Comparison of five SARS-CoV-2 rapid antigen tests in a hospital setting and performance of one antigen assay in routine practice. A useful tool to guide isolation precautions?

Van Honacker, Eveline; Van Vaerenbergh, Kristien; Boel, An; De Beenhouwer, Hans; Leroux-Roels, Isabel; Cattoir, Lien

BACKGROUND: In a hospital setting, there is a need for rapid detection of SARS-CoV-2 to guide isolation measures and targeted admission. AIM: First, we evaluated the diagnostic performance of five SARS-CoV-2 rapid nucleocapsid protein antigen detection (RAD) assays (Biosynex, Biotical, Orient Gene, Panbio, SD Biosensor). Secondly, we described the performance and impact of the implementation of the SD Biosensor assay at our emergency department. METHODS: Sensitivity and specificity of the five RAD assays were analyzed on 100 respiratory samples: 60 real-time reverse-transcriptase-polymerase chain reaction (rRT-PCR) confirmed SARS-CoV-2 positive samples, 24 SARS-CoV-2 RNA negative samples and 16 samples positive for other respiratory pathogens. We adapted the manufacturer’s protocol, to validate the antigen tests on transport media used for rRT-PCR in our routine practice. The SD Biosensor RAD assay was implemented as screening method for rapid diagnosis and targeted admission. FINDINGS: Sensitivity of the included RAD assays ranged from 88.9% to 100% for samples with Ct <26, specificity from 46.2% to 100%. During the implementation period, 4195 RAD tests were performed. Due to the rapid RAD result, 157 patients were transferred directly to the COVID-19 cohort instead of the regular ward (n=47) or the temporary COVID-19 ward (n=110). CONCLUSION: The SD Biosensor, Biotical and Panbio SARS-CoV-2 antigen tests had an acceptable overall performance and seem to be able to detect most of the contagious patients. In the context of high prevalence of SARS-CoV-2, RAD tests can be used as a rapid screening tool, to guide infection prevention measures and aid targeted admission.