SNOWED CT: clinic and health data representation

For decades effort are being made to develop vocabularies for representing data related to health: testing, measuring, equipment, clinical data, pathologies and diseases, description of the human body, chemicals, etc. The main objective is to facilitate the exchange of information between administrations to improve health services and data integration to promote health research. In the twenty-first century with the advent of technology such as web services and the consequent processing capabilities of large volumes of data, this exchange and integration of information has taken on a new dimension, in which the publication of data has started to play a decisive role.

However, vocabularies that can express in a structured manner the clinical and health data are needed. This is the case of SNOMED CT (or SNOMED Clinical Terms), a standard vocabulary covering more than 300,000 concepts which is the world reference for the representation of medical and health data. 

NOMED CT is a multilingual thesaurus that provides codes, concepts, synonyms and descriptions for description and annotation of documents and medical records (medical records of patients of any hospital). Thus, SNOMED CT includes elements for the description of symptoms, surgical instruments, diagnostic procedures, anatomical structures and body parts, organisms and etiologies, substances, active ingredients, etc. In any case, SNOMED CT is designed to allow the construction of complex expressions, beyond the simple labeling performed by other classifications. For example, it can "coordinate" concepts to form complex concepts ("right knee" = [knee] + [Right side]). In addition, there are other series of semantic relationships to define concepts ("part / whole", etc.) so SNOMED provides a semantic interpretation, with an ontological basis, according to the profile "EL" from the W3C standard vocabulary: OWL2.

Regarding the publication of open data, SNOMED CT is used in national reference portals as the British National Health Service (NHS) or US counterpart site. In addition SNOMED CT is a key element in international cooperation projects as OHDSI (Observational Health Data Sciences and Informatics), in which research organizations and hospitals around the world are participating, to integrate and publish large volumes of observational data which allow the generation of large-scale medical evidence on disease detection and treatment evaluation.

In Spain, the current Ministry of Health, Social Services and Equality is an ordinary member of the International Health Terminology Standards Development Organisation (IHTSDO), an organization that maintains and distributes SNOMED CT. In addition the Ministry is a National Reference Center for SNOMED CT within the national territory and, among other functions, it is responsible for distributing the terminology, both to public and private organizations, totally free.

Health data hold a great potential, not only because the can change the way health care is understood, but they are also the raw material for new products and value-added services for both government agencies and for private entities. In this context, SNOWED CT represents an essential tool for clinical and health data to be published correctly and easily, facilitating the interoperability and their re-use.