Comparison of the Rapid Antigen Testing Method With RT-qPCR for the Diagnosis of COVID-19.

Ashok Kumar Pandey,Rama S Rath,Subodh Kumar,Aroop Mohanty,Vivek Hada,Rajni Kant,Surekha Kishore

doi:10.7759/cureus.17405

Abstract

Background: Coronavirus disease 2019 (COVID-19) has till now affected about 110 million people globally. It has not spared any country and has led to 24 lakh deaths. As a result, the testing had to be increased manifold leading to depletion in the number of the quantitative reverse transcription polymerase chain reaction (RT-qPCR) kits. Point-of-care rapid antigen-based tests were developed in order to meet the increasing demands. The objective of this study was to compare the performance of a rapid chromatographic test (index test) with a gold standard test (RT-qPCR).Methods: A retrospective analysis was done at a tertiary care teaching hospital in Eastern Uttar Pradesh, India. Paired samples were taken from all patients reporting to the clinic for antigen-based rapid diagnostic testing (RDT) and RT-qPCR. The sensitivity and specificity were calculated to evaluate the performance of the RDT.Results: The overall sensitivity and specificity of the RDT were observed to be 53.6% (39.7-67.0) and 97.35% (94.6-98.9), respectively. In symptomatic individuals, the sensitivity was higher 61.0% (44.5-75.8). The test positivity rates of RDT were found to be higher at a cycle threshold value ≤20.Conclusion: RDT can be used as a screening test to rule in the infection especially in symptomatic patients who are more prone to spread the disease. It is an important weapon in the armamentarium of public healthcare for the containment of COVID-19.

Highlights

Coronaviruses are enveloped non-segmented, positive-sense RNA viruses belonging to the family Coronaviridae and order Nidovirales [1,2]
A total of 321 suspected individuals were tested for rapid antigen testing and RT-qPCR simultaneously
When we compared the test positivity at different cycle threshold (CT) values, we found that the antigen positivity increases from CT values

Summary

Introduction

Coronaviruses are enveloped non-segmented, positive-sense RNA viruses belonging to the family Coronaviridae and order Nidovirales [1,2]. India has reported 31,440,951 confirmed cases of COVID-19 and is ranked second only to the United States of America [7] This growing trend and overwhelming increase in the total number of cases has overburdened our testing capacity and has led to a severe scarcity of molecular testing kits and reagents. The quantitative reverse transcription polymerase chain reaction (RTqPCR) testing requires a sophisticated biosafety level (BSL-2/BSL-3) laboratory and skilled technicians to perform the test It takes a minimum of 8-10 hours for the generation of report from the receiving of the sample. In view of the above, the need of the hour was to develop a point-of-care test that would detect and isolate positive cases rapidly, diagnose them at an early stage and contain the spread This could prove very useful in an emergency department where a quick triage could be done for patients with severe acute respiratory illness (SARI). The objective of this study was to compare the performance of a rapid chromatographic test (index test) with a gold standard test (RT-qPCR)

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Discussion

Conclusion