Diagnostic performance of CerTest and Panbio antigen rapid diagnostic tests to diagnose SARS-CoV-2 infection

Objectives: Antigen rapid diagnostic tests (Ag-RDT) have been developed as reliable tools to control the SARSCoV-2 pandemic. The objective of our study was to evaluate the diagnostic performance of two Ag-RDTs. Methods: We evaluated CerTest SARS-CoV-2 Ag One Step Card Test and Panbio COVID-19 Ag Rapid Test Device AgRDTs. We included 320 nasopharyngeal samples: 150 PCR negative samples to assess the specificity and 170 PCR positive samples to evaluate the sensitivity. We also evaluated their sensitivity according to cycle threshold (Ct) values and the time from the onset of symptoms. Tests were compared using the McNemar?s test and agreement was evaluated using the kappa score (k). Results: Both Ag-RDTs showed a specificity of 100 %. Overall sensitivity was 53.5 % for CerTest and 60.0 % for Panbio. For samples with Ct < 25, sensitivity was 94.0 % for CerTest and 96.4 % for Panbio (p = 0.500). Regarding samples with Ct>25, sensitivity was 14.0 % for CerTest and 24.4 % for Panbio (p = 0.004). Sensitivity for samples within the first 5 days after the onset of symptoms were 84.8 % for CerTest and 91.3 % for Panbio (p = 0.250) and notably decreased for samples taken after the fifth day. Both Ag-RDTs showed an excellent agreement between them (agreement = 96.7 %, k = 0.920). Agreement with PCR was also excellent for high viral load samples (Ct<25) for CerTest (98.0 %, k = 0.954) and Panbio (98.8 %, k = 0.973). Conclusions: CerTest SARS-CoV-2 and Panbio COVID-19 Ag showed excellent performance and agreement results for samples with high viral loads (Ct < 25) or samples taken within the first 5 days after the onset of symptoms.

Automated summary

The study showed that both CerTest and Panbio Ag-RDTs demonstrated excellent specificity but lower sensitivity. Higher sensitivity was observed when Ct values were <25, while significantly lower sensitivity was noted with Ct >25. Samples taken within the first 5 days of symptom onset showed higher sensitivity for both tests. Both Ag-RDTs exhibited excellent agreement with each other and with PCR for samples with high viral loads or those taken within the first 5 days after symptom onset.