Canonical Resource Management Infrastructure Implementation Guide
1.0.0-ballot2 - Ballot
Canonical Resource Management Infrastructure Implementation Guide
1.0.0-ballot2 - Ballot
This page is part of the Canonical Resource Management Infrastructure Implementation Guide (v1.0.0-ballot2: STU1 Ballot 2) based on FHIR (HL7® FHIR® Standard) R4. . For a full list of available versions, see the Directory of published versions
This page describes and documents the use cases and conformance expectations of a terminology service to support authoring, distribution, and evaluation of FHIR-based knowledge artifact specifications as described in this implementation guide.
This implementation guide is not advocating for any particular central authority for terminology content, rather the intent is to propose a capability statement that enables publishers to build consistent and interoperable terminology services that support authoring, distribution, and implementation of FHIR-based knowledge artifacts.
This implementation guide is not prescriptive about authentication or authorization, but strongly recommends that these capabilities be addressed through standard mechanisms, as described in FHIR standard security mechanisms.
Beyond the basic required use cases of searching, retrieving, and expanding value sets, applications that reference value sets that are defined in terms of code systems from different authorities and with different publishing timelines face common challenges related to stable expansion of those value sets. To address that general problem, this implementation guide proposes to use the Library resource as an artifact collection. Artifact collections are libraries of knowledge artifacts used to package sets of artifacts for development and release. From the perspective of a terminology service, artifact collections provide two main capabilities:
Note that during the authoring phase, the value sets referenced by artifacts will change, but once released, the set is stable. Throughout this process, the focus of the capabilities supported by this service description are intended to ensure stable expansion of the value sets referenced by the artifacts.
As a version manifest, an artifact collection specifies versioned canonical references for dependencies using relatedArtifact elements with a type of depends-on.
NOTE: If the version of an artifact is specified explicitly as part of the declaration in the artifact, the manifest approach cannot be used to override that version. For example, if an artifact explicitly references the version of a value set, the manifest cannot override that version.
Artifact collections can specify expansion rules for value sets referenced by artifacts in the collection. This is done using the cqf-expansionParameters extension to reference a contained Parameters resource, where the parameter elements provide a default value for parameters to the $expand operation, consistent with the conformance requirements for the $expand operation supported by an artifact terminology service, including support for the following parameters:
activeOnlysystem-version (or canonical-version)check-system-version (or check-canonical-version)force-system-version (or force-canonical-version)expansion parameter (defined in the crmi-valueset-expand)includeDraft parameter (defined in the crmi-valueset-expand)Because this capability results in the potential for parameter values to be supplied in multiple places, the following rules apply:
valueSetVersion parameter to the $expandsystem-version parameter to the $expandTerminology services MAY act as a repository for content that is managed and created elsewhere (i.e. hosted content AKA a convenience copy), or they MAY provide features to author and manage content directly, or any combination. When hosting content that is managed elsewhere, the service must ensure that the content of the resource is materially the same (i.e. the values for all elements are the same where those elements are specified in the Shareable and Publishable profiles) as the source of truth. In particular, for systems that provide both management and hosting of externally managed content, the status element for hosted content SHALL be the same as the status of the content in the source of truth.
SHALL Represent basic CodeSystem information, as specified by the ShareableCodeSystem profile, which includes url, version, name, status, experimental, publisher, description, caseSensitive, content, and concept.
For published CodeSystems, SHALL represent publishable CodeSystem information, as specified by the CRMIPublishableCodeSystem profile.
For hosted content, the data-absent-reason extension with a value of unknown MAY be used to satisfy required cardinality constraints of the Shareable and Publishable code system profiles when an element is not present in the source of truth for the content.
CodeSystem resources returned by the repository SHALL use the meta.profile element to indicate which profiles the CodeSystem resource conforms to.
SHALL support CodeSystem read by the server-defined id for the CodeSystem
SHALL support CodeSystem/$lookup
When determining the URI for a code system, the HL7 Universal Terminology Governance (UTG) site is the source of truth. If a code system is not identified there, submit a request with the HL7 Terminology Authority to identify an appropriate URL. For example, HCPCS Level II codes are not specified yet, discussion can be found here.
In accordance with the FHIR specification, CodeSystem resources, and references to code systems SHALL use the URI as specified by the HL7 terminology authority. In addition, version identifiers for code systems are specified according to the rules identified by the code system authority. For example, for SNOMED-CT, this means the version string is required to specify the edition and the version:
http://snomed.info/sct/731000124108/version/20150301
The edition identifier for the US Edition is 731000124108, and the version in the
above example is the March 2015 release, specified as YYYYMMDD, 20150301.
