Diagnostic accuracy of a novel SARS-CoV-2 antigen-detecting rapid diagnostic test from standardized self-collected anterior nasal swabs

AbstractBackgroundAntigen-detecting rapid diagnostic tests (Ag-RDT) for SARS-CoV-2 offer new opportunities for the quick and laboratory-independent identification of infected individuals for control of the SARS-CoV-2 pandemic. Despite the potential benefits, nasopharyngeal sample collection is frequently perceived as uncomfortable by patients and requires trained healthcare personnel with protective equipment. Therefore, anterior nasal self-sampling is increasingly recognized as a valuable alternative.MethodsWe performed a prospective, single-center, point of care validation of an Ag-RDT using a polypropylene absorbent collector for standardized self-collected anterior nasal swabs. Real-Time Polymerase Chain Reaction (RT-PCR) from combined oropharyngeal/nasopharyngeal swabs served as a comparator. Primary endpoint was sensitivity of the standardized Ag-RDT in symptomatic patients with medium or high viral concentration (≥ 1 million RNA copies on RT-PCR for SARS-CoV-2).ResultsBetween February 12 and March 22, 2021, 388 participants were enrolled. After exclusion of 9 patients for which no PCR result could be obtained, the novel Ag-RDT was evaluated based on 379 participants, of which 273 were symptomatic and 106 asymptomatic. In 61 samples from symptomatic patients with medium or high viral load (≥ 1 million RNA copies), the sensitivity of the standardized Ag-RDT was 96.7% (59/61; 95%CI: 88.7-99.6%) for the primary endpoint. In total, 62 positive Ag-RDT results were detected out of 70 RT-PCR positive individuals, yielding an overall sensitivity of 88.6% (95%CI: 78.7-94.9%). Specificity was 99.7% (95%CI: 98.2-100%) in 309 RT-PCR negative individuals.ConclusionHere, we present a validation of a novel Ag-RDT with a standardized sampling process for anterior nasal self-collection, which meets WHO criteria of ≥80% sensitivity and ≥97% specificity. Although less sensitive than RT-PCR, this assay could be beneficial due to its rapid results, ease of use, and suitability for standardized self-testing.(Funded by Drägerwerk AG & Co. KGaA, Lübeck, Germany; ClinicalTrials.gov number NCT04698993)