Clinical meanings of rapid serological assay in patients tested for SARS-Co2 RT-PCR

Angelo Virgilio Paradiso; Simona De Summa; Daniela Loconsole; Vito Procacci; Anna Sallustio; Francesca Centrone; Nicola Silvestris; Vito Cafagna; Giuseppe De Palma; Antonio Tufaro; Vito Garrisi; Maria Chironna

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.03.20052183 doi: medRxiv preprint symptom appearance is accompanied by an improvement in serological test sensitivity compared to standard molecular testing Our study has some important limitations. Firstly, the Viva-Diag TM test is based on a colorimetric evaluation of the IgG and IgM bands by the operator thus implying all the limitations that a qualitative inter-intra-operator evaluation produce in terms of variability (15) . In our study, this aspect was partially solved by resorting to double operator evaluation and taking picture of all test results to be re-analyzed by a third party in the case of first level evaluation disagreement. However, in this regard, our next step of research to overcome the issues met,will be to use quantitative immunoenzymatic methods to analyze SARS-CoV-2 specific immunoglobulins (16) . A further limitation of our study regarded the fact that the neutralizing antibodies used in the Viva-diag TM test might cross-react with other corona-virus antigens, like those of the SARS-CoV. The recombinant antigen utilized in Viva-Diagis the receptor binding domain of SARS-CoV-2 spike protein for which information on possible cross-reactivity with other corona and flu viruses has not yet been studied (9) . Further studies are urgently needed to definitely clarify this point.