Operation
Definition
<?xml version="1.0" encoding="UTF-8"?>
The definition of a value set is used to create a simple collection of codes suitable
for use for data entry or validation.
If the operation is not called at the instance level, one of the in parameters url, context
or valueSet must be provided. An expanded value set will be returned, or an OperationOutcome
with an error message.
A canonical reference to a value set. The server must know the value set (e.g. it is defined
explicitly in the server's value sets, or it is defined implicitly by some code system
known to the server
The value set is provided directly as part of the request. Servers may choose not to accept
value sets in this fashion
The identifier that is used to identify a specific version of the value set to be used
when generating the expansion. This is an arbitrary value managed by the value set author
and is not expected to be globally unique. For example, it might be a timestamp (e.g.
yyyymmdd) if a managed version is not available.
The context of the value set, so that the server can resolve this to a value set to expand.
The recommended format for this URI is [Structure Definition URL]#[name or path into structure
definition] e.g. http://hl7.org/fhir/StructureDefinition/observation-hspc-height-hspcheight#Observat
ion.interpretation. Other forms may be used but are not defined. This form is only usable
if the terminology server also has access to the conformance registry that the server
is using, but can be used to delegate the mapping from an application context to a binding
at run-time
The purpose is to inform the server whether to use the value set associated with the context
for reading or writing purposes (note: for most elements, this is the same value set,
but there are a few elements where the reading and writing value sets are different)
A text filter that is applied to restrict the codes that are returned (this is useful
in a UI context). The interpretation of this is delegated to the server in order to allow
to determine the most optimal search approach for the context. The server can document
the way this parameter works in
..expansion.textFilter. Typical usage of this parameter includes functionality like:
Text Search engines such as Lucene or Solr, long with their considerable functionality,
might also be used. The optional text search might also be code system specific, and servers
might have different implementations for different code systems
The date for which the expansion should be generated. if a date is provided, it means
that the server should use the value set / code system definitions as they were on the
given date, or return an error if this is not possible. Normally, the date is the current
conditions (which is the default value) but under some circumstances, systems need to
generate an expansion as it would have been in the past. A typical example of this would
be where code selection is constrained to the set of codes that were available when the
patient was treated, not when the record is being edited. Note that which date is appropriate
is a matter for implementation policy.
Paging support - where to start if a subset is desired (default = 0). Offset is number
of records (not number of pages)
Paging support - how many codes should be provided in a partial page view. Paging only
applies to flat expansions - servers ignore paging if the expansion is not flat. If count
= 0, the client is asking how large the expansion is. Servers SHOULD honor this request
for hierarchical expansions as well, and simply return the overall count
A
that specifies a system+code that is either a use or a language. Designations that match
by language or use are included in the expansion. If no designation is specified, it is
at the server discretion which designations to return
Controls whether inactive concepts are included or excluded in value set expansions. Note
that if the value set explicitly specifies that inactive codes are included, this parameter
can still remove them from a specific expansion, but this parameter cannot include them
if the value set excludes them
Controls whether or not the value set expansion nests codes or not (i.e. ValueSet.expansion.contains
.contains)
Controls whether or not the value set expansion is assembled for a user interface use
or not. Value sets intended for User Interface might include
or have nested contains with items with no code or abstract = true, with the sole purpose
of helping a user navigate through the list efficiently, where as a value set not generated
for UI use might be flat, and only contain the selectable codes in the value set. The
exact implications of 'for UI' depend on the code system, and what properties it exposes
for a terminology server to use. In the FHIR Specification itself, the value set expansions
are generated with excludeNotForUI = false, and the expansions used when generated schema
/ code etc, or performing validation, are all excludeNotForUI = true.
Specifies the language to be used for description in the expansions i.e. the language
to be used for ValueSet.expansion.contains.display
Code system, or a particular version of a code system to be excluded from the value set
expansion. The format is the same as a canonical URL: [system]|[version] - e.g. http://loinc.org|2.5
6
Specifies a version to use for a system, if the value set does not specify which one to
use. The format is the same as a canonical URL: [system]|[version] - e.g. http://loinc.org|2.56
Edge Case: Specifies a version to use for a system. If a value set specifies a different
version, an error is returned instead of the expansion. The format is the same as a canonical
URL: [system]|[version] - e.g. http://loinc.org|2.56
Edge Case: Specifies a version to use for a system. This parameter overrides any specified
version in the value set (and any it depends on). The format is the same as a canonical
URL: [system]|[version] - e.g. http://loinc.org|2.56. Note that this has obvious safety
issues, in that it may result in a value set expansion giving a different list of codes
that is both wrong and unsafe, and implementers should only use this capability reluctantly.
