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This page documents requirements common to all IE Core actors in this guide. The conformance verbs - SHALL, SHOULD, MAY - used in this guide are defined in FHIR Conformance Rules.
The Profiles and Extensions page lists the IE Core Profiles defined for this implementation guide. IE Core Profile StructureDefinitions define the minimum elements, extensions, vocabularies, and ValueSets that SHALL be present and constrains how the elements are used when using the profile. Each IE Core Profile page has a "Quick Start" guide to the supported FHIR RESTfUL transactions for each profile.
The IE Core Profile elements include Mandatory, Must Support, and Additional IECDI Requirements. Mandatory elements are required and have a minimum cardinality of 1 (min=1). Must Support element server and client expectations are defined by IE Core. Additional IECDI Requirements elements are neither Mandatory nor Must Support but designated IECDI Requirements for certification and, for certified systems, are equivalent to Must Support elements. All Mandatory, Must Support, or Additional IECDI Requirements are in scope for certification testing. The Must Support page defines the server and client expectations for processing these different element requirements and illustrates how they are displayed and documented.
The Capability Statements page outlines conformance requirements and expectations for the IE Core Servers and Client applications. In addition, the IE Core Server CapabilityStatement and IE Core Client CapabilityStatement identify the specific profiles and RESTful transactions that need support. The IE Core Profiles identify the structural constraints, terminology bindings, and invariants. Similarly, each IE Core SearchParameter and Operation resource specify how the server understands them. However, implementers must refer to the CapabilityStatement for details on the RESTful transactions, specific profiles, and the search parameters applicable to each IE Core actor.
There are two different ways to implement IE Core:
Systems may deploy and support one or more IE Core Profiles to represent clinical information. They use the profile's content model without any expectations to implement the IE Core interactions.
An example scenario would be a server using only the FHIR Bulk Data Access (Flat FHIR) approach to export the IE Core Data for Interoperability resources. For this server, the IE Core interactions are unnecessary.
To support a IE Core Profile, a server:
iEHR
CapabilityStatement.rest.resource.supportedProfile element.
The IE Core Profile's official or "canonical" URL is located on each IE Core Profile page
example CapabilityStatement snippet for a server supporting the IE Core Patient Profile:
{
"resourceType": "CapabilityStatement",
...
"rest": [
{
"mode": "server",
...
"resource": [
...
{
"type": "Patient",
"supportedProfile": [
"http://iehr.ai/fhir/ie/core/StructureDefinition/ie-core-patient"
],
...
}
]
}
]
}
Servers may deploy and support one or more IE Core Profiles to represent clinical information and one or more of the following IE Core interactions:
Servers implementing both can claim conformance to the IE Core Profile content structure and the RESTful interactions defined by implementing all or parts of the IE Core CapabilityStatement into their capabilities as described below. A server that certifies to the 21st Century Cures Act for accessing patient data must implement all components in the IECDI and the IE Core CapabilityStatement.
A conformant server:
SHOULD declare conformance with the IE Core Server Capability Statement by including its official URL in the server's CapabilityStatement.instantiates element: http://iehr.ai/fhir/ie/core/CapabilityStatement/ie-core-server
CapabilityStatement.rest.resource.supportedProfile element.
Example CapabilityStatement snippet for a server conforming to the IE Core Patient Profile:
{
"resourceType": "CapabilityStatement",
...
"instantiates": [
"http://iehr.ai/fhir/ie/core/CapabilityStatement/ie-core-server"
],
...
"rest": [
{
"mode": "server",
...
"resource": [
...
{
[
{
"extension": [
{
"url": "required",
"valueString": "birthdate"
},
{
"url": "required",
"valueString": "name"
}
],
"url": "http://hl7.org/fhir/StructureDefinition/capabilitystatement-search-parameter-combination"
},
{
"extension": [
{
"url": "required",
"valueString": "family"
},
{
"url": "required",
"valueString": "gender"
}
],
"url": "http://hl7.org/fhir/StructureDefinition/capabilitystatement-search-parameter-combination"
},
{
{
"url": "required",
"valueString": "birthdate"
},
{
"url": "required",
"valueString": "family"
}
],
"url": "http://hl7.org/fhir/StructureDefinition/capabilitystatement-search-parameter-combination"
},
{
"extension": [
{
"url": "required",
"valueString": "gender"
},
{
"url": "required",
"valueString": "name"
}
],
"url": "http://hl7.org/fhir/StructureDefinition/capabilitystatement-search-parameter-combination"
}
]
}
]
"type": "Patient",
"supportedProfile": [
"http://iehr.ai/fhir/ie/core/StructureDefinition/ie-core-patient"
],
"interaction": [
{
"code": "create"
},
{
"code": "search-type"
},
{
"code": "read"
}
],
"referencePolicy": [
"resolves"
],
"searchRevInclude": [
"Provenance:target"
],
"searchParam": [
{
"name": "_id",
"definition": "http://iehr.ai/fhir/ie/core/SearchParameter/ie-core-patient-id",
"type": "token"
},
{
"name": "identifier",
"definition": "http://iehr.ai/fhir/ie/core/SearchParameter/ie-core-patient-identifier",
"type": "token",
"documentation": "The client **SHALL** provide at least a code value and **MAY** provide both the system and code values.\n\nThe server **SHALL** support both."