Note that when a code system authority has not established a versioning system, terminology servers may, as a practical matter, determine an appropriate versioning system to enable consistent use of content from that code system. However, in this case, the selected versioning scheme SHALL be brought to the HL7 Terminology Authority for consideration as the standard versioning scheme for that code system.
SHALL Represent computable ValueSet information, as specified by the CRMIComputableValueSet profile, which specifies the definition of a value set using established extensions, or with the compose element, including in particular the ability to use the inactive element of the include to indicate that a specific code is inactive in the code system but should still be included in the expansion.
For hosted content, the data-absent-reason extension with a value of unknown MAY be used to satisfy required cardinality constraints of the Shareable and Publishable value set profiles when an element is not present in the source of truth for the content.
ValueSet resources returned by the repository SHALL use the meta.profile element to indicate which profiles the ValueSet conforms to, Shareable, Publishable, Computable, or Expanded.
SHALL Represent expanded ValueSet information, as specified by the CRMIExpandedValueSet profile, which specifies the complete content of a value set using the expansion element, including inactive codes specified in the compose.
For published ValueSets, SHALL represent publishable ValueSet information, as specified by the CRMIPublishableValueSet profile.
SHALL support ValueSet read, by the server-defined id for the ValueSet
manifest parameter (defined in the crmi-valueset-expand)expansion parameter (defined in the crmi-valueset-expand)includeDraft parameter (defined in the crmi-valueset-expand)SHALL Represent basic artifact collection information, as specified by the CRMIManifestLibrary profile, which includes identifier, title, type, date, useContext, effectivePeriod, and terminology references
For published artifact collections, SHALL represent publishable artifact collection information as specified by the CRMIPublishableLibrary profile.
SHALL support Library read, by the server-defined id for the library
includeDraft parameter (defined in the crmi-valueset-expand)expansion parameter (defined in the crmi-valueset-expand)valueSetVersion parameter to the $expandsystem-version parameter to the $expanddraft status (using POST)draft status (using PUT)draft to active (using PUT)active status to retired (using PUT)draft statusurl and version as another librarySHALL support the metadata?mode=terminology, returning a list of all supported code systems, whether they are explicitly made available as CodeSystem resources or not
Services MAY require authentication. If authentication is required, it SHALL be in the form of an authentication header (usually a bearer token) that the user can determine in advance and provide to their FHIR tooling in some configuration.
contains and exact modifierstextThe above capabilities are formally captured in the following capability statement:
CRMIArtifactTerminologyService
This is the computable representation of an example Chronic Liver Disease value set. It contains two concepts that are active (as of the 2019-09 release of the US Edition of SNOMED-CT) and one concept that was last active in the 2015-03 release).
The compose element of this value set is:
"compose": {
"include": [
{
"system": "http://snomed.info/sct",
"concept": [
{
"code": "1116000",
"display": "Chronic aggressive type B viral hepatitis (disorder)"
},
{
"code": "10295004",
"display": "Chronic viral hepatitis (disorder)"
}
]
},
{
"system": "http://snomed.info/sct",
"version": "http://snomed.info/sct/731000124108/version/20150301",
"concept": [
{
"code": "111370006",
"display": "Cirrhosis of liver not due to alcohol (disorder)"
}
]
}
]
}
Note specifically the use of the inactive element to indicate that the
value set definition contains inactive codes, and the use of separate
include elements, one for the codes that do not specify a code system version,
and one for the legacy code from version http://snomed.info/sct/731000124108/version/20150301.
Given the following $expand:
[base]/ValueSet/chronic-liver-disease-legacy-example/$expand
The expected result expansion is:
"expansion": {
"timestamp": "2021-02-05T08:57:00-06:00",
"contains": [
{
"system": "http://snomed.info/sct",
"code": "1116000",
"display": "Chronic aggressive type B viral hepatitis (disorder)"
},
{
"system": "http://snomed.info/sct",
"code": "10295004",
"display": "Chronic viral hepatitis (disorder)"
},
{
"system": "http://snomed.info/sct",
"inactive": true,
"code": "111370006",
"display": "Cirrhosis of liver not due to alcohol (disorder)"
}
]
}
Note the use of the inactive element to indicate the code 111370006 is inactive in the
current version of SNOMED (i.e. the version of SNOMED that was active when this
expansion was produced, and the use of the timestamp to ensure that date is known).
