ISSN: 0973-7510

E-ISSN: 2581-690X

Research Article | Open Access
Vidyut Prakash1, Kumar Saurabh2 , Rishikesh Kumar2,
Randhir Kumar2, Namrata Kumari2 and Shailesh Kumar2
1Department of Radiation Oncology, Indira Gandhi Institute of Medical Sciences, Sheikhpura, Patna, Bihar, India.
2Department of Microbiology, Indira Gandhi Institute of Medical Sciences, Sheikhpura, Patna, Bihar, India.
Article Number: 8529 | © The Author(s). 2023
J Pure Appl Microbiol. 2023;17(4):2316-2323.
Received: 25 February 2023 | Accepted: 14 October 2023 | Published online: 20 November 2023
Issue online: December 2023

SARS-CoV-2 is highly contagious, which spreads even by patients having no clinical symptoms or also from people suffering with only mild symptoms. The gold standard test for its diagnosis is reverse-transcription PCR (RT-PCR) but at times of pandemic, Rapid antigen tests (RAT) are required, which has a very less turn-around time. Evaluation of the performance of COVID-19 Rapid antigen test in comparison to SARS-CoV-2 RT-PCR using nasopharyngeal swab, in relation to RNA dependent RNA polymerase (RdRp) Cycle threshold (Ct) values. This observational and cross-sectional study was done on patients coming with features of Influenza-like illness (ILI) or for any aerosol generating procedure or on high-risk patients seeking hospitalization. Both RT-PCR and RAT for COVID-19 were done on samples collected from each patient and results were compared. Altogether, 5314 samples were tested, out of which 104 (01.95 %) & 229 (04.31 %) samples were found positive by the RAT & RT PCR test, respectively. Sensitivity, specificity, PPV and NPV of RAT were found to be 44.54%, 99.96%, 98.08% and 97.56%, respectively. 98.9 % of samples with Ct value ≤ 20 were positive by RAT, whereas only 2.2% samples having Ct value ≥ 26 were found to be positive. Cases having lower Ct values were found to be more symptomatic and vice-versa. RAT are not efficient in detecting the virus in samples showing high Ct values (Ct ≥ 26) by RT-PCR test. Patients with samples showing low Ct values (Ct ≤ 20) had more severe symptoms and vice-versa.


SARS-CoV-2, COVID-19, Reverse Transcription Polymerase Chain Reaction, Rapid Antigen Test, RNA Dependent RNA Polymerase

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© The Author(s) 2023. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.