},
{
"name": "name",
"definition": "http://iehr.ai/fhir/ie/core/SearchParameter/ie-core-patient-name",
"type": "string"
}
],
...
}
]
}
]
}
The following rules summarize the requirements defined by FHIR Terminology for coded elements (CodeableConcept, Coding, and code datatypes).
Required binding to a ValueSet definition means that one of the codes from the specified ValueSet SHALL be used. For CodeableConcept, which permits multiple codings and a text element, this rule applies to at least one of the codings, and only text is not valid.
For example, the IE Core AllergyIntolerance Profile clinicalStatus element has a required binding to the IECoreAllergyIntoleranceClinicalStatus ValueSet. Therefore, when claiming conformance to this profile:
AllergyIntolerance.clinicalStatus.code.AllergyIntolerance.clinicalStatus.code.Because of the FHIR conformance rule:
If an extensible binding is applied to an element with maximum cardinality > 1, the binding applies to all the elements. (Terminology Binding Extensible)
FHIR profiles use slicing when a coded element is a repeating element, and a particular ValueSet is desired for at least one of the repeats. This is a special case where a required ValueSet binding is used to differentiate the repeat. In this guide, the minimum cardinality for these 'slices' is set to 0 so that other codes are allowed when no suitable code exists in the ValueSet (equivalent to Extensible Binding below). Note that slicing by valueset does not affect the over the wire structure or validation of instances of these resources. The example in Figure 2 below illustrates this structure for the repeating DocumentReference.category element:
Extensible Binding means that one of the codes from the specified ValueSet SHALL be used if an applicable concept is present. If no suitable code exists in the ValueSet, alternate code(s) may be provided. For CodeableConcept, which permits multiple codings and a text element, this rule applies to at least one of the codings. If only text is available and it has no conceptual overlap with the bound coded values, then just text may be used.
The IE Core AllergyIntolerance Profile illustrates the extensible binding rules for the CodeableConcept datatype. The AllergyIntolerance.code element has an extensible binding to the IE Core Vaccines ValueSet "Common substances for allergy and intolerance documentation including refutations" Allergy. When claiming conformance to this profile:
AllergyIntolerance.code.code if the concept exists in the ValueSetAllergyIntolerance.code.code or text in AllergyIntolerance.code.textThe FHIR rules for extensible bindings state that all conceptual overlaps, including free text, should be mapped to the coded values in the bindings. IE Core adopts the current additional binding from FHIR R5 for more flexibility in exchanging legacy and text-only data. The current binding requires newly recorded, non-legacy data to be drawn from the value set.
For example, the IE Core Procedure Codes and IE Core Condition Codes ValueSets cover the entire domain. For data not captured by fine-grained code, it is possible to provide a high-level abstract code, such as SNOMED CT "Procedure". Therefore, instead of requiring systems to map all legacy and text data to standard codes, the value set uses a "current" binding
The "current" binding corresponds to the IE Core's interpretation of extensible bindings IE Core version 0.1.0 and earlier.
Alternate codes may be provided in addition to the standard codes defined in required or extensible ValueSets. These alternate codes are called "translations". They may be equivalent to or narrower in meaning than the standard concept code.
Example of multiple translations for Body Weight concept code.
"code": {
"coding": [
{
"system": "http://loinc.org", //NOTE: this is the standard concept defined in the ValueSet//
"code": "29463-7",
"display": "Body Weight"
},
//NOTE: this is a translation to a more specific concept
{
"system": "http://loinc.org",
"code": "3141-9",
"display": "Body Weight Measured"
},
//NOTE: this is a translation to a different code system (Snomed CT)
{
"system": "http://snomed.info/sct",
"code": "364589006",
"display": "Body Weight"
}
//NOTE: this is a translation to a locally defined code
{
"system": "http://AcmeHealthCare.org",
"code": "BWT",
"display": "Body Weight"
}
],
"text": "weight"
},
A FHIR modifier element is an element that modifies the meaning of a resource element. Although servers and clients SHALL be able to process Mandatory or Must Support elements, not all modifier elements are Mandatory or Must Support, and there is no requirement for supporting them. Therefore, FHIR clients need to be aware of unexpected modifier elements in the data they receive because they can alter the meaning of the data and can potentially lead to errors or even security risks if not properly handled. In addition, modifiers can be introduced when the data is created, edited, or transmitted, so it is crucial to ensure that all modifiers are understood and handled correctly.
In addition to declaring which IE Core profiles they support, Servers MAY communicate a system-wide profile in their CapabilityStatement to identify which additional elements, including modifier elements, they support. However, systems are free to include other data elements - and receivers SHOULD accept instances that even contain unexpected data elements except when those elements are modifier elements. Unless a client determines they can process it safely, rejection is typically the only safe action if unexpected modifier elements are present. For example, an app or system may process modifier elements nested inside an ignored element or in a resource only for human review.
