Objective: The aim of this work was to explore reliability and performance of 4 Ag rapid test device on random clinical specimens routinely collected for SARS-CoV2 diagnosis.
Methods: Run 4 kinds of Ag rapid test devices according to manufacturer’s instructions with negative and positive VTM nasopharyngeal specimens which were preprocessed in a same way.
Results: 47 negative specimens for SARS-CoV2 confirmed by RT-PCR were tested. All the devices showed correct SARS-CoV2 negative results with negative specimens (29 PCR negative for SARS-CoV2 without any request for other diagnosis and 18 PCR negative for SARS-CoV2 but positive for at least one respiratory virus by Panther Fusion®).
86 positive specimens for SARS-CoV2 confirmed by RT-PCR were tested. All the devices showed correct SARS-CoV2 positive results in 60/86 positive specimens. All the devices showed SARS-CoV2 negative results in 16/86 positive specimens. In the remaining 10 specimens testing, 4 devices gave different results.
Conclusion: Rapid Ag test devices are alternative for SARS-CoV2 diagnosis when lacking time or laboratory environment. Nasopharyngeal specimens should be positive by rapid Ag testing if viral burden correspond to Ct of around 30 or less by RT-PCR. At least for devices targeting N Ag, molecular variations within S gene do not influence performance of the test, which is the case for AllTest and Acro Biotech.
Michel Prost and Lara Spiral SA