StructureDefinition

StructureDefinition is a fundamental resource in HL7 FHIR (Fast Healthcare Interoperability Resources) used to define the structure of data. It describes the expected elements, their data types, cardinality, and constraints for a particular data concept. Think of it as a blueprint for how information should be organized.

A StructureDefinition can define a new resource type, an existing resource type with modifications, a data type, or a logical model. For example, a StructureDefinition might describe the elements of a Patient resource, specifying that it must have a name, a birth date, and optionally an identifier. It can also define extensions, which are custom elements that can be added to existing FHIR resources to capture information not covered by the standard profiles.

By using StructureDefinitions, FHIR achieves interoperability by ensuring that systems understand the meaning and format of data being exchanged. They provide a formal, machine-readable way to represent data models, enabling validation and consistency checks. Implementers use StructureDefinitions to build profiles, which are more specific versions of a base resource or data type tailored to a particular use case or context. These profiles further refine the structure, adding constraints and business rules.