Assessment of the clinical and analytical performance of the Aptima SARS-CoV-2 assay using the VALCOR protocol

Abstract

BackgroundThe COVID-19 pandemic highlighted the importance of diagnostic testing against curbing the spread of SARS-CoV-2. The urgent need and scale for diagnostic tools resulted in manufacturers of SARS-CoV-2 assays receiving emergency authorization that lacked robust analytical or clinical evaluation. As it is highly likely that testing for SARS-CoV-2 will continue to play a central role in public health, the performance characteristics of assays should be evaluated to ensure reliable diagnostic outcomes are achieved.MethodsVALCOR or “VALidation of SARS-CORona Virus-2 assays” is a study protocol designed to set up a framework for test validation of SARS-CoV-2 virus assays. Using clinical samples collated from VALCOR, the performance of Aptima SARS-CoV-2 assay was assessed against a standard comparator assay. Diagnostic test parameters such as sensitivity, specificity and overall per cent agreement were calculated for the clinical performance of Aptima SARS-CoV-2 assay.ResultsA total of 180 clinical samples were tested with an addition of 40 diluted clinical specimens to determine the limit of detection. When compared to the standard comparator assay Aptima had a sensitivity of 100.0% [95% CI 95.9–100.0] and specificity of 96.7% [95% CI 90.8–99.3]. The overall percent agreement was 98.3% with an excellent Cohen’s coefficient of κ = 0.967 [95% CI 0.929–1.000]. For the limit of detection, Aptima was able to detect all of the diluted clinical samples.ConclusionIn conclusion. validation of Aptima SARS-CoV-2 assay using clinical samples collated through the VALCOR protocol showed excellent test performance. Additionally, Aptima demonstrated high analytical sensitivity by detecting all diluted clinical samples corresponding to a low limit of detection.