Health workers are at high risk for SARS-CoV-2 infection and, if asymptomatic, for transmitting the virus on to fragile cancer patients. We screened 512 health workers of our Cancer Institute with rapid serological test Viva-Diag analyzing, with colorimetric test,IgG/IgM- COVID-19 associated. Five subjects (1%) resulted with Viva-Diag test not-negative for IgM. All of them had rt-PCR SARS-CoV-2 test negative while for 2 out of 5 cases, CLIA analysis confirmed positive IgM expression. In this original study on health workers we demonstrated that Viva-Diag is able to evidence subjects positive for IgM expression. However, discordant results with respect to rt-PCR and CLIA assays clearly refer to further studies to optimize the utilization of the serological test in asymptomatic and in at risk subjects.