Analytical performances of the COVISTIX and Panbio antigen rapid tests for SARS-CoV-2 detection in an unselected population (all commers)

Importance: A steady increase in acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases worldwide is causing some regions of the world to withstand a third or even fourth wave of contagion. Swift detection of SARS-CoV-2 infection is paramount for the containment of cases, prevention of sustained contagion; and most importantly, for the reduction of mortality. Objective: To evaluate the performance and validity of the COVISTIXTM rapid antigen test, for the detection of SARS-CoV-2 in an unselected population and compare it to PanbioTM rapid antigen test and RT-PCR. Design: This is comparative effectiveness study; samples were collected at two point-of-care facilities in Mexico City between May and August 2021. Participants: Recruited individuals were probable COVID-19 cases, either symptomatic or asymptomatic persons that were at risk of infection due to close contact to SARS-CoV-2 positive cases. Diagnostic intervention: RT-PCR was used as gold standard for detection of SARS-CoV-2 in nasal and nasopharyngeal swabs, study subjects were tested in parallel either with the COVISTIXTM or with PanbioTM rapid antigen test. Main outcome: Diagnostic performance of the COVISTIXTM assay is adequate in all commers since its accuracy parameters were not affected in samples collected after 7 days of symptom onset, and it detected almost 65% of samples with a Ct-value between 30 and 34. Results: For the population tested with COVISTIXTM (n=783), specificity and sensitivity of the was 96.0% (CI95% 94.0-98.0) and 81% (CI95% 76.0-85.0), as for the PanbioTM (n=2202) population, was 99.0% (CI95%: 0.99-1.00) and 62% (CI%: 58.0-64.0%), respectively. Conclusions and relevance: The COVISTIXTM rapid antigen test shows a high performance in all comers, thus, this test is also adequate for testing patients who have passed the peak of viral shedding or for asymptomatic patients.