It primarily exists to deal with situations where specifications have fallen into decay
as time passes. If the value is override, the version used SHALL explicitly be represented
in the expansion parameters
The result of the expansion. Servers generating expansions SHOULD ensure that all the
parameters that affect the contents of the expansion are recorded in the ValueSet.expansion.paramete
r list
The value set expansion returned by this query should be treated as a transient result
that will change over time (whether it does or not depends on how the value set is specified),
so applications should repeat the operation each time the value set is used.
If the expansion is too large (at the discretion of the server), the server MAY return
an error (OperationOutcome with code too-costly). Clients can work through large flat
expansions in a set of pages (partial views of the full expansion) instead of just getting
the full expansion in a single exchange by using offset and count parameters, or use the
count parameter to request a subset of the expansion for limited purposes. Servers are
not obliged to support paging, but if they do, SHALL support both the offset and count
parameters. Hierarchical expansions are not subject to paging and servers simply return
the entire expansion.
Different servers may return different results from expanding a value set for the following
reasons:
The underlying code systems are different (e.g. different versions, possibly with different
defined behavior)
Servers introduce arbitrary groups to assist a user to navigate the lists based either
on extensions in the definition, or additional knowledge available to the server
When a server cannot correctly expand a value set because it does not fully understand
the code systems (e.g. it has the wrong version, or incomplete definitions) then it SHALL
return an error. If the value set itself is unbounded due to the inclusion of post-coordinated
value sets (e.g. SNOMED CT, UCUM), then the extension
can be used to indicate that the expansion is incomplete
The definition of a value set is used to create a simple collection of codes suitable
for use for data entry or validation.
If the operation is not called at the instance level, one of the in parameters url, context
or valueSet must be provided. An expanded value set will be returned, or an OperationOutcome
with an error message.
The value set expansion returned by this query should be treated as a transient result
that will change over time (whether it does or not depends on how the value set is specified),
so applications should repeat the operation each time the value set is used.
If the expansion is too large (at the discretion of the server), the server MAY return
an error (OperationOutcome with code too-costly). Clients can work through large flat
expansions in a set of pages (partial views of the full expansion) instead of just getting
the full expansion in a single exchange by using offset and count parameters, or use the
count parameter to request a subset of the expansion for limited purposes. Servers are
not obliged to support paging, but if they do, SHALL support both the offset and count
parameters. Hierarchical expansions are not subject to paging and servers simply return
the entire expansion.
Different servers may return different results from expanding a value set for the following
reasons:
* The underlying code systems are different (e.g. different versions, possibly with different
defined behavior)
* The server optimizes filter includes differently, such as sorting by code frequency
* Servers introduce arbitrary groups to assist a user to navigate the lists based either
on extensions in the definition, or additional knowledge available to the server
When a server cannot correctly expand a value set because it does not fully understand
the code systems (e.g. it has the wrong version, or incomplete definitions) then it SHALL
return an error. If the value set itself is unbounded due to the inclusion of post-coordinated
value sets (e.g. SNOMED CT, UCUM), then the extension [http://hl7.org/fhir/StructureDefinition/value
set-unclosed](extension-valueset-unclosed.html) can be used to indicate that the expansion
is incomplete
A canonical reference to a value set. The server must know the value set (e.g. it is defined
explicitly in the server's value sets, or it is defined implicitly by some code system
known to the server
The value set is provided directly as part of the request. Servers may choose not to accept
value sets in this fashion
The identifier that is used to identify a specific version of the value set to be used
when generating the expansion. This is an arbitrary value managed by the value set author
and is not expected to be globally unique. For example, it might be a timestamp (e.g.
yyyymmdd) if a managed version is not available.
The context of the value set, so that the server can resolve this to a value set to expand.
The recommended format for this URI is [Structure Definition URL]#[name or path into structure
definition] e.g. http://hl7.org/fhir/StructureDefinition/observation-hspc-height-hspcheight#Observat
ion.interpretation. Other forms may be used but are not defined. This form is only usable
if the terminology server also has access to the conformance registry that the server
is using, but can be used to delegate the mapping from an application context to a binding
at run-time
If a context is provided, a context direction may also be provided. Valid values are:
* 'incoming': the codes a client can use for PUT/POST operations, and
* 'outgoing', the codes a client might receive from the server.
The purpose is to inform the server whether to use the value set associated with the context
for reading or writing purposes (note: for most elements, this is the same value set,
but there are a few elements where the reading and writing value sets are different)
A text filter that is applied to restrict the codes that are returned (this is useful
in a UI context). The interpretation of this is delegated to the server in order to allow
to determine the most optimal search approach for the context. The server can document
the way this parameter works in [TerminologyCapabilities](terminologycapabilities.html)..expansion.t
extFilter. Typical usage of this parameter includes functionality like:
* using left matching e.g. "acut ast"
* allowing for wild cards such as %, &, ?
