Terminology and HL7Terminology and HL7

Dr Colin PriceDr Colin Price

HL7 UK11th December 2003

Since 1992, the NHS has had a Since 1992, the NHS has had a strategic commitment to using a strategic commitment to using a

singlesingle comprehensive comprehensive terminology to support patient terminology to support patient

care.care.

High level implementation goalsHigh level implementation goals

Nation-wide roll out Multi-purpose use

Direct and indirect care Multi-professional uptake

Doctors, nurses, allied health Multiple environments

Primary care, hospitals, community Extensibility

Patient access, Social care.

Information for Health; Building the Information Core;

Delivering 21st Century IT

NHS requirements as a “customer"NHS requirements as a “customer"

A single comprehensive scheme Nationally licensed Able to support key NHS functions Flexible and dynamic With robust cross maps to classifications Allowing NHS input into governance

Editorial processes Business management

And …. available now To support roll out within National Programme.

790.12 SNOMED CT

All new systems shall support the SNOMED CT standard.All existing systems should support SNOMED CT.

790.13 UKCPRS

All new systems shall support the UKCPRS standard.All existing systems should support UKCPRS.

ICRS OBS3 Final 1.0

SNOMED CT developmentSNOMED CT development

April 1999

April 2003

April 2000

April 2001

Agreement signed

Read/SNOMED merger SNOMED CT design

Formative Evaluation.Start-up

April 2002

Release 1 January

2002

Alphatest

April 2004

ImplementationFoundation.

Evaluation & Testing

Core Refinement.

DraftStandard

Milestones to dateMilestones to date

January 2002 Read Codes and SNOMED merger completed

From 2002 Early adopter US implementations of SNOMED CT

April 2003 NHS Formative Evaluation Programme completed

April 2003 NHS end user licensing

August 2003 Approval as draft fundamental standard for NHS.

Key Objectives 2003 - 2004Key Objectives 2003 - 2004

Systematic refinement of SNOMED core Based on agreed priorities and use cases

Development and testing of UK specifics Extensions, subsets, cross maps etc Based on requirements of National Programme for IT

Support for UK implementations Planning migration of primary care Read Code systems Validation of cross maps to ICD10 and OPCS4 Testing and evaluation in real systems

Terminology service development.

Key Objectives 2003 - 2004Key Objectives 2003 - 2004

Systematic refinement of SNOMED core Based on agreed priorities and use cases

Development and testing of UK specifics Extensions, subsets, cross maps etc Based on requirements of National Programme for IT

Support for UK implementations Planning migration of primary care Read Code systems Validation of cross maps to ICD10 and OPCS4 Testing and evaluation in real systems

Terminology service development.

Clinical databases (Read Codes and other schemes) Applications Reports Protocols Decision support algorithms Preserving integration with other semantic

components.

The migration challengeThe migration challenge

Servicing local requirements Servicing local requirements

Local subsets Local navigation hierarchies Cross mappings to local classifications Local sub-licensing & distribution mechanisms Local education and training Local integration with other standards Local migration of legacy data & systems.

Summary Summary

SNOMED CT is the terminology of choice for the NHS Strategic direction ISB approval as draft fundamental standard ICRS OBS specification

Good progress on developing local enhancements for the UK

Active work to support NPfIT requirements Integration with other standards e.g .messaging Format of NHS Drugs and Devices Dictionary (UKCPRS)

Implementation issues being investigated: Migration of primary care systems Education, training, change management.

Terminology and HL7Terminology and HL7

Dr Colin PriceDr Colin Price

HL7 UK11th December 2003

Terminology and HL7 UKTerminology and HL7 UK

David MarkwellThe Clinical Information Consultancy

Chair of HL7 UK

Member of the HL7 Vocabulary Technical Committee

Consultant to the SNOMED International Editorial Board

Vocabulary in HL7 Version 3Vocabulary in HL7 Version 3OverviewOverview

Structural Vocabulary Coded Data Types Vocabulary Domains Vocabulary Specific Standards Vocabulary Localisation Rules HL7 Version 3 with SNOMED CT

Structural Vocabulary Structural Vocabulary

The HL7 Reference Information Model provides the shared structure that underpins all HL7 Version 3 Standards

Structural Vocabulary Internal codes that name specialised classes without modifying the

structure Part of the standard – not open to localisation

For example “OBS” designates an act of “observation”

As distinct from a procedure, supply, etc. “PSN” designates an entity that is a “person”

As distinct from an organisation, device, etc.

Coded data typesCoded data types HL7 Version 3 specifies a rich set of data types and standardises how

these are to be expressed (e.g. in XML) Four coded data types which meet different requirements

Coded Simple Just the code

Coded Value Code + Code system identifier + Readable descriptions (“originalText” and “displayText”)

Coded with Equivalents Coded Value + optional translations expressed in other code systems

Concept Descriptor Code Value + optional qualifiers + optional translations

Vocabulary domainsVocabulary domains Every coded attribute in an HL7 standard has a “Vocabulary

Domain” This identifies the range or meanings to be represented by a code

value in that attribute Vocabulary Domains can be refined for each message type

In a message coded attributes are populated with codes from a “Value Set” This is a set of codes from a specified source that represent the

“Vocabulary Domain” in a given realm The Value Sets are taken from “Code Systems”

Internal HL7 Code Systems Usually fairly limited and specific to particular domain

External Code Systems Usually referenced to populate broader domains Examples include SNOMED CT and the Read Codes

Vocabulary specific standardisationVocabulary specific standardisation

Register of Code Systems Maintained by HL7 Allocates of unique “OID” to each code system Allows code systems to be recognised in messages Register is available at www.hl7.org in text and XML

Common Terminology Server Proposed standard API for vocabulary functions required to enable

use of a variety of code systems in HL7 standards and messages Guide on good practices for code systems

Non-reuse of codes / concept permanence Meaningless identifiers Effective and regular maintenance

Localisation and Vocabulary in HL7Localisation and Vocabulary in HL7

There are HL7 International Affiliate organisation in nearly 30 countries

HL7 recognises the need for a common global standard that meets local needs

Countries vary in their use of code systems Some have billing arrangements, policies or even laws that require

particular code systems HL7 Vocabulary Technical Committee has taken a lead in

realising the idea of localisation Localisation is now a normative part of the HL7 Version 3

standard

HL7 Version 3 with SNOMED CTHL7 Version 3 with SNOMED CT

HL7 Version 3 is a family of standards Providing a framework for development of consistent, requirements-

based communication specifications Based on a reference information model that offers a consistent

grammar for clinical expressions but does attempt to mandate a single code system

SNOMED CT is a controlled terminology Covering the same broad scope as HL7 Able to populate HL7v3 coded attributes to represent and

communicate detailed semantics Has logical definitions that permit effective retrieval Has a subset mechanism that facilitates definitions of value sets for

HL7v3 messages

Vocabulary in HL7 Version 3Vocabulary in HL7 Version 3 A summary of the key pointsA summary of the key points

HL7 Structural Vocabulary Act as semantic ligaments holding the V3 skeleton together and

providing constrained flexibility HL7 Coded Data Types

Unambiguously carry coded information expressed using any registered vocabulary or code system

HL7 Vocabulary Domains Express the semantic space to be filled by coded attributes to enable

meaningful interoperability HL7 Vocabulary Specific Standards

Support more effective use coding in healthcare HL7 Vocabulary Localisation Rules

Meet national needs within a global standard