EU Health Data API, published by HL7 Europe. This guide is not an authorized publication; it is the continuous build for version 0.1.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/euridice-org/eu-health-data-api/ and changes regularly. See the Directory of published versions

Relationship to XDS/XCA

Many European healthcare systems currently use IHE XDS (Cross-Enterprise Document Sharing) and XCA (Cross-Community Access) infrastructures for document exchange. This Implementation Guide uses IHE MHD (Mobile Health Documents) which serves as a bridge between traditional XDS/XCA environments and modern FHIR-based systems.

IHE MHD as a Bridge

MHD provides a FHIR-based interface for document sharing that can be implemented:

1. Natively - As a direct FHIR-based document sharing system
2. As a Facade - As a FHIR interface in front of existing XDS/XCA infrastructure

This allows Member States with existing XDS/XCA infrastructure to expose FHIR-based APIs without replacing their underlying systems.

Perspective from XDS/XCA Environments

From the perspective of XDS/XCA infrastructure:

• MHD DocumentReference maps to XDS DocumentEntry
• MHD transactions can be translated to XDS transactions
• Existing national infrastructure investments are preserved

Perspective from FHIR Environments

From the perspective of FHIR-native systems:

• Clean, RESTful FHIR API with no XDS dependencies
• Uses standard FHIR resources (DocumentReference, Binary)
• Integrates naturally with other FHIR resources

Implementation Options

Member States can choose the approach that best fits their current infrastructure:

• Pure FHIR implementation
• MHD facade over XDS/XCA
• Hybrid approaches