Affordable Access

Publisher Website

Evaluation of the Elecsys SARS-CoV-2 antigen assay for the detection of SARS-CoV-2 in nasopharyngeal swabs.

  • Ben Abdelhanin, Myriam1
  • Mvumbi, Dieudonné M2
  • Agathine, Aurélie3
  • Nanos, Nikolaos4
  • Gidenne, Stéphane5
  • 1 Department of Clinical Chemistry, LBS Laboratory, Cerba HealthCare, Brussels, Belgium. Electronic address: [email protected] , (Belgium)
  • 2 Department of Expertise and Service provision, Quality of Laboratories, Sciensano, Brussels, Belgium. , (Belgium)
  • 3 Department of Clinical Microbiology, LBS Laboratory, Cerba HealthCare, Brussels, Belgium. , (Belgium)
  • 4 Department of Clinical Serology, LBS Laboratory, Cerba HealthCare, Brussels, Belgium. , (Belgium)
  • 5 Department of Clinical Microbiology, Ketterthill Laboratory, Cerba HealthCare, Belvaux, Luxembourg. , (Luxembourg)
Published Article
Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology
Publication Date
Oct 01, 2021
DOI: 10.1016/j.jcv.2021.104991
PMID: 34626880


The aim of this study was to evaluate the performance of the automated Elecsys® SARS-CoV-2 antigen assay compared to RT-PCR taken as the gold standard for SARS-CoV-2 detection. 225 nasopharyngeal swabs were randomly collected among which 123 were tested positive and 102 negatives for SARS-CoV-2 based on RT-PCR. Antigen dosing were performed on a Cobas 8000 e801 analyzer. The antigen test diagnosed SARS-CoV-2 infection status with an overall sensitivity of 65,85% (95% CI 56,76-74,16%), a specificity of 100% (95% CI 96,49-100%) with a Cut-off value ≥ 1. When the cut-off value for the antigen assay was set to > 0,673 COI, the accuracy reached its highest level with a sensitivity of 74,8% (95% CI 66,2 - 82,2%) and a specificity of 97,1% (95% CI 91,6 - 99,4%). Imprecision was estimated in accordance with manufacturer's claims. We obtained an overall sensitivity of 65,85% (95% CI 56,76-74,16%) and a specificity of 100% (95% CI 96,49-100%), slightly higher than the results reported by the manufacturer. Yet, it remains relatively low comparatively to what is generally acceptable for these antigenic assays (a relative sensitivity of 80%). We also noticed that the accuracy could reach its highest level if the cut-off is set above 0,673 which is lower than established by the manufacturer. Thus, our results suggest that the Elecsys® SARS-CoV-2 Antigen assays, should be improved prior to be used in a SARS-Cov-2 screening strategy. However, if one antigenic assay could demonstrate acceptable performance, it might be centralized in clinical laboratories, keeping the RT-PCR in a second phase for confirmation. Copyright © 2021 Elsevier Ltd. All rights reserved.

Report this publication


Seen <100 times