Transcript Validation of a European Message Standard for Electronic

XML used for Healthcare
Messaging and Electronic
Health Record Communication
David Markwell - Clinical Information Consultancy
Andrew Hinchley
Communication Planning Ltd
Three intertwined projects
 CEN TC251 Healthcare Informatics Standards


ENV13606 - Prestandard for EHCR Communication
Part 4 - Messages for exchange of information
 XML-EDI Project - using XML for EDI

EU Information Society Initiative for Standardisation
(ISIS)
 XMLEPR Project - validation of the message

UK National Health Service and
Royal College of General Practitioners
Three parallel objectives
 A standard message for health record
transfer
 Investigate XML as a syntax for EDI
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
Propose good practice guidelines for XML/EDI
Identify benefits & issues raised by XML/EDI
 Validation of a draft of ENV13606



Confirm it meets UK NHS needs for GP to GP
transfer of patient records
Propose revisions where needed to meet needs
Identify needs for implementation guidelines
Background to healthcare record
messages in the XML/EDI project
Background
EHCR Communication Prestandards
 Part 1 - Extended Architecture

A Standardised view of EHCR information
 Part 2 -Term List

High-level categories & annotations
 Part 3 - Distribution Rules

A Standard way to express access rules
 Part 4 - Messages

Standard messages for EHCR communication
CEN TC251 Message Development
Method
Scope
Specification
User
requirements
Scenarios
Content Dependent
Domain Information
Model
Communication
roles & services
General
Message Description
Hierarchical
GMD
Syntax
Implementable
Message
Specification
Proposed EHCR
message data items
plain text
structured coded
quantifiable observation
medication
physical entity reference
record
component
a type of
data item
external data reference
event
person identifier
person name
language
address
telecom
patient related party
related location
community defined
EHCR
message
EHCR message structure
1
folder
EHCR extract
contains 1
1..*
specialised as
original
component
complex
1..*
record
component
specialised as
link item
data item
composition
headed
section
cluster
Coding, terminology &
semantics
 Present healthcare data structures


Allow use of a variety of coding schemes
ENV13606 Part 2 Term List provides a minimum
set of heading context terms
 Improved communication requires


Standard terms, qualifiers and classifications
Mapping between terms and classifications
 An interesting development

Merger between the UK NHS Clinical Terms
(Read Codes) and SNOMED-RT
Background
HTML & XML -- Chalk & Cheese
 Is XML extended HTML?


 But

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
Both based on SGML
Both contain tags
 Is cheese extended chalk?


 But
HTML is a layout
mark-up format
XML represents data
HTML uses fixed tags
XML enables tags to be
purpose-defined




Both are edible solids
Both contain calcium
Chalk is good for display
Cheese is nourishing
Chalk is hard
Cheese soft or resilient
Mapping from UML models of
messages to XML
Mapping message models for
implementation
 Mapping to EDIFACT


Difficult manual process
Conformance to models unverifiable
 Mapping to XML





Automatable process
Preserves structure of model
Verifiable conformance
Easier profiling
Opportunity for ISO led convergence with HL7
Mapping - General Points
 Message Development Methods lead to
syntax independent models
 Limits of automation


Extra information needed in models to support
maps
UML may not be rich enough!
 Retain links back to the model
Mapping messages or models
 XML to represent UML models


generalised DTD possible
content represents classes & relationships
 XML to represent information storage

Freer use of XML cross-references (e.g. ID &
IDREF)
 Messaging environment
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
some relationships by nested containment
others refer to instance Ids not in message
Mapping classes
 Concrete classes

Mapped to XML-Elements
 Abstract (generalised) classes


Represented as XML-Entities
Add to the content model
• In XML-Elements for classes specialised from them

Create a choice structure for specialisations
• In XML-Elements that include the generalisation
Mapping attributes
 Most attributes mapped to an appropriate
XML-Element
 Attributes mapped to XML-Attributes
include

Metadata such as:
• Coding scheme identifier for a code value
• The language of the content (xml:lang)



