Terminologies
This page and it's contents deal with the process of using codes from external code systems (classifications, terminologies, and ontologies), and with the way this is controlled, as well as indexing all the specific related definitions from throughout the specification
Basic Concepts
This table summarises the basic parts on which the terminologies infrastructure is built.
| Word | Meaning | Example |
|---|---|---|
| Concept | A definition of a unitary mental representation of a real or abstract thing | "Hepatitis - a viral infection of the liver" |
| Code | A sequence of characters that represent a concept | "M" for male "1609-7" for Prolaction |
| Code System | A managed collection of codes that identify concept May make rules about how concepts are conceived and defined May allow complex expression as codes |
Snomed-CT, Loinc, ICD-X Name Uses (below) Application Table for Gender |
| Value Set | a uniquely identifiable definition of a set of valid or concepts May be defined by listing codes or by defining criteria for valid codes |
[M,F,I]All Snomed ProceduresAll Snomed-CT and Loinc codes |
| Concept Domain | A named category of like concepts Defines the kinds of codes allowed without defining the set of actual codes |
"Lab Test Codes" Qualification Codes |
| Realm | A context of use where some Concept Domains are bound to particular value sets | Countries Projects Pediatrics |
Full definitions, with discussion, may be found in the HL7 core principles in section 5.1.
This specification allows elements to be "bound" to specific code systems, value sets, or concept domains, meaning that they can only contain the codes (and concepts) allowed by their binding. Usually these elements are of type Concept, though in simple infrastructural cases a simple code is used to refer to a code system directly.
Defined Code Systems
This specification also defines a number of simple code systems that are used internally to represent structural concepts. All the codes is these code systems are case sensitive, and must be used in lowercase.
| Registered Systems | Codes assigned to recognized public code systems and identifiers |
| Internal Codes | A collection of useful codes used in the models, including the list of resource types defined in this specification |
| Identifier Types | Types of identifiers such as "Medical Record Number", "Episode Identifier", etc |
| Name Part Type | The type of a part of a name |
| Name Part Uses | The uses for a part of a name |
| Name Uses | Uses for a Name |
| Address Part Type | The type of part of an address |
| Address Uses | Uses for an address |
| Contact Capabilities | The capabilities of a contact |
| Contact Uses | Uses for an contact address |
| Language Uses | How a person uses a language |
In addition to this, a number of code sytems are defined informally through the specification, including Logical Interactions, Data Absent Reason, and Transaction Actions.
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