Some examples of modifiers that are not Must Support elements in IE Core Profiles include:
implicitRules element common to all profilesmodifierExtension element common to all profilesObservation.value[x].comparatorPractitioner.identifier.usePatient.activeImplementers SHOULD review the "Key Elements Tab" on the IE Core profile pages. This view lists all the Must Support and modifier elements for a profil.
There are situations when information on a particular data element is missing, and the source system does not know the reason for the absence of data. If the source system does not have data for an element with a minimum cardinality = 0 (including elements labeled Must Support), the data element SHALL be omitted from the resource. However, if the data element is a Mandatory element (in other words, where the minimum cardinality is > 0), it SHALL be present even if the source system does not have data. The core specification guides what to do in this situation, which is summarized below:
unknown - The value is expected to exist but is not known.Example: Patient resource where the patient name is not available.
{
"resourceType": "Patient",
...
"name": [
{
"extension": [
{
"url": "http://hl7.org/fhir/StructureDefinition/data-absent-reason",
"valueCode": "unknown"
}
]
}
]
"telecom":
...
}
text element is used.
display element.unknown from the DataAbsentReason Code System.Example: CareTeam resource where the mandatory CareTeam.participant.role value is unknown.
...
"participant": [
{
"role": [
{
"coding": [
{
"url": "http://hl7.org/fhir/StructureDefinition/data-absent-reason",
"code": "unknown",
"display": "unknown"
}
]
}
],
"member": {
"reference": "Practitioner/practitioner-1",
"display": "Ronald Bone, MD"
}
},
...
if the ValueSet does not have the appropriate "unknown" concept code, you must use a concept from the ValueSet. Otherwise, the instance will not be conformant
AllergyIntolerance.clinicalStatus*Condition.clinicalStatus*DocumentReference.statusImmunization.statusGoal.lifecycleStatus*The clinicalStatus element is conditionally mandatory based on resource-specific constraints.
If any of these status codes is missing, a 404 HTTP error code and an OperationOutcome SHALL be returned in response to a read transaction on the resource. If returning a response to a search, the problematic resource SHALL be excluded from the search set, and a warning OperationOutcome SHOULD be included indicating that other search results were found but could not be compliantly expressed and have been suppressed.
The FHIR RESTful Search API requires that servers that support search SHALL support the HTTP POST-based search. For all the supported search interactions in this guide, servers SHALL also support the GET-based search.
token type searchparameter (how to search by token)
reference type searchparameter (how to search by reference)
date type searchparameter (how to search by date):
date and to the second + time offset for elements of datatype dateTime.date and to the second + time offset for elements of datatype dateTime.The table below summarizes the date precision:
| SearchParameter | Element Datatype | Minimum Date Precision | Example |
|---|---|---|---|
| date | date | day | GET [base]/Patient?family=Shaw&birthdate=2007-03-20 |
| date | dateTime, Period | second + time offset | GET [base]Observation?patient=555580&category=laboratory&date=ge2018-03-14T00:00:00-08:00 |
Servers are strongly encouraged to support a query for resources without requiring a status parameter. However, if business requirements prohibit this, they SHALL follow the guidelines here.
For searches where the client does not supply a status parameter, an implementation's business rules may override the FHIR RESTful search expectations and require a status parameter to be provided. These systems are allowed to reject such requests as follows:
400 statusIf a system doesn't support a specific status code value that is queried, it SHOULD return an HTTP 200 status with a search bundle. The search bundle SHOULD contain resources matching the search criteria and an OperationOutcome warning the client which status code value is not supported.
For example, in a query enumerating all the AllergyIntolerance.verificationStatus statuses to a system that supports concepts unconfirmed, confirmed, and entered-in-error but not the concept refuted, the search parameter refers to an unsupported code since refuted is not known to the server.
Storyboard for this example
This example is based upon the following scenario:
Patient 1137192 uses an App to request all his encounters from the provider. The provider system requires status and rejects the request returning a 400 and an OperationOutcome specifying that a status parameter is required for this search.
Request:
Get “all encounters” for a patient 1137192 by querying Encounter using the patient search parameter.
GET [base]/Encounter?patient=1137192
Response:
Instead of returning a search Bundle resource containing all the Encounter for the patient, the server return a 400 Not Found and an OperationOutcome detailing that a status parameter is required for this search.
HTTP/1.1 400 Not Found
[other headers]
{
"resourceType": "OperationOutcome",
"id": "no-status",
"issue": [
{
"severity": "error",
"code": "business-rule",
"details": {
"text": "A \"status\" search parameter is required for this search"
},
"diagnostics": "valid statuses for Encounter include planned | arrived | triaged | in-progress | onleave | finished | cancelled | entered-in-error | unknown"
}
]
}
CapabilityStatement.rest.resource.interaction.documentation.