Evaluation of diagnostic performance of a rapid antigen test in diagnosing COVID-19.

The coronavirus disease 2019 (COVID-19) pandemic is our time's major global health crisis and the greatest health challenge. Reverse transcription-polymerase chain reaction (RT-PCR) test for severe acute respiratory syndrome coronavirus (SARS-CoV-2) is the gold standard technique for diagnosis of symptomatic cases and asymptomatic carriers. By 2020, antigen rapid tests have been approved for use in Covid-19 testing by regulatory bodies all over the world owing to their benefits as they are rapid and cost effective. This work aimed to determine the diagnostic sensitivity and accuracy of the SARS-CoV-2 rapid antigen test in the detection of SARS-CoV-2 infection compared to RT-PCR data. The study included 111 symptomatic COVID-19 patients and 20 control subjects. Of the 111 study patients, 91 patients (81.98%) were positive by RT-PCR and 20 patients negative. The BIOZEK antigen COVID-19 Ag rapid test device was evaluated using sera from the 111 symptomatic COVID-19 patients. Of the 91 RT-PCR positive patients, 81 (90.1%) were positive by the antigen rapid diagnostic test (Ag-RDT). The control subjects were negative by both tests. The overall sensitivity, specificity, PPV, NPV, and accuracy of the Ag-RDT were 91.11%, 100%, 100%, 68.9%, and 91.8%, respectively and these increased as the level of viremia increased. In conclusion, the used Ag-RDT showed high sensitivity and accuracy for detecting of a SARS-CoV-2 infection, especially when the viral load was high. However, the test lacks sensitivity particularly in those with low viral load.