Pattern Catalog

This page provides a high-level overview of all patterns in the FHIR Implementation Patterns collection.

Our FHIR Pattern Collection

A comprehensive guide to distributed FHIR patterns for interoperability, privacy, and imaging

Key Patterns Covered

Broker - Provide a unified entry point for FHIR operations that routes requests to appropriate backend services based on capability, policy, and context.
Naming and Trading Service - Enable dynamic discovery and selection of FHIR endpoints based on capability requirements and service characteristics, supporting federated healthcare networks.
Security Strategy - Provide pluggable authentication and authorization strategies for different FHIR access contexts (EHR launch, standalone apps, backend services) using the Strategy design pattern.
Privacy Enforcement - Apply patient consent and data use restrictions through FHIR security labels and consent resources, enabling granular privacy controls across healthcare data exchanges.
Audit & Provenance Chain - Implement end-to-end audit logging and provenance tracking through a chain of responsibility pattern, enabling comprehensive traceability for regulatory compliance.
Population Export Pipeline - Orchestrate large-scale data extraction using FHIR Bulk Data APIs with proper authentication and transformation, enabling research and analytics use cases.
De-Identification Adapter - Apply consistent de-identification transformations across FHIR and DICOM data for secondary use scenarios, enabling research while preserving privacy.
Asynchronous Invocation - Handle long-running FHIR operations through asynchronous job management and polling, enabling non-blocking execution of time-consuming processes.
Imaging Bridge - Connect FHIR-based clinical systems with DICOM imaging systems through standardized web APIs, enabling seamless integration between clinical metadata and imaging data.
IID Facade - Provide simplified, URL-based launching of imaging viewers with patient and study context, enabling seamless integration between clinical applications and imaging viewers.
Event Observer - Enable real-time synchronization of clinical context across applications through FHIR subscriptions and FHIRcast, allowing multiple healthcare applications to coordinate their views and workflows.

Key Features

Real-world applicable - Patterns based on actual implementation experiences
Standards-aligned - Built on HL7 FHIR, SMART on FHIR, and related healthcare standards
Comprehensive diagrams - PlantUML class and sequence diagrams for each pattern
Forces analysis - Detailed breakdown of the specific problems each pattern solves

Pattern Organization

The patterns in this collection are organized into logical categories by functional area:

Core - Core patterns form the foundation of any FHIR interoperability system. These patterns focus on fundamental routing, security, and privacy concerns that are essential for healthcare data exchange.
Pipeline - Pipeline patterns focus on data processing and transformation workflows that handle the movement, transformation, and governance of healthcare data.
Imaging - Imaging patterns focus on medical imaging integration and visualization within FHIR-based healthcare systems.
Integration - Integration patterns focus on legacy modernization and capability management, enabling gradual transition from legacy systems to modern FHIR-based architectures.

Each pattern follows a consistent structure derived from classical pattern literature.

Pattern Philosophy

Our approach follows several key principles:

1. Standards-First

All patterns are built on established healthcare standards:

HL7 FHIR for data exchange and APIs
SMART on FHIR for application authorization
DICOMweb for medical imaging integration
IHE profiles for workflow and security patterns

2. Incremental Adoption

Patterns are designed to support:

Phased implementation and migration strategies
Coexistence with legacy systems
Progressive enhancement of capabilities

3. Real-world Validation

Each pattern addresses documented challenges from actual implementations and includes:

Concrete use cases and scenarios
Performance and scalability considerations
Security and privacy implications

Patterns by Category

Core

Core patterns form the foundation of any FHIR interoperability system. These patterns focus on fundamental routing, security, and privacy concerns that are essential for healthcare data exchange.

Broker

Intent: Provide a unified entry point for FHIR operations that routes requests to appropriate backend services based on capability, policy, and context.

Key Benefits:

Unified Interface: Clients interact with a single, stable API
Dynamic Routing: Requests automatically flow to capable endpoints
Policy Enforcement: Consistent application of authorization and consent rules
Operational Visibility: Central point for monitoring and audit

Naming and Trading Service

Intent: Enable dynamic discovery and selection of FHIR endpoints based on capability requirements and service characteristics, supporting federated healthcare networks.

Key Benefits:

Dynamic Discovery: Endpoints can be added or removed without client changes
Capability Matching: Requests automatically route to capable servers
Load Balancing: Traffic distributed across multiple endpoints
Fault Tolerance: Automatic failover when endpoints become unavailable

Security Strategy

Intent: Provide pluggable authentication and authorization strategies for different FHIR access contexts (EHR launch, standalone apps, backend services) using the Strategy design pattern.

Key Benefits:

Flexibility: Support multiple authentication flows in same system
Extensibility: Easy to add new authentication strategies
Separation of Concerns: Authentication logic isolated from business logic
Standards Compliance: Implements SMART on FHIR specifications correctly

Privacy Enforcement

Intent: Apply patient consent and data use restrictions through FHIR security labels and consent resources, enabling granular privacy controls across healthcare data exchanges.

Key Benefits:

Granular Control: Support for complex, context-dependent consent rules
Standards-Based: Built on FHIR Consent and Security Labels
Transparent: Clear audit trail of privacy decisions
Flexible: Supports various consent models and regulatory frameworks

Pipeline

Pipeline patterns focus on data processing and transformation workflows that handle the movement, transformation, and governance of healthcare data.

Audit & Provenance Chain

Intent: Implement end-to-end audit logging and provenance tracking through a chain of responsibility pattern, enabling comprehensive traceability for regulatory compliance.

Key Benefits:

Comprehensive Tracking: Complete audit trail from request to response
Standards Compliance: Implements IHE ATNA/BALP requirements
Data Lineage: Provenance resources track data origins and transformations
Regulatory Support: Supports HIPAA, GDPR audit requirements

Population Export Pipeline

Intent: Orchestrate large-scale data extraction using FHIR Bulk Data APIs with proper authentication and transformation, enabling research and analytics use cases.