* searching on definition as well as display(s)
* allowing for search conditions (and / or / exclusions)
Text Search engines such as Lucene or Solr, long with their considerable functionality,
might also be used. The optional text search might also be code system specific, and servers
might have different implementations for different code systems
The date for which the expansion should be generated. if a date is provided, it means
that the server should use the value set / code system definitions as they were on the
given date, or return an error if this is not possible. Normally, the date is the current
conditions (which is the default value) but under some circumstances, systems need to
generate an expansion as it would have been in the past. A typical example of this would
be where code selection is constrained to the set of codes that were available when the
patient was treated, not when the record is being edited. Note that which date is appropriate
is a matter for implementation policy.
Paging support - where to start if a subset is desired (default = 0). Offset is number
of records (not number of pages)
Paging support - how many codes should be provided in a partial page view. Paging only
applies to flat expansions - servers ignore paging if the expansion is not flat. If count
= 0, the client is asking how large the expansion is. Servers SHOULD honor this request
for hierarchical expansions as well, and simply return the overall count
A [token](search.html#token) that specifies a system+code that is either a use or a language.
Designations that match by language or use are included in the expansion. If no designation
is specified, it is at the server discretion which designations to return
Controls whether inactive concepts are included or excluded in value set expansions. Note
that if the value set explicitly specifies that inactive codes are included, this parameter
can still remove them from a specific expansion, but this parameter cannot include them
if the value set excludes them
Controls whether or not the value set expansion nests codes or not (i.e. ValueSet.expansion.contains
.contains)
Controls whether or not the value set expansion is assembled for a user interface use
or not. Value sets intended for User Interface might include ['abstract' codes](codesystem.html#stat
us) or have nested contains with items with no code or abstract = true, with the sole purpose
of helping a user navigate through the list efficiently, where as a value set not generated
for UI use might be flat, and only contain the selectable codes in the value set. The
exact implications of 'for UI' depend on the code system, and what properties it exposes
for a terminology server to use. In the FHIR Specification itself, the value set expansions
are generated with excludeNotForUI = false, and the expansions used when generated schema
/ code etc, or performing validation, are all excludeNotForUI = true.
Specifies the language to be used for description in the expansions i.e. the language
to be used for ValueSet.expansion.contains.display
Code system, or a particular version of a code system to be excluded from the value set
expansion. The format is the same as a canonical URL: [system]|[version] - e.g. http://loinc.org|2.5
6
Specifies a version to use for a system, if the value set does not specify which one to
use. The format is the same as a canonical URL: [system]|[version] - e.g. http://loinc.org|2.56
Edge Case: Specifies a version to use for a system. If a value set specifies a different
version, an error is returned instead of the expansion. The format is the same as a canonical
URL: [system]|[version] - e.g. http://loinc.org|2.56
Edge Case: Specifies a version to use for a system. This parameter overrides any specified
version in the value set (and any it depends on). The format is the same as a canonical
URL: [system]|[version] - e.g. http://loinc.org|2.56. Note that this has obvious safety
issues, in that it may result in a value set expansion giving a different list of codes
that is both wrong and unsafe, and implementers should only use this capability reluctantly.
It primarily exists to deal with situations where specifications have fallen into decay
as time passes. If the value is override, the version used SHALL explicitly be represented
in the expansion parameters
The result of the expansion. Servers generating expansions SHOULD ensure that all the
parameters that affect the contents of the expansion are recorded in the ValueSet.expansion.paramete
r list
<?xml version="1.0" encoding="UTF-8"?>
<OperationDefinition xmlns="http://hl7.org/fhir"> <id value="ValueSet-expand"/> <text> <status value="extensions"/> <div xmlns="http://www.w3.org/1999/xhtml"> <p> URL: [base]/ValueSet/$expand</p> <p> URL: [base]/ValueSet/[id]/$expand</p> <p> Parameters</p> <table class="grid"> <tr> <td> <b> Use</b> </td> <td> <b> Name</b> </td> <td> <b> Scope</b> </td> <td> <b> Cardinality</b> </td> <td> <b> Type</b> </td> <td> <b> Binding</b> </td> <td> <b> Documentation</b> </td> </tr> <tr> <td> IN</td> <td> url</td> <td> type</td> <td> 0..1</td> <td> <a href="datatypes.html#uri">uri</a> </td> <td/> <td> <div> <p> A canonical reference to a value set. The server must know the value set (e.g.
