Comparative Evaluation of Different SARS-CoV-2 Rapid Point-of-Care Antigen Tests with SARS-CoV-2 PCR for Diagnosis of COVID-19

Abstract

BACKGROUND: Detection of positive 2019-nCoV nucleic acids by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR)-based assays performed on the upper and lower respiratory samples remains the gold standard for the diagnosis of COVID-19. However, antigen-detecting rapid diagnostic tests can offer a faster (15–30 min) and less expensive way to diagnose active severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection than nucleic acid amplification tests. AIM: Hence, the present study aimed to compare and evaluate the results of different SARS-CoV-2 rapid point-of-care antigen tests with SARS-CoV-2 PCR as a reference method. METHODS: Sixty-five nasopharyngeal swab specimens were collected from attendees of the Reference Laboratory of Egyptian university hospitals. The samples were placed in viral transport medium for RNA extraction. The remaining part of the suspension was stored at −70°C until use for COVID-19 antigen testing. All samples were processed for the COVID-19 Ag rapid test and RT-PCR simultaneously. RESULTS: RT-PCR assay revealed 46 (70.8%) positive samples and 19 (29.2%) negative samples for COVID-19. All eight rapid antigen assays indicated specificity and positive predictive value of 100% each. As for the other parameters, the sensitivity, negative predictive value (NPV), and accuracy ranged from 43.8 to 93.8, 33.3 to 90, and 60 to 96, respectively. Biozak exhibited the best performance with the highest sensitivities 91.3, 81.8, and 93.75, respectively, while Viro and Standard Q were the worst among the tested kits with sensitivity, NPV, and accuracy of 50, 33.3, and 60 each. Regarding the relationship between the viral load of COVID-19 detected by RT-PCR and the results of the eight rapid antigen tests (RAT), we deduced that the higher the viral load, the better the sensitivity observed. CONCLUSION: The RATs used, in our study, exhibited heterogeneous diagnostic performance, where some of them showed very promising results in comparison to the reference RT-PCR assay.