1. IntroductionMethods & MaterialsResults Conclusions The Office of Standards and Interoperability (OFTSI) of the Foundation TicSalut, is working on the need of a vocabulary that allows single representation of the content of clinical documents for its automatic and unequivocally interpretation between systems. This interchange must be accurately and could be in different languages. The main objective is to facilitate the access to relevant information for clinical decision making. In order to work the content in this concrete environment and its implementation in the shared medical records system in Catalonia, we have created subsets of the SNOMED CT terminology. The method followed consist on work in concrete realms, proposing subsets that will be validated by a group of experts in its domain. The main phases of the workflow with its involved actors are: 1.Analysis of requirements (all the roles). 2.Identification of the axis of the subset in SNOMED CT (Technician of terminology). 3.Proposal of the members of the subset (Technician of terminology). 4.Validation of these components (Team of clinical documentalists). 5.Clinical validation (Team of experts in the subset domain). 6.Publication (Technician of terminology). 7.Maintenance (Final user) 8.Use (healthcare professionals). The complete flow could be seen in the methodology presented below: We can see in the diagram that it considers the creation of cross references sets, as an often necessary part in the subset creation. The use of mapping between SNOMED CT and local classifications allows us to use SNOMED CT as a reference terminology, reducing the impact of its adoption in the information systems. Following the methodology previously presented, we have created subsets for pathology and immunizations realms. Anatomic Pathology subset (AP subset) contains more than 71,000 concepts and it will be incremented in 900 more soon. We have also defined a micro glossary of 3,900 concepts. It could be seen as a subset of the AP subset, and works as a list of common terms. The initial Immunizations subset we have created contains over 40 concepts of the substances axis. Other domains we are working on are allergies and surgical procedures, but these subsets are not finished yet. We have learned that to take the advantages of SNOMED CT and use it correctly, is necessary adapt it to the local needs. The strategy based on the creation of subsets is the most effective way to implant SNOMED CT but is not enough. The standard is quite flexible, and we can take this characteristic to solve the concrete requirements of each case of use. SNOMED CT has mechanisms to adapt it, like the possibility to translate it or to define extensions of its content. In Catalonia, the creation of subsets had included the translation of the terms into the regional language and the creation of concepts. All these new components are in the Catalan national extension, which we manage in line with our National Release Center. The methodology used in these process has been created by OFTSI to obtain a common way to create subsets of SNOMED CT. We have verified that this diagram allows to plan process of creating subsets in a more easy and effective way. An experience of creating subsets in SNOMED CT Authors: Rius A, Gallego C, Guamis X, Nozal M, Rovira M, Canela J, Manyach J, Cornet J. Location: Catalonia (Spain) Abstract SNOMED CT has been selected as the reference terminology for the shared medical records system in Catalonia. The strategy followed to implant SNOMED CT is based on the creation of subsets and the adaption of the terminology. This approach has required the definition of a methodology to create subsets and the elaboration of an extension to solve the local needs of the Catalan Health System. MEETING OF THE WHO COLLABORATING CENTRES FOR THE FAMILY OF INTERNATIONAL CLASSIFICATIONS 29 October-4 November 2011 Cape Town, Republic of South- Africa D035p