Quality assurance is a key element for the functioning of any laboratory, and it goes further than just the internal and external quality controls of analytical parameters. The Spanish Society for Immunology (SEI) promotes a process to select a Center (CR) that will develop a complete program of External Quality Assurance for Diagnostic Immunology Laboratories, associated with the Spanish Society for Immunology (GECLIDSEI). This text presents the main aspects of this process that should allow structuring the GECLID-SEI.