Accuracy of the Mologic COVID-19 rapid antigen test: a prospective multi-centre analytical and clinical evaluation

Background: The coronavirus disease 2019 (COVID-19) pandemic has highlighted the reliance on antigen detection rapid diagnostic tests (Ag-RDTs). Their evaluation at point of use is a priority. Methods: Here, we report a multi-centre evaluation of the analytical sensitivity, specificity, and clinical accuracy of the Mologic COVID-19 Ag-RDT by comparing to reverse transcriptase polymerase chain reaction (RT-qPCR) results from individuals with and without COVID-19 symptoms. Participants had attended hospitals in Merseyside, hospital and ambulance services in Yorkshire, and drive-through testing facilities in Northumberland, UK. Results: The limit of detection of the Mologic COVID-19 Ag-RDT was 5.0 x 10 2 pfu/ml in swab matrix with no cross-reactivity and interference for any other pathogens tested. A total of 347 participants were enrolled from 26 th of November 2020 to 15 th of February 2021 with 39.2% (CI 34.0-44.6) testing RT-qPCR positive for SARS-CoV-2. The overall sensitivity and specificity of the Mologic Ag-RDT compared to the reference SARS-CoV-2 RT-qPCR were 85.0% (95% CI 78.3-90.2) and 97.8% (95.0-99.3), respectively. Sensitivity was stratified by RT-qPCR cycle threshold (Ct) and 98.4% (91.3-100) of samples with a Ct less than 20 and 93.2% (86.5-97.2) of samples with a Ct less than 25 were detected using the Ag-RDT. Clinical accuracy was stratified by sampling strategy, swab type and clinical presentation. Mologic COVID-19 Ag-RDT demonstrated highest sensitivity with nose/throat swabs compared with throat or nose swabs alone; however, the differences were not statistically significant. Conclusions: Overall, the Mologic test had high diagnostic accuracy across multiple different settings, different demographics, and on self-collected swab specimens. These findings suggest the Mologic rapid antigen test may be deployed effectively across a range of use settings.