it is defined explicitly in the server's value sets, or it is defined implicitly
by some code system known to the server</p>
</div> </td> </tr> <tr> <td> IN</td> <td> valueSet</td> <td> type</td> <td> 0..1</td> <td> <a href="valueset.html">ValueSet</a> </td> <td/> <td> <div> <p> The value set is provided directly as part of the request. Servers may choose not
to accept value sets in this fashion</p>
</div> </td> </tr> <tr> <td> IN</td> <td> valueSetVersion</td> <td> type</td> <td> 0..1</td> <td> <a href="datatypes.html#string">string</a> </td> <td/> <td> <div> <p> The identifier that is used to identify a specific version of the value set to
be used when generating the expansion. This is an arbitrary value managed by the
value set author and is not expected to be globally unique. For example, it might
be a timestamp (e.g. yyyymmdd) if a managed version is not available.</p>
</div> </td> </tr> <tr> <td> IN</td> <td> context</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#uri">uri</a> </td> <td/> <td> <div> <p> The context of the value set, so that the server can resolve this to a value set
to expand. The recommended format for this URI is [Structure Definition URL]#[name
or path into structure definition] e.g. http://hl7.org/fhir/StructureDefinition/observation-h
spc-height-hspcheight#Observation.interpretation. Other forms may be used but are
not defined. This form is only usable if the terminology server also has access
to the conformance registry that the server is using, but can be used to delegate
the mapping from an application context to a binding at run-time</p>
</div> </td> </tr> <tr> <td> IN</td> <td> contextDirection</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#code">code</a> </td> <td/> <td> <div> <p> If a context is provided, a context direction may also be provided. Valid values
are:</p>
<ul> <li> 'incoming': the codes a client can use for PUT/POST operations, and</li> <li> 'outgoing', the codes a client might receive from the server.</li> </ul> <p> The purpose is to inform the server whether to use the value set associated with
the context for reading or writing purposes (note: for most elements, this is the
same value set, but there are a few elements where the reading and writing value
sets are different)</p>
</div> </td> </tr> <tr> <td> IN</td> <td> filter</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#string">string</a> </td> <td/> <td> <div> <p> A text filter that is applied to restrict the codes that are returned (this is
useful in a UI context). The interpretation of this is delegated to the server
in order to allow to determine the most optimal search approach for the context.
The server can document the way this parameter works in
<a href="terminologycapabilities.html">TerminologyCapabilities</a> ..expansion.textFilter. Typical usage of this parameter includes functionality
like:
</p> <ul> <li> using left matching e.g. "acut ast"</li> <li> allowing for wild cards such as %, &, ?</li> <li> searching on definition as well as display(s)</li> <li> allowing for search conditions (and / or / exclusions)</li> </ul> <p> Text Search engines such as Lucene or Solr, long with their considerable functionality,
might also be used. The optional text search might also be code system specific,
and servers might have different implementations for different code systems</p>
</div> </td> </tr> <tr> <td> IN</td> <td> date</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#dateTime">dateTime</a> </td> <td/> <td> <div> <p> The date for which the expansion should be generated. if a date is provided, it
means that the server should use the value set / code system definitions as they
were on the given date, or return an error if this is not possible. Normally,
the date is the current conditions (which is the default value) but under some
circumstances, systems need to generate an expansion as it would have been in the
past. A typical example of this would be where code selection is constrained to
the set of codes that were available when the patient was treated, not when the
record is being edited. Note that which date is appropriate is a matter for implementation
policy.</p>
</div> </td> </tr> <tr> <td> IN</td> <td> offset</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#integer">integer</a> </td> <td/> <td> <div> <p> Paging support - where to start if a subset is desired (default = 0). Offset is
number of records (not number of pages)</p>
</div> </td> </tr> <tr> <td> IN</td> <td> count</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#integer">integer</a> </td> <td/> <td> <div> <p> Paging support - how many codes should be provided in a partial page view. Paging
only applies to flat expansions - servers ignore paging if the expansion is not
flat. If count = 0, the client is asking how large the expansion is. Servers SHOULD
honor this request for hierarchical expansions as well, and simply return the overall
count</p>
</div> </td> </tr> <tr> <td> IN</td> <td> includeDesignations</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#boolean">boolean</a> </td> <td/> <td> <div> <p> Controls whether concept designations are to be included or excluded in value set
expansions</p>
</div> </td> </tr> <tr> <td> IN</td> <td> designation</td> <td/> <td> 0..*</td> <td> <a href="datatypes.html#string">string</a> </td> <td/> <td> <div> <p> A <a href="search.html#token">token</a> that specifies a system+code that is either a use or a language. Designations
that match by language or use are included in the expansion. If no designation
is specified, it is at the server discretion which designations to return
</p> </div> </td> </tr> <tr> <td> IN</td> <td> includeDefinition</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#boolean">boolean</a> </td> <td/> <td> <div> <p> Controls whether the value set definition is included or excluded in value set
expansions</p>
</div> </td> </tr> <tr> <td> IN</td> <td> activeOnly</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#boolean">boolean</a> </td> <td/> <td> <div> <p> Controls whether inactive concepts are included or excluded in value set expansions.
