Role of SARS-COV2 Antigen as a diagnostic test for COVID-19

Document Type : Original Article


1 Medical Virology Department, The Armed Central Laboratories for Medical Research and Blood Bank, Cairo, Egypt

2 Medical Microbiology and Immunology department, Faculty of medicine, Ain Shams University, Cairo, Egypt


Background: Successive waves of SARS-CoV-2 infections with increasing transmission rates may burden the laboratories performing molecular diagnostic testing. Alternative diagnostic methods may provide additional diagnostic capacity. Chemiluminescent totally automated antigen detection test for SARS-CoV-2 (Ortho VITROS SARS-CoV-2 antigen test) could be satisfactory replacement for reverse-transcription quantitative polymerase chain reaction (RT-qPCR) for mass screening during outbreaks. Methods: RT- qPCR and the VITROS® SARS-CoV-2 antigen were compared. Antigen detection test was assessed using clinical samples (nasopharyngeal swabs in viral transport medium) withdrawn from 668 patients suspected to have SARS-CoV-2 infection. Results: From 668 samples, 303 showed SARS-CoV-2 antigens positive and 365 SARS-CoV-2 antigens negative in comparison with RT-qPCR, the sensitivity was 89.11% and the specificity was 100.0% (PPV 100.0 and NPV 91.7). Ct value of 16.0 was the limit of detection of the assay. Conclusion: The given results show that VITROS® assay was acceptable for the detection of patients having contagious COVID-19 in the clinical setting. This test showed high sensitivity and specificity in the SARS-CoV-2 detection in samples with a Ct value of 32 or less. Chemiluminescent full automated antigen detection test for SARS-CoV-2 is a feasible substitute to (RT-qPCR) for mass screening


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