Diagnosis of COVID-19 obtained by rapid antigen test and reverse transcription–polymerase chain reaction in a medical college in Eastern India-a record-based observational descriptive study

Abstract

Background: In December 2019 in Wuhan, China, a new coronavirus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) appeared. Gradually, the virus started spreading around the world, which was life-threatening. Aims and Objectives: The study’s objective was to find out the positivity rate of infection, the category of patients included in the study, the percentage of positive and negative cases, comparison of rapid antigen detection in relation to real-time reverse transcription–polymerase chain reaction (RT-PCR) test, and rapid antigen detection test’s sensitivity and specificity. Materials and Methods: Eight hundred sixty-five patients’ samples and nasopharyngeal swabs were collected within 3 months as routine samples. Two hundred thirty-two samples were compared by both rapid antigen test (RAT) and RT-PCR. To rule out false negatives, those who tested negative for COVID-19 using a RAT underwent testing by RT-PCR. To rule out false positives, a small number of patients who tested positive for COVID-19 by RAT also underwent validation by RT-PCR test. Results: Two hundred thirty-two samples were obtained for rapid antigen detection, then RT-PCR testing. Both the results were compared. According to the findings, the positivity rate of COVID-19 infection was 0.86%. Two patients (0.86%) tested positive (either by one or both methods) and the number of patients who tested negative was 230 (99.14%). RAT sensitivity and specificity were 50% and 100%, respectively, compared to gold standard RT-PCR. The positive predictive value was 100% and the negative predictive value was 99%. Conclusion: We conclude that antigen detection methods are less sensitive than real-time RT-PCR but they can be used for COVID-19 mass screening and can be used as a quick diagnostic tool in remote locations without molecular testing facilities.