A concept map defines a mapping from a set of concepts defined in a code system (commonly referred to as the “system”) to one or more concepts defined in other code systems. In the mapping context, a system can be a typical code system based on a recognized standard or local terminology (in any of its forms), or in some cases it may be an “implicit” code system that is not based on a recognized terminology but still represents a set of “concepts” that can be usefully mapped. Mappings are one way – from the source to the target system. In many cases, the reverse mappings are valid, but this cannot be assumed to be the case.
Mappings between code system concepts are only intended to be defined in the context of a particular business usage. The business use case is normally defined by the specification of the source and target value sets. The mappings may be useful in other contexts, but this must be determined based on the context of use and meaning; it cannot be taken for granted automatically. An example where the usage context is important for choosing the correct mapping is mapping from a clinical terminology (e.g. SNOMED CT-Systematized Nomenclature of Medicine Clinical Terms) to a classification (e.g. ICD-10, International Classification of Diseases 10th Revision) for either data analysis or billing. Mappings in the data analysis context would be targeted for an appropriate classification (often at a higher level), whereas in the billing context there may be specific requirements to be met (e.g. leaf level codes only) that could result in multiple mappings for a single source concept and then require additional information beyond the source concept itself in order to select the correct final mapping.
Note that all code systems (explicit or implicit) represented in FHIR have URI (Uniform Resource Identifier) identifiers for value sets (also either explicit or implicit) that include the entire code system, and these “all codes” value sets can be used for mappings that are valid in all use contexts that are appropriate for the code system.
Each mapping for a concept from the source to target system includes an equivalence property that specifies how similar the mapping is (or, in some cases, that there is no valid mapping). There is one element for each concept or field in the source value set or system that needs to be mapped. Each source concept may have multiple targets:
– because there are multiple possible mappings (e.g., ambiguous)
– to specify a correct map, and specify other mappings as invalid
– when there are multiple mappings depending on the values of other elements (dependsOn)
There should be at least one target for each element, but some incomplete concept maps might not have a target for each concept.
A key concept for the Concept Map resource is the translate operation. This operation is a formal definition of an API by which a terminology server can allow clients to ask for a translation to be done based on the content in the Concept Map resource. As such it also provides a useful perspective on the operational use of Concept Map resources in any context.
Fast Healthcare Interoperability Resources (FHIR) is a draft standard describing data formats and elements (known as “resources”) and an application programming interface (API) for exchanging electronic health records. The standard was created by the Health Level Seven International (HL7) health-care standards organization.
Its goal is to facilitate interoperation between legacy healthcare systems, to make it easy to provide healthcare information to healthcare providers and individuals on a wide variety of devices from computers to tablets to cell phones, and to allow third-party application developers to provide medical applications which can be easily integrated into existing systems.
FHIR provides an alternative to document-centric approaches by directly exposing discrete data elements as services. For example, basic elements of healthcare like patients, admissions, diagnostic reports and medications can each be retrieved and manipulated via their own resource URLs (Uniform Resource Locators). FHIR was supported at an American Medical Informatics Association meeting by many EHR (Electronic Health Record) vendors which value its open and extensible nature.