First report on qualitative detection of anti-COVID-19 antibody IgM and IgG in a short series of 98 subjects, healthcare workers and patients, by use an ELISA assay

Objective: The aim is to perform a preliminary testing about the presence of anti-COVID-19 IgM and IgG in a short series of healthcare workers and patients at SS. Antonio e Biagio e Cesare Arrigo Hospital, in Alessandria. Methods: Healthcare workers voluntarily agreed to perform the analysis. For patients, serological test was performed at clinician’s discretion. Detection of anti-COVID-19 IgM and IgG was performed separately by use ELISA assay. In order to perform a comparison age, sex, onset symptoms, RT-PCR result were collected. Results: Serological findings showed that most people with positive SARS-CoV-2 RT-PCR testing developed anti-SARS-CoV-2 IgG 14 days after the date of rhinopharyngeal swab and that anti-SARS-CoV-2 IgG detection was also observed in patients with negative RT-PCR. No anti-SARS-CoV-2 IgM was found. Conclusions: Serological testing may be useful to confirm a previous contact with SARS-CoV-2, but it cannot be used in diagnostics. They need further evidence on its performance and operational utility. At the current state of technological evolution, SARS-CoV-2 IgM and IgG antibodies serological tests can be used to supplement the viral RNA detenction by use RT-PCR.