Given the following $expand:
[base]/ValueSet/chronic-liver-disease-legacy-example/$expand?activeOnly=true
The expected result expansion is:
"expansion": {
"timestamp": "2021-02-05T08:57:00-06:00",
"parameter": [
{
"name": "activeOnly",
"valueBoolean": true
}
],
"contains": [
{
"system": "http://snomed.info/sct",
"code": "1116000",
"display": "Chronic aggressive type B viral hepatitis (disorder)"
},
{
"system": "http://snomed.info/sct",
"code": "10295004",
"display": "Chronic viral hepatitis (disorder)"
}
]
}
The result of the activeOnly parameter is to exclude the inactive code, even
though it was explicitly included in the value set definition.
Given the following $expand:
[base]/ValueSet/chronic-liver-disease-legacy-example/$expand?valueSetVersion=2020-05&system-version=http://snomed.info/sct|http://snomed.info/sct/731000124108/version/20150301
The expected result expansion is:
"expansion": {
"timestamp": "2021-02-05T08:57:00-06:00",
"parameter": [
{
"name": "valueSetVersion",
"valueString": "2020-05"
},
{
"name": "system-version",
"valueUri": "http://snomed.info/sct|http://snomed.info/sct/731000124108/version/20190901"
}
],
"contains": [
{
"system": "http://snomed.info/sct",
"code": "1116000",
"display": "Chronic aggressive type B viral hepatitis (disorder)"
},
{
"system": "http://snomed.info/sct",
"code": "10295004",
"display": "Chronic viral hepatitis (disorder)"
},
{
"system": "http://snomed.info/sct",
"inactive": true,
"code": "111370006",
"display": "Cirrhosis of liver not due to alcohol (disorder)"
}
]
}
Note this expansion contains the same codes as the current example, but is explicitly
bound to the 2019-09 version of the US Edition of the SNOMED code system (http://snomed.info/sct/731000124108/version/20190901).
From the perspective of artifact development, artifact collections are used to represent collections of artifacts in 2 different ways:
Note that as the artifacts in the collection are developed, different aspects of the definition will be specified at different points of the process. For example, the initial definition will typically include a set of artifacts, as well as an initial set of proposed code system versions to be used. This provides for stable expansion of value sets while the artifacts are being developed. As development progresses, more and more aspects of the collection definition are finalized, resulting in more versions being pinned down. To illustrate these usages, we provide three artifact collection examples, one to illustrate the overall definition of a collection, one to illustrate the selection of code systems at the beginning of a development cycle, and one to illustrate a final release of a collection definition with artifact versions, value set versions, and code system versions completely specified.
The following example illustrates an overall collection that contains multiple version manifests and releases over time:
Note that as an organizer, this library just contains the collection-level information.
This example illustrates the use of a draft quality program description to specify the version of SNOMED to be used for valuesets used by artifacts in the quality program.
"contained": [
{
"resourceType": "Parameters",
"id": "exp-params",
"parameter": [
{
"name" : "system-version",
"valueUri" : "http://snomed.info/sct|http://snomed.info/sct/731000124108/version/20190901"
},
{
"name": "activeOnly",
"valueBoolean": true
},
{
"name": "includeDraft",
"valueBoolean": true
}
]
}
],
"extension": [
{
"url": "http://hl7.org/fhir/uv/crmi/StructureDefinition/crmi-expansionParameters",
"valueReference": {
"reference": "#exp-params"
}
}
],
This example indicates that unless specified explicitly by artifacts in the collection, the 2019-09-01 version of SNOMED SHALL be used when expanding value sets that reference SNOMED.
Note that the version of SNOMED in use is still listed as a dependency in the artifact collection to support providing a complete listing of dependencies in the version manifest. When this is done, the version provided in the expansion parameters SHALL take precedence (though the version manifest SHOULD be consistent with the expansion parameters).
"relatedArtifact": [
{
"type": "depends-on",
"resource": "http://snomed.info/sct|http://snomed.info/sct/731000124108/version/20190901",
"display": "SNOMED-CT US Edition, 2019-09-01"
}
]
The following example illustrates a collection that is an active instance of an artifact collection release used to provide stable extensions for the released artifacts in the collection.
