Authoring profiles by Michel Rutten

Authoring Profiles
Michel Rutten
FHIR Developer Days
November 25, 2014
© 2014 HL7 ® International. Licensed under Creative Commons. HL7 & Health Level Seven are registered trademarks of Health Level Seven International. Reg. U.S. TM Office.

Who am I?
 Name: Michel Rutten
 Company: Furore
 Background:
 Professional software developer since 1998
 Microsoft .NET; Healthcare industries
 Technical Specialist at Furore since May 2014
 Member of the Furore FHIR development team
 Lead developer of Forge
2

TOPICS

Presentation Topics
 Introduction
 Resources
 Profiles
 Representations
 Authoring Tools
 Authoring Profiles
 Metadata
 Structures
 Bindings
 Constraints
 Extensions
 Slicing
4

Introducing
PROFILES

The need for profiles
 Many different contexts in healthcare, but a
single set of Resources
 Need to be able to describe restrictions
based on use and context
 Allow for these usage statements to:
 Authored in a structured manner
 Published in a repository
 Used as the basis for validation, code, report and UI
generation.
17

Use of Profiles
Publish to
repository
Profile
Report
Implementation
guide
POCO
Validate
Resource
Conformance
statement
18

What is a profile?
 Special resource
 Statement of use of one or more FHIR
resources
 Provides additional rules about how a type of
resource is utilized in a particular context of use, or
for a particular use case
 Specify restrictions / constraints on resources
 Specify extensions on resources
19

Profiling a resource
Resource
Definition Patient
Profiled
Resource
My
Patient
20

21
“Must use only the Dutch national patient identifier”
“Need to register an administrative race code for a Patient in the
US”
“Patient Discharge documents must at least contain section
“Discharge Medication” and section “Discharge Diagnosis”
“In our Patient registration system, we use these maritalStatus
codes beyond those provided by HL7…”
“Our patient registration system, only supports having one single
name per Patient”

22
Demand that the identifier uses your
national patient identifier
Limit names to just 1 (instead of 0..*)
Limit maritalStatus to another set of
codes that extends the one from
HL7 international
Add an extension to support
“RaceCode”
Note: hardly any
mandatory elements in
the core spec!

Using profiles
 Formulate what exchanging partners must
adhere to
 Server & client may publish their
conformance to profile
 When communicating a resource, a resource
can indicate the profiles it conforms to.
 Receiving side may verify conformance
23

Tagging a resource
Patient
• MRN 31415
• “Michel Rutten”
• 20-01-1973
• Sittard
• “I’m a Patient conforming to the Dutch
Profile”
See http://hl7.nl/Profiles/patient-nl
24

Profile –a “normal”
resource
25 …computable!

Introducing profiles
REPRESENTATIONS

Formats
27
 XML
 Namespace: http://hl7.org/fhir
 Also includes XHTML
 JSON
 No namespaces…
 JSON XPath Navigator

Differential Structure
28
 Describes only modified elements
 Different from resource definition
 Does not describe default elements
 Identical to resource definition
 Targeted at profile authors
 Concise XML
 Focus on customizations

Example: Lipid
29

Snapshot
30
 Contains all resource elements
 Modified elements
 Default elements
 Targeted at profile tooling
 Easier to process programmatically

Example: Lipid
31

Expansion
32
 FHIR API supports the expansion of
differential profiles
 Tooling
 Open: Expand differential profile
 Save: Generate differential profile

Profile Authoring Tools
SPREADSHEET

Profile spreadsheet
 HL7 Wiki
 http://wiki.hl7.org/index.php?title=FHIR_Spreadsheet_Profile_Authoring
 Tab page ↔ resource
 Row ↔ resource element
 Column ↔ element property
34

Example: Lipid
35

Profile spreadsheet
 Supports differential structures
 Only include rows for modified elements
 Supports snapshots
 May include default elements by copying rows
form resource definition sheet
36

Profile Authoring Tools
FORGE

Forge
 FHIR Profile Editor
 http://fhir.furore.com/forge
 Windows Desktop Application
 Supports online & offline use
 Load from / save to FHIR server
 Load from / save to disk
38

Forge
 Implementation based on FHIR API
 Resource definitions
 Deserialize XML to POCO
 Serialize POCO to XML
 Profile error validation
 Supports differential and snapshot structures
 Open differential/snapshot profile
 Generates compressed XML
39

Work In Progress
 Current release supports most of DSTU 1
 Some advanced features are not yet
supported, e.g.
 Type slicing (value[x])
 Search parameters
 Some bugs...
40

Example: Lipid
41

Authoring Profiles
STEP BY STEP

Running Example
 “Lipid Profile” example from spec
 http://www.hl7.org/implement/standards/fhir/diagno
sticreport-profile-lipids.html
 DiagnosticReport containing 4 results:
 1x Cholesterol
 1x Triglyceride
 1x HDL Cholesterol
 0/1x LDL Cholesterol
 Package it up in a message
44

Authoring Profiles
METADATA

Identification
 REST Id on server
 http://spark.furore.com/fhir/profile/lipid.v1
 Server assigned
 Name
 “Lipid Profile”
 Human readable
 Author assigned
46

