Low performance of rapid antigen detection test as frontline testing for COVID-19 diagnosis

Highlights • Coris COVID-19 Ag Respi-Strip should not be used alone for COVID-19 diagnosis. • Coris COVID-19 Ag Respi-Strip shows no benefit in reducing the use of RT-qPCR. • Highest viral load is associated with better antigen detection rates.
Background Ensuring accurate diagnosis is essential to limit the spread of the SARS-CoV-2 and for the clinical management of COVID-19. Although real-time reverse transcription polymerase chain reaction (RT- qPCR) is the current recommended laboratory method to diagnose SARS-CoV-2 acute infection, several factors such as requirement of special equipment and skilled staff limit the use of these time-consuming molecular techniques. Recently, several easy to perform rapid antigen detection tests were developed and recommended in some countries as the first line of diagnostic. Objectives The aim of this study was to evaluate the performances of the Coris COVID-19 Ag Respi-Strip. Study design. We performed a comparison study by testing nasopharyngeal samples with RT-qPCR and antigen rapid test. Results 148 nasopharyngeal swabs were tested. Amongst the 106 positive RT-qPCR samples, 32 were detected by the rapid antigen test, given an overall sensitivity of 30.2%. All the samples detected positive with the antigen rapid tests were also positive with RT-qPCR. Conclusions Highest viral load is associated with better antigen detection rates. Unfortunately, the overall poor sensitivity of the COVID-19 Ag Respi-Strip does not allow using it alone as the frontline testing for COVID-19 diagnosis.