A COMPARATIVE STUDY OF RAPID SARS COV 2 ANTIGEN DETECTION TEST & REAL TIME PCR TEST FOR DIAGNOSIS OF COVID-19 IN TERTIARY CARE INSTITUTE AT KOTA, SOUTH-EAST RAJASTHAN, INDIA

Background:The 2019 (Covid19) pandemic of coronavirus disease was caused by SARS Cov 2 Virus. The emergence of the disease was started from the Wuhan city of China in December 20191. This infection causes asymptomatic and mild diseases more than severe pneumonia. A Rapid Lateral flow immunoassays using monoclonal anti-SARS CoV- 2 antibodies, targeting SARS-CoV-2 antigens, can be used as complementary screening tests if their accuracy comes comparable to that of gold standard real-time RT-PCR assays. Objective:The present study has been conducted retrospectively on the data of patients who underwent for Covid 19 diagnosis by RAT at the Microbiology Department Central Laboratory, Maharao Bhim Singh Hospital Nayapura Kota. Material and Method: Respiratory samples from suspected 5219 COVID-19 patients, mainly nasopharyngeal and throat swabs were collected. COVID-19 Ag Confirmit™ kit (Alpine biomedicals) is a rapidchromatographic immunoassay for the detection ofSARS-CoV-2 nucleoprotein (N) antigen in respiratoryspecimens. Multiplex Real-time RT-PCR kit (TRIVITRON healthcare) was used, whichtargets envelope gene (E), and Orf1ab gene of SARS-CoV-2 genome and RPP30 Human gene as internal control, was used for SARS-CoV-2RNA detection. Descriptive statistics were used to describe the usefulness of rapid diagnostic tests. For that online MedCalcs Diagnostic test evaluation statistical tool10. Result: Among all 5219 samples (n=5219) tested by RT-PCR 785 (15.4%) samples were positive and 4434 (84.95%) were negative. Samples tested by RAT 813 (15.57%) samples were positive & 4406 (84.42%) were negative, in our study we found discordant results in 36 samples. The sensitivity and specificity of the COVID-19 Ag Confirmit™ kit (Alpine biomedicals) were 99.49% and 99.28% respectively. Discussion: Out of 785 RT-PCR-positive samples in our study, the 4 false negative results were tested for SARS-CoV-2 antigen seven days after disease onset. The RT-PCR result of these samples had relatively high Ct-values. Without the present population prevalence of COVID-19, the positive and negative predictive values (PPV and NPV) of the assay could not be accurately calculated. Conclusions: There is comparable Sensitivity and Specificity between Rapid assay for SARS-CoV-2 antigen detection (COVID-19 Ag Confirmit™ kit) and real-time RT-PCR assay.