Identification
 Identifier
 Globally unique
 Author assigned
 UUID: 15046b9c-2da0-4b80-82ef-c6af6fcfd2bf
 OID: 2.16.840.1.113883.10.20.2.1
 URN
 urn:openEHR.org:EHR-ACTION.medication.v1
 http://hl7.org/fhir/Profiles/iso-21090-2011
47

Versioning
 We used semantic versioning
 Uses “<major>.<minor>.<patch>”
 See semver.org
 Major version number is increased on
breaking changes
 Major version number is part of author-assigned
identifier AND REST url
 Both versions may co-exist on server, they
have different URLs and names
48

Versioning example
URL Id v
http://fhir.nl/Profile/patient.v1 urn:fhir.nl:profile:patient:v1 1.0.0 Original
version
http://fhir.nl/Profile/patient.v1 urn:fhir.nl:profile:patient:v1 1.0.1 Typo
Clarification
Correction
Bugfix
http://fhir.nl/Profile/patient.v1 urn:fhir.nl:profile:patient:v1 1.1.0 Non-breaking
change
Addition
http://fhir.nl/Profile/patient.v2 urn:fhir.nl:profile:patient:v2 2.0.0 Breaking
change
49

Profile Metadata
Publisher
• Organization or individual
responsible for publishing
• Should be populated
• e.g. “FHIR Project Team“
Telecom
• One or more contact points
of the publisher
• Telephone, email, website
etc.
Description
• Longer description of the
contents of the profile
Code
• One or more coded
descriptions to help with
finding the profile
• e.g. LOINC 58239-5 (lipid)
Status
• Draft, Active, Retired
• Experimental Y/N
Requirements
• Scope & Usage
• The “need” or “why” of the
profile
Date
• Of publication
• YYY-MM-DD
• e.g. “2013-07-07"
50

Example
51

Authoring Profiles
STRUCTURES

What’s in a profile?
53
Metadata
Extensions
Constrained
Resources
& Datatypes
Profile

Structures
54
 Profiles contain “Structures”
 Set of constraints on (nested) elements of a
Resource or Datatype
 “Subclass” of a Resource, with specific limits
on its elements
 Cardinality
 Value domains
 Invariants

Example
55
“Cholesterol observation” is an Observation :
 That has a fixed LOINC code 35200-5 (Cholesterol) as its
name
 Has a quantity as value that’s expressed in mmol/L (a
UCUM unit) (without a ‘comparator’) OR ELSE there’s a
comment
 An interpretation limited to LL,L,N,H,HH
 A “recommended” high reference range of 4.5 (no low)
mmol/L, independent of age (no age)
 Is an independent observation (no related)

Cardinality
 Number of elements in a set
 0 - None
 1 – Single element
 N – N elements
 * – Many elements
 Multiplicity
 Minimum cardinality
 Maximum cardinality
56

Cardinality
Minimum Maximum Description
0 0 Prohibited / removed element
0 1 Optional single element
0 * Zero or more elements
1 1 Required element
1 * One or more elements
2 3 Specific bounds
57

Constrain Cardinality
58
 You can only further restrict the cardinality of
resource elements
 Increase minimum cardinality
 Decrease maximum cardinality
 An element that is mandatory in the resource
definition cannot be constrained as optional

Limit value domains
59
AddressNL
OrganizationNL
=“true”
Only allow “active” Patients
If deceased is given, it must be
a dateTime, not a boolean
Use a profiled datatype (from
this or other profile)
Only allow reference to a
profiled resource

Contextualize Narrative
60
Override the base spec’s descriptions by
adding context specific narrative:
 short : string 1..1
 formal : string 1..1
 comments : string 0..1
 requirements : string 0..1
 synonym : string 0..*
 example[x] : 0..1 (example value!)
 mappings : 0..* (more specific mappings)

Example: spreadsheet
61

Example: Forge
62

Demo: Forge
63
0..1
“if no value…”
= ‘ok’
1..1
1..1

Must support?
64
 Authors: SHALL be capable of providing a
value for the element and resource
 Consumers: SHALL be capable of extracting
and doing something useful with the data
element.
 "Something useful" is context dependent.
The Profile SHALL describe what it means
for applications to “support” the element

Reusable constraints
65
 We have multiple components within the
“Lipid Profile” with Quantity
 All with the same constraints
 Units are mmol/L
 in UCUM (http://unitsofmeasure.org)
 no comparator
 Let us first make a reusable “lipid quantity”
constraint on the Quantity datatype!