Note that if the value set explicitly specifies that inactive codes are included,
this parameter can still remove them from a specific expansion, but this parameter
cannot include them if the value set excludes them</p>
</div> </td> </tr> <tr> <td> IN</td> <td> useSupplement</td> <td/> <td> 0..*</td> <td> <a href="datatypes.html#canonical">canonical</a> </td> <td/> <td> <div> <p> The supplement must be used when performing an expansion. Use of this parameter
should result in $expand behaving the same way as if the supplements were included
in the value set definition using the
<a href="http://hl7.org/fhir/extensions/StructureDefinition-valueset-supplement.html">http://hl7.org/fhir/StructureDefinition/valueset-supplement</a> </p> </div> </td> </tr> <tr> <td> IN</td> <td> excludeNested</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#boolean">boolean</a> </td> <td/> <td> <div> <p> Controls whether or not the value set expansion may nest codes or not (i.e. ValueSet.expansio
n.contains.contains). If excludeNested is set to true, the expansion MUST be flat
(no nesting). If excludeNested is set to false (default), however, nesting is
possible but not required</p>
</div> </td> </tr> <tr> <td> IN</td> <td> excludeNotForUI</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#boolean">boolean</a> </td> <td/> <td> <div> <p> Controls whether or not the value set expansion might include</p> <ul> <li> codes from the CodeSystem with a notSelectable property set to true as specified
in
<a href="codesystem.html#status">status</a> ] and in <a href="codesystem-concept-properties.html">Concept Properties</a> </li> <li> nested contains with no code (see <a href="valueset-definitions.html#ValueSet.expansion.contains.code">Contains</a> ) </li> <li> nested contains in the ValueSet with <a href="valueset-definitions.html#ValueSet.expansion.contains.abstract">abstract = true</a> </li> </ul> <p> One purpose of such concepts is helping a user navigate through the list efficiently.
If excludeNotForUI is set to true, the concepts as described above will be excluded
from the expansion. If excludeNotForUI is set to false (default), all concepts
as described above may be part of the expansion. In the FHIR Specification itself,
the value set expansions are generated with excludeNotForUI = false, and the expansions
used when generating schema / code etc., or performing validation, are all excludeNotForUI
= true.</p>
</div> </td> </tr> <tr> <td> IN</td> <td> excludePostCoordinated</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#boolean">boolean</a> </td> <td/> <td> <div> <p> Controls whether or not the value set expansion includes post coordinated codes</p> </div> </td> </tr> <tr> <td> IN</td> <td> displayLanguage</td> <td/> <td> 0..1</td> <td> <a href="datatypes.html#code">code</a> </td> <td/> <td> <div> <p> Specifies the language to be used for description in the expansions i.e. the language
to be used for ValueSet.expansion.contains.display</p>
</div> </td> </tr> <tr> <td> IN</td> <td> property</td> <td/> <td> 0..*</td> <td> <a href="datatypes.html#string">string</a> </td> <td/> <td> <div> <p> A request to return a particular property in the expansion. The returned property
may include subproperties. May be either a code from the code system definition
(convenient) or a the formal URI that refers to the property. Note that property
names can clash, so using a URI is recommended. The special value '*' means all
properties and their sub-properties known to the server</p>
</div> </td> </tr> <tr> <td> IN</td> <td> exclude-system</td> <td/> <td> 0..*</td> <td> <a href="datatypes.html#canonical">canonical</a> </td> <td/> <td> <div> <p> Code system, or a particular version of a code system to be excluded from the value
set expansion. The format is the same as a canonical URL: [system]|[version] -
e.g. http://loinc.org|2.56</p>
</div> </td> </tr> <tr> <td> IN</td> <td> system-version</td> <td/> <td> 0..*</td> <td> <a href="datatypes.html#canonical">canonical</a> </td> <td/> <td> <div> <p> Specifies a version to use for a system, if the value set does not specify which
one to use. The format is the same as a canonical URL: [system]|[version] - e.g.
