North West Genomic Medicine Service Alliance, published by NHS North West GMSA. This guide is not an authorized publication; it is the continuous build for version 0.0.7 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/nw-gmsa/R4/ and changes regularly. See the Directory of published versions

Health Information Exchange (HIE)

Reference Standards

1. Health Information Exchange (IHE)
   • IHE HIE White Paper
   • HL7 Intermediataries White Paper
2. IHE Cross-Enterprise Document Sharing (XDS.b) XML
3. IHE Mobile access to Health Documents (MHD) HL7 FHIR
4. IHE Query for Existing Data Mobile (QEDm) HL7 FHIR

Actors and Transactions

Actor	Definition
Document Consumer	A system (e.g., an EHR or healthcare app) that requests documents (such as patient records, lab results, or images). It initiates queries and retrieves the actual documents.
Document Source	The system that creates or owns a document (e.g., a hospital EHR, lab system, or imaging system). Responsible for sending the document and its metadata.
Document Recipient	The system that receives, stores, and indexes the submitted document. It consists of: Document Registry and Document Repository
Document Responder	The system that responds to the consumer’s requests. It contains two main parts: Document Registry and Document Repository
Document Registry	Stores metadata (indexes) about available documents (e.g., type, patient ID, creation date, author), not the actual documents. It helps the consumer find what documents exist.
Document Repository	Stores the actual documents (clinical content). Once a document is identified, this is where it’s retrieved from.
Clinical Data Consumer	A system or application (e.g., mobile health app, EHR system, patient portal) that needs to access existing clinical data.
Clinical Data Source	The system that stores and manages the clinical data (e.g., EHR database, hospital information system, lab system). It responds to queries by providing the requested patient data.

In the North West region the HIE systems are:

• Document Registry
  • Greater Manchester Care Record
  • Share2Care
• Document Repository
  • Greater Manchester Care Record
  • Share2Care
  • NW GMSA Clinical Data Repository
• Clinical Data Source
  • Greater Manchester Care Record
  • NW GMSA Clinical Data Repository

Publish a Document

Publish a Document

Interactions (Publishing Options)

The Document Source sends documents to the Document Recipient using one of several possible methods:

• Provide and Register Document Set-b [ITI-41]
  • Classic IHE XDS transaction.
  • Sends both the document(s) and their metadata in a structured set.
• Provide Document Bundle [ITI-65]
  • FHIR-based transaction.
  • Sends a document (e.g., CDA, PDF) wrapped in a FHIR Bundle along with metadata.
• Simplified Publish [ITI-105]
  • A simplified publication mechanism for certain use cases, requiring fewer steps.
• Generate Metadata [ITI-106]
  • Used when the document source wants the recipient to generate metadata automatically (instead of providing it explicitly).

Search and Retrieve document

Search and Retrieve document

Interactions

• Search (Querying for Documents)
  • The Document Consumer sends queries to the Document Registry.
  • Supported interactions:
    • Registry Stored Query [ITI-18] → Standard stored query mechanism to search by patient ID, document type, date, etc.
    • Find Document References [ITI-67] → A FHIR-based query to find references to available documents.

✅ Goal: Find references to documents (not the actual documents yet).

• Retrieve (Getting the Documents)
  • After finding references, the Document Consumer retrieves the documents from the Document Repository.
  • Supported interactions:
    • Retrieve Document Set [ITI-43] → Used to retrieve one or more documents from a repository.
    • Retrieve Document [ITI-68] → FHIR-based retrieval of a specific document.

✅ Goal: Get the actual document content (e.g., PDF, CDA, images).

Strengths:

• Good for sharing legal clinical documents (signed, immutable records).
• Provides a registry for organized search.
• Strong governance and audit support.

Limitations:

• Data inside documents may be hard to query directly (need to download and parse).
• Best for document-level interoperability, not fine-grained data queries.

Query Clinical Data

Query Clinical Data

• This is the IHE transaction for mobile clinical data access.
• It is FHIR-based and allows the Clinical Data Consumer to query and retrieve structured clinical data directly from the Clinical Data Source.
• Examples of data that can be retrieved:
  • Patient demographics
  • Allergies
  • Medications
  • Problems/diagnoses
  • Lab results
  • Clinical notes

Strengths:

• Fine-grained access: you can retrieve just a lab result, allergy list, or active medications.
• More real-time and lightweight, well-suited for mobile and modern apps.
• Easier integration with FHIR APIs.

Limitations:

• No central registry — consumers must know which sources to query.
• Less emphasis on document integrity (since it’s data fragments, not signed documents).
• Governance may be more complex across multiple data sources.

Side-by-Side Comparison

Feature	Document Sharing (XDS, ITI transactions)	Clinical Data Query (PCC-44)
Data Type	Whole documents (CDA/FHIR Documents, PDF, images)	Discrete data (FHIR resources)
Query Target	Document Registry (then repository)	Direct Data Source
Retrieval	ITI-43, ITI-68 (document content)	PCC-44 (FHIR resources)
Use Case	Legal record exchange, discharge summaries, imaging reports	Mobile apps, clinical decision support, patient-facing apps
Strength	Strong governance, legal compliance, document integrity	Flexible, real-time, fine-grained data access
Limitation	Less flexible for data analytics	No document-level legal record