Specifically, the collection release uses the expansion parameter in the contained expansion parameters at the artifact collection level to indicate that all value sets used with artifacts in the program should expand using this expansion identifier:
{
"name": "expansion",
"valueUri": "eCQM%20Update%202020-05-07"
}
In addition, the collection release specifies versions of code systems, value sets, and artifacts included in the release:
{
"type": "depends-on",
"resource": "http://snomed.info/sct|http://snomed.info/sct/731000124108/version/20190901",
"display": "SNOMED-CT US Edition, 2019-09-01"
},
{
"type": "depends-on",
"resource": "http://hl7.org/fhir/uv/crmi/ValueSet/chronic-liver-disease-legacy-example|2020-05",
"display": "Chronic Liver Disease, Legacy Example (2020-05)"
},
{
"type": "composed-of",
"resource": "http://hl7.org/fhir/uv/crmi/Measure/measure-exm124-FHIR|9.0.0",
"display": "Cervical Cancer Screening"
},
{
"type": "composed-of",
"resource": "http://hl7.org/fhir/uv/crmi/Measure/measure-exm125-FHIR",
"display": "Breast Cancer Screening"
},
{
"type": "composed-of",
"resource": "http://hl7.org/fhir/uv/crmi/Measure/measure-exm130-FHIR",
"display": "Colorectal Cancer Screening"
},
{
"type": "composed-of",
"resource": "http://hl7.org/fhir/uv/crmi/Measure/measure-exm146-FHIR",
"display": "Appropriate Testing for Children with Pharyngitis"
}
Given this use of an artifact collection, the manifest parameter can be used in the $expand operation to provide values for the relevant parameters:
[base]/ValueSet/chronic-liver-disease-legacy-example/$expand?manifest=http://hl7.org/fhir/uv/crmi/Library/ecqm-update-2020
This is effectively an alternative mechanism for expressing the same value set and code system version specific expansion above, and results in the same expansion, with the additional manifest parameter:
"expansion": {
"timestamp": "2021-02-05T08:57:00-06:00",
"parameter": [
{
"name": "valueSetVersion",
"valueString": "2020-05"
},
{
"name": "system-version",
"valueUri": "http://snomed.info/sct|http://snomed.info/sct/731000124108/version/20190901"
},
{
"name": "manifest",
"valueUri": "http://hl7.org/fhir/uv/crmi/Library/ecqm-update-2020"
}
],
"contains": [
{
"system": "http://snomed.info/sct",
"code": "1116000",
"display": "Chronic aggressive type B viral hepatitis (disorder)"
},
{
"system": "http://snomed.info/sct",
"code": "10295004",
"display": "Chronic viral hepatitis (disorder)"
},
{
"system": "http://snomed.info/sct",
"inactive": true,
"code": "111370006",
"display": "Cirrhosis of liver not due to alcohol (disorder)"
}
]
}
Similarly, when using a release for the manifest parameter:
[base]/ValueSet/chronic-liver-disease-legacy-example/$expand?manifest=http://hl7.org/fhir/uv/crmi/Library/ecqm-update-2020-05-07
This is effectively the same as providing the expansion parameter to the value set expand, and results in the expansion with the specified expansion identifier:
"expansion": {
"identifier": "eCQM%20Update%202020-05-07",
"timestamp": "2021-02-05T08:57:00-06:00",
"parameter": [
{
"name": "valueSetVersion",
"valueString": "2020-05"
},
{
"name": "system-version",
"valueUri": "http://snomed.info/sct|http://snomed.info/sct/731000124108/version/20190901"
},
{
"name": "manifest",
"valueUri": "http://hl7.org/fhir/uv/crmi/Library/ecqm-update-2020-05-07"
}
],
"contains": [
{
"system": "http://snomed.info/sct",
"code": "1116000",
"display": "Chronic aggressive type B viral hepatitis (disorder)"
},
{
"system": "http://snomed.info/sct",
"code": "10295004",
"display": "Chronic viral hepatitis (disorder)"
},
{
"system": "http://snomed.info/sct",
"inactive": true,
"code": "111370006",
"display": "Cirrhosis of liver not due to alcohol (disorder)"
}
]
}
In addition to the use of the expansion parameter of the $expand operation, terminology services SHOULD support searching for a particular ValueSet expansion using the expansion search parameter:
[base]/ValueSet?url=http://hl7.org/fhir/uv/crmi/ValueSet/chronic-liver-disease-legacy-example&expansion=eCQM%20Update%202020-05-07
The result of this search is the same as requesting an $expand with the expansion parameter.
IG © 2022+ HL7 International / Clinical Decision Support. Package hl7.fhir.uv.crmi#1.0.0-ballot2 based on FHIR 4.0.1. Generated 2023-12-20
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