http://loinc.org|2.56</p>
</div> </td> </tr> <tr> <td> IN</td> <td> check-system-version</td> <td/> <td> 0..*</td> <td> <a href="datatypes.html#canonical">canonical</a> </td> <td/> <td> <div> <p> Edge Case: Specifies a version to use for a system. If a value set specifies a
different version, an error is returned instead of the expansion. The format is
the same as a canonical URL: [system]|[version] - e.g. http://loinc.org|2.56</p>
</div> </td> </tr> <tr> <td> IN</td> <td> force-system-version</td> <td/> <td> 0..*</td> <td> <a href="datatypes.html#canonical">canonical</a> </td> <td/> <td> <div> <p> Edge Case: Specifies a version to use for a system. This parameter overrides any
specified version in the value set (and any it depends on). The format is the same
as a canonical URL: [system]|[version] - e.g. http://loinc.org|2.56. Note that
this has obvious safety issues, in that it may result in a value set expansion
giving a different list of codes that is both wrong and unsafe, and implementers
should only use this capability reluctantly. It primarily exists to deal with situations
where specifications have fallen into decay as time passes. If the value is override,
the version used SHALL explicitly be represented in the expansion parameters</p>
</div> </td> </tr> <tr> <td> OUT</td> <td> return</td> <td/> <td> 1..1</td> <td> <a href="valueset.html">ValueSet</a> </td> <td/> <td> <div> <p> The result of the expansion. Servers generating expansions SHOULD ensure that all
the parameters that affect the contents of the expansion are recorded in the ValueSet.expansi
on.parameter list</p>
</div> </td> </tr> </table> <div> <p> The value set expansion returned by this query should be treated as a transient
result that will change over time (whether it does or not depends on how the value
set is specified), so applications should repeat the operation each time the value
set is used.</p>
<p> When available, ValueSet.status and ValueSet.version from the ValueSet resource
instance which contains the definition SHALL be persisted to the ValueSet resource
instance which contains the expansion.</p>
<p> If the expansion is too large (at the discretion of the server), the server MAY
return an error (OperationOutcome with code too-costly). Clients can work through
large flat expansions in a set of pages (partial views of the full expansion) instead
of just getting the full expansion in a single exchange by using offset and count
parameters, or use the count parameter to request a subset of the expansion for
limited purposes. Servers are not obliged to support paging, but if they do, SHALL
support both the offset and count parameters. Hierarchical expansions are not subject
to paging and servers simply return the entire expansion.</p>
<p> Different servers may return different results from expanding a value set for the
following reasons:</p>
<ul> <li> The underlying code systems are different (e.g. different versions, possibly with
different defined behavior)</li>
<li> The server optimizes filter includes differently, such as sorting by code frequency</li> <li> Servers introduce arbitrary groups to assist a user to navigate the lists based
either on extensions in the definition, or additional knowledge available to the
server</li>
</ul> <p> When a server cannot correctly expand a value set because it does not fully understand
the code systems (e.g. it has the wrong version, or incomplete definitions) then
it SHALL return an error. If the value set itself is unbounded due to the inclusion
of post-coordinated value sets (e.g. SNOMED CT, UCUM), then the extension
<a href="http://hl7.org/fhir/extensions/StructureDefinition-valueset-unclosed.html">http://hl7.org/fhir/StructureDefinition/valueset-unclosed</a> can be used to indicate that the expansion is incomplete </p> </div> </div> </text> <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm"> <valueInteger value="5"/> </extension> <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status"> <valueCode value="normative"/> </extension> <url value="http://hl7.org/fhir/OperationDefinition/ValueSet-expand"/> <version value="5.0.0-draft-final"/> <name value="Expand"/> <title value="Value Set Expansion"/> <status value="active"/> <kind value="operation"/> <experimental value="false"/> <date value="2023-03-01T23:03:57+11:00"/> <publisher value="HL7 (FHIR Project)"/> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> <telecom> <system value="email"/> <value value="fhir@lists.hl7.org"/> </telecom> </contact> <description value="The definition of a value set is used to create a simple collection of codes suitable
for use for data entry or validation.
If the operation is not called at the instance level, one of the in parameters
url, context or valueSet must be provided. An expanded value set will be returned,
or an OperationOutcome with an error message."/>
<jurisdiction> <coding> <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/> <code value="001"/> <display value="World"/> </coding> </jurisdiction> <affectsState value="false"/> <code value="expand"/> <comment value="The value set expansion returned by this query should be treated as a transient
result that will change over time (whether it does or not depends on how the value
set is specified), so applications should repeat the operation each time the value
set is used.
When available, ValueSet.status and ValueSet.version from the ValueSet resource
instance which contains the definition SHALL be persisted to the ValueSet resource
instance which contains the expansion.
If the expansion is too large (at the discretion of the server), the server MAY
return an error (OperationOutcome with code too-costly). Clients can work through
large flat expansions in a set of pages (partial views of the full expansion) instead
of just getting the full expansion in a single exchange by using offset and count
parameters, or use the count parameter to request a subset of the expansion for
limited purposes. Servers are not obliged to support paging, but if they do, SHALL
support both the offset and count parameters. Hierarchical expansions are not subject
to paging and servers simply return the entire expansion.