Key Benefits:

Scalable Extraction: Handle population-level data volumes
Standards-Based: Built on FHIR Bulk Data specification
Secure: Uses SMART Backend Services authentication
Flexible: Support for filtering, transformation, and multiple destinations

De-Identification Adapter

Intent: Apply consistent de-identification transformations across FHIR and DICOM data for secondary use scenarios, enabling research while preserving privacy.

Key Benefits:

Consistent Processing: Same rules applied to FHIR and DICOM
Policy-Driven: Flexible rules for different use cases
Pseudonymization: Maintain linkage while protecting identity
Standards-Based: Follows HIPAA Safe Harbor and Expert Determination

Asynchronous Invocation

Intent: Handle long-running FHIR operations through asynchronous job management and polling, enabling non-blocking execution of time-consuming processes.

Key Benefits:

Non-blocking Operations: Clients don't wait for long-running processes
Resource Management: Server resources allocated efficiently for long tasks
Progress Visibility: Real-time status and progress information
Fault Tolerance: Retry logic and error handling for unreliable operations

Imaging

Imaging patterns focus on medical imaging integration and visualization within FHIR-based healthcare systems.

Imaging Bridge

Intent: Connect FHIR-based clinical systems with DICOM imaging systems through standardized web APIs, enabling seamless integration between clinical metadata and imaging data.

Key Benefits:

Unified Interface: Single API for both FHIR metadata and DICOM images
Standards Compliance: Uses established FHIR and DICOMweb standards
Security Integration: Maps authentication between FHIR and DICOM contexts
Performance Optimization: Caching and efficient image retrieval

IID Facade

Intent: Provide simplified, URL-based launching of imaging viewers with patient and study context, enabling seamless integration between clinical applications and imaging viewers.

Key Benefits:

Simple Integration: URL-based launching requires minimal integration effort
Viewer Independence: Works with any IID-compliant viewer
Context Preservation: Patient and study context passed automatically
Deep Linking: Direct access to specific studies or series

Event Observer

Intent: Enable real-time synchronization of clinical context across applications through FHIR subscriptions and FHIRcast, allowing multiple healthcare applications to coordinate their views and workflows.

Key Benefits:

Real-time Synchronization: Immediate context updates across applications
Loose Coupling: Applications don't need direct knowledge of each other
Workflow Efficiency: Reduces manual context entry and switching overhead
Standards Compliance: Built on FHIRcast and FHIR Subscription standards

Integration

Integration patterns focus on legacy modernization and capability management, enabling gradual transition from legacy systems to modern FHIR-based architectures.

Legacy Adapter

Intent: Transform legacy data formats (HL7v2, CDA, DICOM SR) to FHIR while preserving clinical semantics and enabling incremental modernization of healthcare systems.

Key Benefits:

Semantic Preservation: Maintains clinical meaning during transformation
Incremental Migration: Enables gradual modernization without disruption
Standards Compliance: Produces valid FHIR resources with proper profiles
Terminology Mapping: Handles code system translations automatically

Capability Facade

Intent: Provide a simplified interface for querying and managing FHIR server capabilities and configuration, abstracting the complexity of CapabilityStatement parsing.

Key Benefits:

Simplified Queries: Easy to check capabilities without parsing CapabilityStatement
Caching: Capability information cached for performance
Aggregation: Combine capabilities from multiple servers
Abstraction: Hide complexity of capability discovery

Quick Reference Table

Pattern	Category	Intent
Broker	Core	Provide a unified entry point for FHIR operations that routes requests to appropriate backend services based on capability, policy, and context.
Naming and Trading Service	Core	Enable dynamic discovery and selection of FHIR endpoints based on capability requirements and service characteristics, supporting federated healthcare networks.
Security Strategy	Core	Provide pluggable authentication and authorization strategies for different FHIR access contexts (EHR launch, standalone apps, backend services) using the Strategy design pattern.
Privacy Enforcement	Core	Apply patient consent and data use restrictions through FHIR security labels and consent resources, enabling granular privacy controls across healthcare data exchanges.
Audit & Provenance Chain	Pipeline	Implement end-to-end audit logging and provenance tracking through a chain of responsibility pattern, enabling comprehensive traceability for regulatory compliance.
Population Export Pipeline	Pipeline	Orchestrate large-scale data extraction using FHIR Bulk Data APIs with proper authentication and transformation, enabling research and analytics use cases.
De-Identification Adapter	Pipeline	Apply consistent de-identification transformations across FHIR and DICOM data for secondary use scenarios, enabling research while preserving privacy.
Asynchronous Invocation	Pipeline	Handle long-running FHIR operations through asynchronous job management and polling, enabling non-blocking execution of time-consuming processes.
Imaging Bridge	Imaging	Connect FHIR-based clinical systems with DICOM imaging systems through standardized web APIs, enabling seamless integration between clinical metadata and imaging data.
IID Facade	Imaging	Provide simplified, URL-based launching of imaging viewers with patient and study context, enabling seamless integration between clinical applications and imaging viewers.
Event Observer	Imaging	Enable real-time synchronization of clinical context across applications through FHIR subscriptions and FHIRcast, allowing multiple healthcare applications to coordinate their views and workflows.
Legacy Adapter	Integration	Transform legacy data formats (HL7v2, CDA, DICOM SR) to FHIR while preserving clinical semantics and enabling incremental modernization of healthcare systems.
Capability Facade	Integration	Provide a simplified interface for querying and managing FHIR server capabilities and configuration, abstracting the complexity of CapabilityStatement parsing.