Evaluation of the Panbio™ COVID-19 Antigen Rapid Diagnostic Test in subjects infected with Omicron using different specimens

Community testing is a crucial tool for the early identification of SARS-CoV-2 infection and transmission control. The emergence of the highly mutated Omicron variant (B.1.1.259) raised concerns about its primary site of replication, impacting sample collection, and its detectability by rapid antigens tests. We tested the Antigen Rapid Diagnostic Test (Ag-RDT) performance using nasal, oral, and saliva specimens for COVID-19 diagnosis in 192 symptomatic individuals, using RT-qPCR from nasopharyngeal samples as control. Variant of Concern (VOC) investigation was determined by the 4Plex SARS-CoV-2 screening kit. SARS-CoV-2 positivity rate was 66.2%, with 99% of the positive samples showing an amplification profile consistent with that of the Omicron variant. Nasal Ag-RDT showed higher sensitivity (89%) than oral (12.6%) and saliva (22.1%) Ag-RDTs. Our data showed the good performance of the Ag-RDT in a pandemic scenario dominated by the Omicron VOC. Furthermore, our data also demonstrated that nasal specimens perform better than oral and saliva ones for Omicron Ag-RDT detection. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was sponsored by Abbott Laboratory Grant # CLDG-1001-BR. The funders had no role in the study design, the data collection, the analysis, the interpretation and decision to publish this study. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The present study was approved by the local ethics review committee from Clementino Fraga Filho University Hospital (CAAE: 30161620.0.0000.5257) and by the national ethical review board (CAAE: 30127020.0.0000.0068). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present work are contained in the manuscript.