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Architecture

Introduction

The architecture generally follows Domain Driven Design [DDD], Domain Driven Design and Data Mesh

The general architecture is shown below:

Data Mesh

Data Sharing is based on FHIR RESTful API's, and asynchronous messaging used to deliver the orders and reports in mostly HL7 v2 and IHE Laboratory Testing Workflow (LTW) based .

The diagram below shows multiple interoperability pathways for exchanging diagnostic reports—either as structured data or documents—between systems. It maps out which standards (FHIR, HL7 v2, IHE, XDS/MHD), APIs, and NHS England national services (UGR, NIR, NRL, Genomic OMS, etc.) are involved depending on:

• Which API is used
  • Event API
  • Data Sharing API
• Whether an existing interface already exists
• Whether the exchange is structured data or unstructured documents

NHS England services are coded in blue, while currently implemented services are coded in green.

graph TD
    B[Diagnostic Report Interoperabilty] --> C{"Options <br/>Both answers<br/>are likely"}
    C -->|Event API| D{Existing Interface?}
    C -->|Data Sharing API| E{Document <br/>or Data}
    E --> |Data| Data[Structured]
    E --> |Document<br/>and hybrid| Documents["Unstructured (and Clinical) Documents"]
    Data --> REST["FHIR RESTful API<br/>IHE Query for Existing Data (QEDm)"]
    REST --> UGR[NHS England Unified Genomic Record<br/>NHS England Patient Data Manager]
    Documents --> XDS["FHIR RESTful API<br/>IHE Mobile access to Health Documents (MHD) <br/>or XML SOAP IHE XDS <br/>e.g. NHS England National Record Locator"]
    XDS --> Format{Format}
    Format --> |Binary| Binary[PDF, PMG, html, etc]
    Format --> |Structured - Imaging| RAD[DICOM]
    Format --> |Clinical Document - Laboratory| FHIRDocument["Structured and Unstructured<br/><br/>FHIR Document<br/>e.g. NHS England National Record Locator <br/> e.g. Internation Patient Summary (IPS),<br/>EU Laboratory and Imaging Reports,<br/>XPanDH/EU Hospital Discharge Report (HDR)"]  
    D --> |Yes| V2{Structured or<br/>Unstructured} 
    V2 --> |Structured| LTW[HL7 v2 ORU_R01<br/>IHE Laboratory Testing Workflow LTW LAB-3<br/>and IHE RAD]
    V2 --> |Unstructured| MDM[HL7 v2 MDM_T02 or MDM_T01 <br/> e.g. ICS/LHCRE Systems]
    MDM --> NRL["NHS England National Record Loactor Feed<br/>(POST DocumentReference)<br/>"]
    D --> |No| Workflow[FHIR Workflow <br/> e.g. NHS England Genomic Order Management Service]
    Workflow --> PubSub[FHIR Subscription]
    LTW --> Pathology[FHIR Message <br/> e.g. NHS England Pathology]
    RAD --> NIR[NHS England National Imaging Registry]

    classDef blue fill:#DAE8FC;
    classDef green fill:#D5E8D4;

    class Pathology,UGR,NIR,FHIRDocument,XDS,NRL,Workflow blue
    class LTW,REST,MDM green

Enterprise Integration

The Intermediary, North West GMSA Regional Orchestration Engine (RIE) is an Enterprise Service Bus most commonly known in the NHS as a Trust Integration Engine (TIE).

This implements as series of Enterprise Integration Patterns based around messaging; the diagrams below follow conventions used for these patterns.

The ESB has a Canonical Data Model which is expressed in this Implementation Guide using HL7 FHIR. This model is common to all the exchange formats used in the ESB:

• JSON HL7 FHIR
• pipe+hat HL7 v2
• potential use case for sharing reports: XML IHE XDS.b

Enterprise Data Contracts

Canonical Data Model

This canonical model is a mandatory extension to HL7 UK Core and includes requirements from

• NHS England HL7 v2 ADT Message Specification
• Digital Health and Care Wales - HL7 ORU_R01 2.5.1 Implementation Guide
• Royal College of Radiologist
• IHE Europe Metadata for exchange medical documents and images see UK content.
• NHS Data Model and Dictionary
• NHS Canonical Data Model

These are detailed in Data Contracts with standard-specific versions:

• HL7 FHIR (R4)
• HL7 v2 (2.5.1)
• IHE XDS

This canonical model is not specific to Genomics. It is focused on standard message construction patterns in particular CorrelationIdentifier such as Order Numbers and Episode/Stay Identifiers and use of Clinical Coding Systems such as UK SNOMED CT.

Genomic-Specific modeling, which this model supports, can be found on NHS England FHIR Genomics Implementation Guide

Enterprise Workflow Interactions

LAB-1 Data Model, inc CDM ServiceRequest

To support genomics workflow, this guide is aligned to enterprise workflow processes described in IHE Laboratory Testing Workflow, terminology from this guide especially around Actors is used throughout this Implementation Guide.

Security

See API Security