Different servers may return different results from expanding a value set for the
following reasons:
* The underlying code systems are different (e.g. different versions, possibly
with different defined behavior)
* The server optimizes filter includes differently, such as sorting by code frequency
* Servers introduce arbitrary groups to assist a user to navigate the lists based
either on extensions in the definition, or additional knowledge available to the
server
When a server cannot correctly expand a value set because it does not fully understand
the code systems (e.g. it has the wrong version, or incomplete definitions) then
it SHALL return an error. If the value set itself is unbounded due to the inclusion
of post-coordinated value sets (e.g. SNOMED CT, UCUM), then the extension [http://hl7.org/fhi
r/StructureDefinition/valueset-unclosed](http://hl7.org/fhir/extensions/StructureDefinition-va
lueset-unclosed.html) can be used to indicate that the expansion is incomplete"/>
<resource value="ValueSet"/> <system value="false"/> <type value="true"/> <instance value="true"/> <parameter> <name value="url"/> <use value="in"/> <scope value="type"/> <min value="0"/> <max value="1"/> <documentation value="A canonical reference to a value set. The server must know the value set (e.g.
it is defined explicitly in the server's value sets, or it is defined implicitly
by some code system known to the server"/>
<type value="uri"/> </parameter> <parameter> <name value="valueSet"/> <use value="in"/> <scope value="type"/> <min value="0"/> <max value="1"/> <documentation value="The value set is provided directly as part of the request. Servers may choose not
to accept value sets in this fashion"/>
<type value="ValueSet"/> </parameter> <parameter> <name value="valueSetVersion"/> <use value="in"/> <scope value="type"/> <min value="0"/> <max value="1"/> <documentation value="The identifier that is used to identify a specific version of the value set to
be used when generating the expansion. This is an arbitrary value managed by the
value set author and is not expected to be globally unique. For example, it might
be a timestamp (e.g. yyyymmdd) if a managed version is not available."/>
<type value="string"/> </parameter> <parameter> <name value="context"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="The context of the value set, so that the server can resolve this to a value set
to expand. The recommended format for this URI is [Structure Definition URL]#[name
or path into structure definition] e.g. http://hl7.org/fhir/StructureDefinition/observation-h
spc-height-hspcheight#Observation.interpretation. Other forms may be used but are
not defined. This form is only usable if the terminology server also has access
to the conformance registry that the server is using, but can be used to delegate
the mapping from an application context to a binding at run-time"/>
<type value="uri"/> </parameter> <parameter> <name value="contextDirection"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="If a context is provided, a context direction may also be provided. Valid values
are:
* 'incoming': the codes a client can use for PUT/POST operations, and
* 'outgoing', the codes a client might receive from the server.
The purpose is to inform the server whether to use the value set associated with
the context for reading or writing purposes (note: for most elements, this is the
same value set, but there are a few elements where the reading and writing value
sets are different)"/>
<type value="code"/> </parameter> <parameter> <name value="filter"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="A text filter that is applied to restrict the codes that are returned (this is
useful in a UI context). The interpretation of this is delegated to the server
in order to allow to determine the most optimal search approach for the context.
The server can document the way this parameter works in [TerminologyCapabilities](terminology
capabilities.html)..expansion.textFilter. Typical usage of this parameter includes
functionality like:
* using left matching e.g. "acut ast"
* allowing for wild cards such as %, &, ?
* searching on definition as well as display(s)
* allowing for search conditions (and / or / exclusions)
Text Search engines such as Lucene or Solr, long with their considerable functionality,
might also be used. The optional text search might also be code system specific,
and servers might have different implementations for different code systems"/>
<type value="string"/> </parameter> <parameter> <name value="date"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="The date for which the expansion should be generated. if a date is provided, it
means that the server should use the value set / code system definitions as they
were on the given date, or return an error if this is not possible. Normally,
the date is the current conditions (which is the default value) but under some
circumstances, systems need to generate an expansion as it would have been in the
past. A typical example of this would be where code selection is constrained to
the set of codes that were available when the patient was treated, not when the
record is being edited. Note that which date is appropriate is a matter for implementation
policy."/>
<type value="dateTime"/> </parameter> <parameter> <name value="offset"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="Paging support - where to start if a subset is desired (default = 0). Offset is
number of records (not number of pages)"/>
<type value="integer"/> </parameter> <parameter> <name value="count"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="Paging support - how many codes should be provided in a partial page view. Paging
only applies to flat expansions - servers ignore paging if the expansion is not
flat. If count = 0, the client is asking how large the expansion is. Servers SHOULD
honor this request for hierarchical expansions as well, and simply return the overall
count"/>
<type value="integer"/> </parameter> <parameter> <name value="includeDesignations"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="Controls whether concept designations are to be included or excluded in value set
expansions"/>
<type value="boolean"/> </parameter> <parameter> <name value="designation"/> <use value="in"/> <min value="0"/> <max value="*"/> <documentation value="A [token](search.html#token) that specifies a system+code that is either a use
or a language. Designations that match by language or use are included in the expansion.
If no designation is specified, it is at the server discretion which designations
to return"/>
<type value="string"/> </parameter> <parameter> <name value="includeDefinition"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="Controls whether the value set definition is included or excluded in value set
expansions"/>
<type value="boolean"/> </parameter> <parameter> <name value="activeOnly"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="Controls whether inactive concepts are included or excluded in value set expansions.