Status or typing data that affects processing
Possibly for unique IDs ("ID" & "IDREF”)
Enumerated data types (pragmatic reasons)
Mapping common classes
 Common Class XML-Element

Example:
• “PersonName" in "PatientMatchingInfo”
OR
 XML-Element specific to each attribute
with derived content

Example:
• "AlternativeName" in "PatientMatchingInfo”
Mapping to DTDs or XML Schema
 Mapping to DTDs now because they are:


Stable
Well supported by software
 Schema proposals offer major advantages
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More flexible constraints
Data Typing
Archetypes
Extensibility
 Mapping to Schemas next logical step
XML/EDI in use to validate the
healthcare record message for UK
GP to GP communication
Background to XMLEPR
UK NHS GP computing
 The situation

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95% of UK GPs have computers
50% use these computers for clinical patient
records
 GP computer systems in the UK
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Three major suppliers of GP systems
Twelve widely used systems or versions
Different record structures
 None transfer records when patients move
Clinical validation
 What is clinical validation of a message?

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Suppliers of diverse systems map real record from
their systems into the message structure
Clinical professionals review original records and
the messages generated
Look for inconsistencies, missing or added info.
Determine whether the representations are “safe”
 XML used for validation because it offered


Direct mapping from message models
Freely available viewers and software libraries
The validation process
Compare &
Comment
Observe
GP system
Clinicians
Viewer
PT29 Provide EHCR
Message
Mapping
Experts
Export
Provide EHCR
DTD
Layout
Instance of XML
message/document
Comment and resolution
EHCR information
Specifications and rules
XMLEPR project
Validation of GP to GP communication
 Supplier results

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Four leading GP system suppliers populated the
messages with information from their systems
Found XML learning-curve/implementation
easier than EDIFACT
 Viewers used for clinical validation
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IE5
XML-Notepad
Specialised viewer developed in the project
Results of validation
 The Provide EHCR message is substantially able to
convey the information present in a majority of
existing GP Electronic Patient Records (in the UK)
 Some weaknesses in the draft message proposal


Reported as formal comments to the Project Team
responsible for the draft prestandard
All these comments were accepted and resulted either in
changes to the message or clarifications in the
documentation
 Further validation, piloting and implementation
recommended to the UK NHS
Other results and progress
 EHCR Communication Prestandards


Accepted by ballot on 29 June 1999
Comments from use will be monitored for the next
revision in 2-3 years time
 ISIS XML/EDI project continues to end of year
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Further recommendations and demonstrations expected
 ISO TC215 Health Informatics

May draft guidelines for use of XML in messaging
References
 Material about the message and links to other
sites

http://www.clinical-info.co.uk
 CEN TC251 Standards including ENV13606

http://www.centc251.org
 XMLEPR project

http://www.CommunicationsPlanning.co.uk/infopages
 Other XML/EDI information

http://www.tieke.fi/isis-xmledi
Healthcare uses of XML
User Interface
Enter
User Interface
View
View
Application
Read
Data store
EDI Interface
Application
EDI Interface
Write
Enter
Messages in XML
Messages in XML
Read
Write
Data store
User Interface
Enter
View
Application
Write
Browser
API
User Interface
View
Enter
Application
Read
Data store
Read
Write
Data store
Browser
API
User Interface
View
Enter
Application
Read
Data store
Data
store
Write
Data store
Browser
API
User Interface
View
Enter
Application
Read
Write
Data store
User Interface
Enter
Browser
View
API
Application
Write
User Interface
View
Enter
Read
Write
Application
Read
Data store
XML
Archive
Data store
XML
User Interface
Enter
View
Application
Write
Browser
API
User Interface
View
Enter
Application
Read
Data store as
XML documents
Read
Write
Data store
User Interface
Enter
User Interface
View
Application
Write
View
Enter
Application
Read
Data store as
XML documents
Read
Write
References
 Material about the message and links to other
sites

http://www.clinical-info.co.uk
 CEN TC251 Standards including ENV13606

http://www.centc251.org
 XMLEPR project

http://www.CommunicationsPlanning.co.uk/infopages
 Other XML/EDI information

http://www.tieke.fi/isis-xmledi