An Analogy between Gold Standard SARS-CoV-2 RT-qPCR with the SARS-CoV-2 Rapid Antigen Test in a Tertiary Care Setting in Central State of India

Abstract

Reverse transcription-quantitative PCR (RT-qPCR)-based assays are extensively being utilized to detect coronavirus disease 2019 (COVID-19). However, due to a lack of RT-qPCR testing capability, these tests cannot be carried out in community clinics. The intention of our study was to evaluate the specificity and sensitivity of Rapid Antigen Detection (RAT) tests versus those of RT-qPCR using nasopharyngeal and oropharyngeal specimens. Respiratory swab specimens were collected from the COVID-19 patients admitted at Dr. Bhimrao Ambedkar Memorial Hospital, Raipur, CG, India, during March to April 2022. RAT and RT-qPCR were performed using standard methods as per guidebook instructions, and subjects were chosen using a convenience sample technique. 100 swabs from patients, who had earlier verified positive and 100 from who had earlier verified negative for SARS-CoV-2 via RT-qPCR, were taken for study. Study was approved by the institutional ethical committee before data collection and initiation of the study. We evaluated for the sensitivity and specificity of the STANDARD Q COVID-19 Ag test kit (SD Biosensor). On testing, an over-all sensitivity and specificity of the kit was recorded as 74% and 100%, respectively in comparison to the RT-qPCR kit. Further, the assay’s sensitivity was shown to be 100%, 94.87%, 77.27%, and 55.56%, respectively, for samples with cycle thresholds (Ct) of 15-25, 25-30, 30-35, and >35. We draw the conclusion that the RT-qPCR assay has superior sensitivity and specificity to the antigen assay. However, in all situations where RT-qPCR testing is difficult, the antigen assay could serve as a rapid and simple option for separating SARS-CoV-2 contagious from non-contagious patients.

Keywords

• rapid antigen detection
• rat
• covid-19
• rt-qpcr
• ag-detection
• sars-cov-2