Note that if the value set explicitly specifies that inactive codes are included,
this parameter can still remove them from a specific expansion, but this parameter
cannot include them if the value set excludes them"/>
<type value="boolean"/> </parameter> <parameter> <name value="useSupplement"/> <use value="in"/> <min value="0"/> <max value="*"/> <documentation value="The supplement must be used when performing an expansion. Use of this parameter
should result in $expand behaving the same way as if the supplements were included
in the value set definition using the [http://hl7.org/fhir/StructureDefinition/valueset-suppl
ement](http://hl7.org/fhir/extensions/StructureDefinition-valueset-supplement.html)"/>
<type value="canonical"/> </parameter> <parameter> <name value="excludeNested"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="Controls whether or not the value set expansion may nest codes or not (i.e. ValueSet.expansio
n.contains.contains). If excludeNested is set to true, the expansion MUST be flat
(no nesting). If excludeNested is set to false (default), however, nesting is
possible but not required"/>
<type value="boolean"/> </parameter> <parameter> <name value="excludeNotForUI"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="Controls whether or not the value set expansion might include
* codes from the CodeSystem with a notSelectable property set to true as specified
in [status](codesystem.html#status)] and in [Concept Properties](codesystem-concept-propertie
s.html)
* nested contains with no code (see [Contains](valueset-definitions.html#ValueSet.expansion.c
ontains.code))
* nested contains in the ValueSet with [abstract = true](valueset-definitions.html#ValueSet.e
xpansion.contains.abstract)
One purpose of such concepts is helping a user navigate through the list efficiently.
If excludeNotForUI is set to true, the concepts as described above will be excluded
from the expansion. If excludeNotForUI is set to false (default), all concepts
as described above may be part of the expansion. In the FHIR Specification itself,
the value set expansions are generated with excludeNotForUI = false, and the expansions
used when generating schema / code etc., or performing validation, are all excludeNotForUI
= true."/>
<type value="boolean"/> </parameter> <parameter> <name value="excludePostCoordinated"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="Controls whether or not the value set expansion includes post coordinated codes"/> <type value="boolean"/> </parameter> <parameter> <name value="displayLanguage"/> <use value="in"/> <min value="0"/> <max value="1"/> <documentation value="Specifies the language to be used for description in the expansions i.e. the language
to be used for ValueSet.expansion.contains.display"/>
<type value="code"/> </parameter> <parameter> <name value="property"/> <use value="in"/> <min value="0"/> <max value="*"/> <documentation value="A request to return a particular property in the expansion. The returned property
may include subproperties. May be either a code from the code system definition
(convenient) or a the formal URI that refers to the property. Note that property
names can clash, so using a URI is recommended. The special value '*' means all
properties and their sub-properties known to the server"/>
<type value="string"/> </parameter> <parameter> <name value="exclude-system"/> <use value="in"/> <min value="0"/> <max value="*"/> <documentation value="Code system, or a particular version of a code system to be excluded from the value
set expansion. The format is the same as a canonical URL: [system]|[version] -
e.g. http://loinc.org|2.56"/>
<type value="canonical"/> </parameter> <parameter> <name value="system-version"/> <use value="in"/> <min value="0"/> <max value="*"/> <documentation value="Specifies a version to use for a system, if the value set does not specify which
one to use. The format is the same as a canonical URL: [system]|[version] - e.g.
http://loinc.org|2.56"/>
<type value="canonical"/> </parameter> <parameter> <name value="check-system-version"/> <use value="in"/> <min value="0"/> <max value="*"/> <documentation value="Edge Case: Specifies a version to use for a system. If a value set specifies a
different version, an error is returned instead of the expansion. The format is
the same as a canonical URL: [system]|[version] - e.g. http://loinc.org|2.56"/>
<type value="canonical"/> </parameter> <parameter> <name value="force-system-version"/> <use value="in"/> <min value="0"/> <max value="*"/> <documentation value="Edge Case: Specifies a version to use for a system. This parameter overrides any
specified version in the value set (and any it depends on). The format is the same
as a canonical URL: [system]|[version] - e.g. http://loinc.org|2.56. Note that
this has obvious safety issues, in that it may result in a value set expansion
giving a different list of codes that is both wrong and unsafe, and implementers
should only use this capability reluctantly. It primarily exists to deal with situations
where specifications have fallen into decay as time passes. If the value is override,
the version used SHALL explicitly be represented in the expansion parameters"/>
<type value="canonical"/> </parameter> <parameter> <name value="return"/> <use value="out"/> <min value="1"/> <max value="1"/> <documentation value="The result of the expansion. Servers generating expansions SHOULD ensure that all
the parameters that affect the contents of the expansion are recorded in the ValueSet.expansi
on.parameter list"/>
<type value="ValueSet"/> </parameter>
</
OperationDefinition
>
Usage
note:
every
effort
has
been
made
to
ensure
that
the
examples
are
correct
and
useful,
but
they
are
not
a
normative
part
of
the
specification.