Comparison of performance between three SARS-CoV-2 molecular assays (Aptima™, Laboratory Developed Test-Fusion, and R-GENE®) with special attention to turnaround time, a key point in laboratory management.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) highlights the importance of rapid diagnostic testing to identify individuals with SARS-CoV-2 infections and to limit the spread of the virus. Many molecular assays have become commercially available to cope with this surging demand for timely diagnosis of COVID-19 cases, but identifying individuals requires accurate diagnostic tools. We compared the performance of three molecular SARS-CoV-2 assays: Aptima™ SARS-CoV-2 assay running on the Panther system (Hologic), an in-house assay (Laboratory Developed Test, LDT) running on the Fusion module of the Panther Fusion system (LDT-Fusion; Hologic), and the R-GENE® SARS-CoV-2 assay (bioMérieux). In addition, we also evaluated the turnaround time. This parameter is crucial to managing the SARS-CoV-2 diagnosis and represents a key point in the quality management at the laboratory. Aptima™ and LDT-Fusion assays exhibited an excellent positive percent agreement (PPA) (100.0%), while the R-GENE® assay showed a slightly decreased PPA (98.2%). The Hologic assays have a higher throughput with less hands-on time than the R-GENE® assays (24-25 vs. 71 min). Both Hologic assays are used on a fully automated random-access testing system with on-demand testing capabilities that avoid run series, unlike the R-GENE® assay. Automated random-access testing systems should be preferred during periods of high SARS-CoV-2 prevalence.

What is the true place of the SARS-CoV-2 rapid point-of-care antigen test in the hospital setting? Lessons learned from real life.

To assist in the clinical management of patients and to support infection control, we tested the use of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) point-of-care antigen test (AgPOC) for unplanned hospitalization, coupled with a nucleic acid amplification test (NAAT) using specimens collected at the same time upon arrival. The aim of this study was to assess the performance of the AgPOC in this specific use compared to NAAT for SARS-CoV-2 diagnosis, in the context of the low prevalence of infection. For 5 months (between two peaks in France of the SARS-CoV-2 pandemic), all patients admitted who undertook the AgPOC/NAAT paired tests were included in the study. AgPOC performances were determined considering the clinical status and the delay of symptoms onset. NAAT and AgPOC results were available for 4425 subjects. AgPOC results showed a homogeneous specificity (>97%) but a low sensitivity at 45.8%. Considering the national guidelines, sensitivity dropped to 32.5% in cases of symptomatic patients with symptoms older than 5 days or more. This study shows the poor performance of AgPOC for entry screening of patients in hospitals. AgPOC may represent a useful tool in the hospital setting only if the use is restricted to patients with consistent symptoms less than 4 days old.