RESUMO
OBJECTIVE: To describe the planning and execution process of a massive seroprevalence study for SARS-CoV-2 in professionals of the Hospital Universitario Fundación Alcorcón (HUFA) (Spain). METHODS: A description is presented of the plan designed and developed at the HUFA for the execution of the extraction of the samples for serology from all the professionals who worked in the hospital between 14 and 29 April 2020. A descriptive analysis of the participation of the professionals in the study is carried out. Extraction areas, health personnel, and execution times were planned. A total of 2326 extractions were assigned to health personnel, the remaining extractions were assigned to workers from external companies. RESULTS: A total of 2641 workers (90.5%) out of 2918 candidates participated in the study. The professional category most analysed was nursing with 28.3% (n = 590). The percentage of compliance with schedule planning was 28.6%. Up to a maximum of 298 daily extractions were planned. The busiest day was the 4th day of the study with 399 extractions. CONCLUSIONS: The organising of such a large study, with a 100% coverage of those who worked in the hospital, and with such a great response from the workers involved, has led to obtaining results of high reliability in the seroprevalence study carried out. Although the percentage of participation was very high, the level of compliance with the planning was low.