Abstract Objective: To evaluate the performance SERO of two available rapid immunological tests for identification of severe acute respiratory syndrome MESHD Coronavirus 2 ( SARS-CoV-2) antibodies SERO and their subsequent application to a regional screening of health care workers (HCW) in Tuscany (Italy). Design: measures of accuracy and HCW serological surveillance Setting: 6 major health facilities in Tuscany, Italy. Participants: 17,098 HCW of the Tuscany Region. Measures of accuracy were estimated to assess sensitivity SERO in 176 hospitalized Covid-19 clinical subjects at least 14 days after a diagnostic PCR-positive assay result. Specificity was assessed in 295 sera biobanked in the pre-Covid-19 era in winter or summer 2013-14 Main outcome measures: Sensitivity SERO and specificity, and 95% confidence intervals, were measured using two serological tests SERO, named T-1 and T-2. Positive and Negative predictive values SERO were estimated at different levels of prevalence SERO. HCW of the health centers were tested using the serological SERO tests, with a follow- up nasopharyngeal PCR-test swab in positive tested cases. Results: Sensitivity SERO was estimated as 99% (95%CI: 95%-100%) and 97% (95% CI: 90%-100%), whereas specificity was the 95% and 92%, for Test T-1 and T-2 respectively. In the historical samples IgM cross-reactions were detected in sera collected during the winter period, probably linked to other human coronaviruses. Out of the 17,098 tested, 3.1% have shown the presence of SARS-CoV-2 IgG antibodies SERO, among them 6.8% were positive at PCR follow-up test on nasopharyngeal swabs. Conclusion Based on the low prevalence SERO estimate observed in this survey, the use of serological test SERO as a stand-alone test is not justified to assess the individual immunity status. Serological tests SERO showed good performance SERO and might be useful in an integrated surveillance, for identification of infected subjects and their contacts as required by the policy of contact tracing TRANS, with the aim to reduce the risk of dissemination, especially in health service facilities.