ImplementationGuide

An IG acts as a table of contents for a specification package. It logically groups related conformance resources—StructureDefinitions, ValueSets, CodeSystems, and CapabilityStatements—into a single, versioned publication. This ensures implementers receive a complete, self-contained set of rules rather than hunting for scattered profiles. The manifest defines the canonical URL and dependency graph, allowing validators to automatically resolve all required components.

The US Core IG defines the minimum conformance requirements for accessing patient data in the United States, based on the U.S. Core Data for Interoperability (USCDI) standard. It profiles foundational resources like Patient, Observation, and MedicationRequest to ensure consistent representation of clinical data across all FHIR implementations in the US healthcare ecosystem.

• Mandates support for OAuth 2.0 and SMART on FHIR authorization
• Profiles 20+ resources including Vital Signs, Laboratory Results, and Clinical Notes
• Required for ONC Health IT Certification under the 21st Century Cures Act
• Serves as the base profile layer that domain-specific IGs build upon

mCODE is a consensus-driven FHIR IG that standardizes the exchange of essential oncology data across research, treatment, and patient care contexts. It profiles resources like CancerPatient, PrimaryCancerCondition, and CancerRelatedSurgicalProcedure to create a common language for cancer data interoperability.

• Developed by the American Society of Clinical Oncology (ASCO) and MITRE
• Enables real-world evidence generation from electronic health records
• Profiles TNM staging, genomic variants, and tumor markers as structured data
• Supports both clinical care coordination and secondary research use cases

The Da Vinci CDex IG defines workflows for requesting and exchanging clinical data between providers and payers using FHIR. It specifies how a health plan can query a provider's FHIR server for attachments, clinical documentation, and quality measure data to support value-based care and prior authorization processes.

• Implements Task-based workflows for solicited and unsolicited data exchange
• Supports signature-required and signature-not-required document retrieval
• Uses FHIR Questionnaire resources to define payer-specific data requirements
• Aligns with HIPAA minimum necessary standards for data disclosure

The IPS IG defines a minimal, non-exhaustive set of clinical data for cross-border patient care, providing a standardized snapshot of a patient's health status. It profiles resources including AllergyIntolerance, MedicationStatement, and Immunization to ensure essential health information is universally interpretable regardless of jurisdiction.

• Mandated by the European eHealth Digital Service Infrastructure (eHDSI)
• Uses SNOMED CT as the primary clinical terminology with LOINC for observations
• Designed for unplanned, cross-border care scenarios
• Implements ISO 27269 international patient summary standard

The Bulk Data Access IG defines an asynchronous API for exporting large, flat datasets of patient-level data from a FHIR server, designed for population-level analytics and machine learning. It uses NDJSON format and Group resources to define cohorts, enabling efficient extraction of millions of records without overwhelming synchronous endpoints.

• Implements kick-off, polling, and deletion pattern for long-running exports
• Supports system-level, patient-level, and group-level export scopes
• Required for CMS Interoperability and Patient Access Rule compliance
• Enables federated analytics without centralizing raw patient data

The Da Vinci PDex IG enables health plans to share member clinical data with providers and third-party applications via FHIR APIs. It specifies how payers expose claims-derived clinical data, medication dispensations, and lab results in a standardized format, supporting the CMS mandate for payer-to-payer data exchange.

• Profiles ExplanationOfBenefit and Coverage resources for payer data
• Implements member-authorized OAuth 2.0 flows for third-party app access
• Supports CDS Hooks integration for real-time clinical decision support
• Aligns with CARIN Blue Button consumer-directed exchange standards

The core profiling mechanism that defines constraints on a base FHIR resource. An ImplementationGuide references multiple StructureDefinitions to specify exactly how generic resources like Patient or Observation must be populated for a specific use case.

• Defines cardinality, must-support flags, and invariant rules
• Constrains optional elements to required for a given context
• Compiled into the IG's formal validation package

A curated set of codes drawn from one or more CodeSystems that constrains terminology binding within a profiled resource. An IG binds ValueSets to specific elements to enforce coded data consistency.

• Defines intensional (rule-based) or extensional (enumerated) code lists
• Binds to elements with strengths: required, extensible, preferred, example
• Ensures semantic interoperability across implementing systems

A declaration of the functional capabilities a FHIR server must support to conform to an IG. It specifies which resources, operations, and search parameters are mandatory or optional.

• Defines the RESTful API contract for implementers
• Declares supported interaction types: read, search, create, update
• Used by clients to discover server functionality at runtime

The conformance testing tool that checks resource instances against the profiles and constraints defined in an ImplementationGuide. It ensures that exchanged data adheres to the IG's rules.

• Validates against base FHIR specification and all referenced profiles
• Checks terminology bindings, cardinality, and invariants
• Available as a Java library, CLI tool, or integrated into HAPI FHIR servers

A domain-specific language for authoring ImplementationGuide artifacts in a concise, human-readable syntax. FSH compiles to standard FHIR JSON definitions, dramatically reducing the effort of IG development.

• Defines profiles, extensions, and value sets with minimal syntax
• Supports inheritance and mixin patterns for profile reuse
• Used by tools like SUSHI to generate complete IG packages

The foundational IG for U.S. healthcare interoperability, defining minimum conformance requirements based on USCDI data classes. It serves as a base profile layer that domain-specific IGs build upon.

• Profiles for Patient, Encounter, Condition, Observation, and more
• Mandates specific terminology bindings like LOINC and SNOMED CT
• Required for ONC Health IT Certification compliance