance characteristics for mass population testing and can be used to identify infectious positive individuals. The Innova LFD shows good viral antigen detection/sensitivity with excellent specificity, although kit failure rates and the impact of training are potential issues. These results support the expanded evaluation of LFDs, and assessment of greater access to testing on COVID-19 transmission. LFDs are observed in 10-30 minutes depending on the device, providing a window for early interventions to halt the chain of transmission earlier in the disease course when individuals are most infectious. 12 we report the diagnostic performance of first-generation SARS-CoV-2 antigen-detecting LFD for rapid point-of-care (POC) testing in work that was commissioned on our national evaluation of SARS-CoV-2 viral antigen-detecting LFDs, focussing on the Innova Qualitative a viral antigen detection (sensitivity) 78.8% RT-PCR standard’ for positive negative our evaluation, test largely maintained different settings cohorts; operator-dependent kit infrequent. in phase 3b, which involved testing by laboratory personnel or trained healthcare professionals. To identify patients with higher viral loads (Ct<25), LFD had >90% sensitivity. Sensitivity was lower in phase 4 evaluations, while specificity was maintained. The simplicity of LFDs, requirement for specialist training or equipment, that they are an attractive option for testing. Future research should focus on post-implementation evaluation of diagnostic accuracy, including the potential benefit of regular serial sampling to improve accuracy and reduce transmission.