FHIR standard reference

The Validated Relationships Service (VRS) implements the HL7 FHIR R4 (Release 4) specification with conformance to the UK Core FHIR Implementation Guide. This document outlines the standards foundation and conformance requirements.

HL7 FHIR R4 Specification

What is FHIR?

FHIR (Fast Healthcare Interoperability Resources) is a standard for exchanging healthcare information electronically. It combines the best features of HL7's previous standards (v2, v3, CDA) with modern web technologies.

Version information

Specification	Version
HL7 FHIR	R4 (4.0.1)
Publication Date	2019-10-30
Specification URL	https://hl7.org/fhir/R4/

Core concepts

Resources

FHIR defines healthcare data as Resources - discrete units of exchangeable data. The NHS Health Check online uses the following resource types:

Resource	UK Core / FHIR Spec Link	Purpose
Bundle	https://hl7.org/fhir/R4/bundle.html	Container for multiple resources
Consent	https://hl7.org/fhir/R4/consent.html	Core representation of a proxy role
Patient	https://simplifier.net/hl7fhirukcorer4/ukcore-patient	Patient demographics
RelatedPerson	https://simplifier.net/hl7fhirukcorer4/ukcore-relatedperson	Uni-directional relationship between a proxy and patient
QuestionnaireResponse	https://hl7.org/fhir/R4/questionnaireresponse.html	Answers provided by users to support digital applications for proxy access

Data types

Common FHIR data types used in this implementation:

Data Type	Description	Example
Identifier	Logical identifier for a resource	NHS Number
code	A value that is taken from a set of controlled strings	active status
CodeableConcept	Coded value with text	Relationship code + display
Coding	Single code from a terminology	{ system, code, display }
dateTime	Date and time	2025-01-14T10:30:00+00:00
Period	Time range where both start and end are inclusive	{ start, end }

Cross-versioning

In delivering the service we have needed to "backport" certain properties from R5 to the R4 Consent resource profile. These properties have been added as extensions to our R4 profile. The extensions are available in FHIR Cross-Version Extensions package for FHIR R4 from FHIR R5 - Version 0.0.1-snapshot-2. See the Directory of published versions. Specifically the following extensions have been referenced:

• grantor (Cross-version Extension for R5.Consent.grantor for use in FHIR R4)

UK Core FHIR Implementation Guide

Overview

UK Core is the NHS England endorsed FHIR implementation guide that defines UK-specific profiles, extensions, and value sets. It ensures consistent FHIR implementations across the UK healthcare system.

Version information

Specification	Version	Status
UK Core	STU3 (3.0.0)	Standard for Trial Use
Base Specification	FHIR R4
Simplifier URL	https://simplifier.net/HL7FHIRUKCoreR4
Implementation Guide	https://simplifier.net/guide/uk-core-implementation-guide-stu3-sequence

Required vs optional

Cardinality	Meaning
1..1	Required, exactly one
0..1	Optional, at most one
0..*	Optional, any number
1..*	Required, at least one