is currently available in American English, British English, Spanish, Danish and Swedish, with other translations underway or nearly completed in French and Dutch. SNOMED CT cross maps to other terminologies, such as: ICD-9-CM, ICD-10, ICD-O-3, ICD-10-AM, Laboratory LOINC and OPCS-4. It supports ANSI, DICOM, HL7, and ISO standards. Structure SNOMED CT consists of four primary core components: Concept Codes – numerical codes that identify clinical terms, primitive or defined, organized in hierarchies Descriptions – textual descriptions of Concept Codes Relationships – relationships between Concept Codes that have a related meaning Reference Sets – used to group Concepts or Descriptions into sets, including reference sets and cross-maps to other classifications and standards. SNOMED CT "Concepts" are representational units that categorize all the things that characterize healthcare processes and need to be recorded therein. In 2011, SNOMED CT included more than 311,000 concepts, which are uniquely identified by a concept ID, e.g. the concept 22298006 refers to Myocardial infarction. All SNOMED CT concepts are organized into acyclic taxonomic (is-a) hierarchies; for example, Viral pneumonia IS-A Infectious pneumonia IS-A Pneumonia IS-A Lung disease. Concepts may have multiple parents, for example Infectious pneumonia is also a child of Infectious disease. The taxonomic structure allows data to be recorded and later accessed at different levels of aggregation. SNOMED CT concepts are linked by approximately 1,360,000 links, called relationships. Concepts are further described by various clinical terms or phrases, called Descriptions, which are divided into Fully Specified Names (FSNs), Preferred Terms (PTs), and Synonyms. Each Concept has exactly one FSN, which is unique across all of SNOMED CT. It has, in addition, exactly one PT, which has been decided by a group of clinicians to be the most common way of expressing the meaning of the concept. It may have zero to many Synonyms. Synonyms are additional terms and phrases used to refer to this concept. They do not have to be unique or unambiguous. Semantic tag SNOMED CT assigns each concept a semantic tag. It is present in parenthesis in Fully Specified Name of each concept. There can be multiple semantic tags used within each SNOMED CT top level hierarchy. For example, top level hierarchy of Pharmaceutical/biologic Product uses semantic tags of: product, medicinal product, medicinal product form and clinical drug. Only one semantic tag can be used for each concept. The formal model underlying SNOMED CT SNOMED CT can be characterized as a multilingual