Rapid antigen detection kit for the diagnosis of SARS-CoV-2 - are we missing asymptomatic patients?

Abstract

PurposeTo determine the utility, diagnostic accuracy, sensitivity, specificity, and negative predictive value of the laboratory based Covid-19 antigen detection test (Coris Bio- Concept, Gembloux, Belgium) for the diagnosis of SARS-CoV-2 in a tertiary care hospital among symptomatic and asymptomatic patients. MethodsThe nasopharyngeal swab samples were collected from the symptomatic patients and their contacts. The diagnostic accuracy of this antigen kit was determined in comparison to SARS-CoV-2 real-time reverse transcriptase (RT-PCR). ResultsA total of 825 patients fulfilling the inclusion criteria were included in the study; RT-PCR and antigen detection was performed simultaneously for 484 samples to determine the sensitivity and specificity of the test. The overall specificity and sensitivity was 99.32% and 71.96% respectively. Also, 3.7% of the asymptomatic patients who were negative by RAT were detected positive by RT-PCR. ConclusionThis rapid antigen test (RAT) was sensitive in the symptomatic patients presenting during the initial phase of the illness. Since, majority of the SARS-CoV-2 patients are asymptomatic and considering the huge population, the testing strategy formulated by Indian Council of Medical Research (ICMR) at the national level was cost effective. Thus, Ag-RDTs could play a pivotal role in early diagnosis, policy making and surveillance of the SARS-CoV-2.