Demo: Lipid Quantity
66
Element Property Value
Quantity Short Quantity as used in lipid measurements
Quantity Formal Quantity as used in lipid measurements
Quantity Comments Lipid measurements are expressed in
mmol/L
Quantity.units Fixed value mmol/L
Quantity.system Fixed value http://unitsofmeasure.org/
Quantity.code Fixed value mmol/L

Demo: Lipid Quantity
67

Authoring Profiles
BINDINGS

Coded types
69
In a Profile, we may want to limit the codes that can possibly be used in
coded elements in the Resources
Codes are defined
in code systems

CodeSystem vs.
ValueSet
70
“Code System”
“ValueSet”
“Dante’s deadly sins”
Pride
Envy
Wrath
Sloth
Avarice
Gluttony
Lust
Takes concepts from…
Defintion of
terms
An enumeration
of terms
Example: SNOMED-CT Example: “Childhood diseases”

Identification of
CodeSystems
 If you refer to CodeSystems, you use a URL
(instead of OID in v2 and v3):
 http://snomed.info/sct
 http://loinc.org
 http://hl7.org/fhir/sid/icd-10
 We have introduced them for v2 and v3:
 http://hl7.org/fhir/v2/0078
 http://hl7.org/fhir/v3/ActClass
71

ValueSet
 Has metadata
 much like Profile: identifier, version, name, etc
 Is built by inclusion of terms from
CodeSystems
 Can exclude specific codes from other
valuesets
 Can import codes from other ValueSets
72

ValueSet
73
In/exclude concepts
Metadata

ValueSet
But it can also enumerate (and so indirectly
define) all concepts for a new codesystem:
 A ValueSet has metadata (much like Profile:
identifier, version, name, etc)
 A ValueSet is built by defining terms from
and for a new CodeSystem
 These new concepts have a display label
and a definition
 …and may be hierarchically organized 74

ValueSet
75

ValueSet: Gender
76

Bindings
 When used in a Resource, the modelers
include Bindings
 Bindings specify which codes can be used
77

Example: Forge
78

Conformance
79
If implementers of your profile provide a
different code than you have in your profile….
isExtensible=N isExtensible=Y
Required SHALL Validation error
Non-conformant
Additional codes
allowed
Preferred SHOULD Validation error
Discouraged
Supplemental
codes likely
Alternatives
allowed
Example MAY Just a suggestion, no preference

Authoring Profiles
FORMAL CONSTRAINTS

Formal constraints
 Examples:
 “If a Cholesterol value result is not available, use
the comments field”
 “A patient’s birthdate must be on or before today’s
date”
 May concern a single element, or cover
multiple elements.

Formal constraints
 Uses free text (human) + xpath (executable)
 Constraints should be declared on lowest
element in the hierarchy that is common to
all nodes referenced by the constraint.
 Identified by (local) ‘Key’
 Involved elements refer to that id
 Specify severity
 “error” or “warning”

Context of a constraint
83
“If a Cholesterol value result is not available, use the comments field”
• This constraint is on the
elements “valueQuantity” and
“comments”
• We would have to formulate this
constraint on the Observation,
this is the context of the
constraint
• We assign the constraint a “key”
value that’s unique within the
Observations’ constraints
• We refer from both “value[x]”
and “comments” to this “key”.
This means: if my value
changes -> revalidate the
constraint

Example: Forge
84

Example: Forge
85

Example: Forge
86

Authoring Profiles
EXTENSIONS

Extensions
 Extension Definition
 Global, shared
 Extension Reference
 Structure element
 References an Extension Definition
88

Extension Context
 An extension has a context type
 Resource, Datatype, Extension, Mapping
 And a context path
 (Resource) Observation
 “The observation was calculated”
 (Resource) Observation.value
 “The observation’s ‘value’ was calculated”
 (Datatype) Quantity
 “This quantity was calculated”
(any Quantity used in any resource!) 89

Extension Definition
90
Note: multiple
contexts!

Extending a name
91
Key = location of formal definition
Value = value according to definition

Calculated - Definition
92

Calculated - Use
93

Authoring Profiles
SLICING

Slicing
 Slicing Group
 Discriminator
 Cardinality
 Slice
 Cardinality within the group
 Additional constraints

Example: Contact
 Resource definition is very generic:
 Telecom
 Contact { phone, fax, email, url } (0-*)
 Let’s constrain; require phone & email:
 Telecom (2)
 Phone (1)
 Email (1)
 Discriminator = system
96

Slice Cardinality
97
Slice Group Cardinality Slice Cardinality
Telecom 2…2 Phone 1…1
Email 1…1
Must specify both Phone and Email
Email 0…1
Must specify Phone and/or Email
Email 0…1
Optional Phone and/or Email

Example: Contact
98

Example: Lipid
99

Example: Lipid
100

Forge
FUTURE DEVELOPMENT

Profile Validation
 User friendly validation error messages
 Validation error message provided by API…
 Highlight invalid controls
 Red border
 Click on message => focus associated control
 Support for XPath validation rules…
 Hard-coded subset?
102

Resource Validation
 Validate a resource against the profile
 Generate validation report
 List discrepancies
103

Value Slicing
 Slice value[x] element
 Slice element for each included type
 Automatically generate/synchronize slices
 Cf. regular slice – all slices share a common
type
 Example
 Schedule OR Period
104

Modifier Extensions
 Extension with isModifier = True
 Slicing within ModifierExtensions collection
 Instead of regular Extensions collection
 Issue:
 If a profile is updated by clearing the isModifier
property value, then all related profile definitions
become invalid…
105

Authoring profiles by Michel Rutten

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