HL7 FHIR Implementation Guide: Transversal Clinical Core
1.0.1 - STU1

HL7 FHIR Implementation Guide: Transversal Clinical Core, published by eHealth Platform. This guide is not an authorized publication; it is the continuous build for version 1.0.1 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/hl7-be/core-clinical/ and changes regularly. See the Directory of published versions

## Data Type Profile: BeObservationCodeableConcept - Detailed Descriptions

Active as of 2025-10-16 | Maturity Level: 1

Definitions for the be-observationcodeableconcept data type profile.

- Key Elements Table
- Differential Elements Table
- Snapshot Elements Table

Guidance on how to interpret the contents of this table can be foundhere

0. CodeableConcept
Definition | A concept that may be defined by a formal reference to a terminology or ontology or may be provided by text.
Short | Concept - reference to a terminology or just text
Comments | Not all terminology uses fit this general pattern. In some cases, models should not use CodeableConcept and use Coding directly and provide their own structure for managing text, codings, translations and the relationship between elements and pre- and post-coordination.
Control | 0..* This element is affected by the following invariants: ele-1
Is Modifier | false
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
2. CodeableConcept.coding
Definition | A reference to a code defined by a terminology system.
Short | Code defined by a terminology system
Comments | Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Control | 0..*
Type | Coding
Is Modifier | false
Summary | true
Requirements | Allows for alternative encodings within a code system, and translations to other code systems.
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
Slicing | This element introduces a set of slices on `CodeableConcept.coding`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ system
4. CodeableConcept.coding:LOINC
Slice Name | LOINC
Definition | A reference to a code defined by a terminology system.
Short | Code defined by a terminology system
Comments | Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Control | 0..*
Type | Coding
Is Modifier | false
Summary | true
Requirements | Allows for alternative encodings within a code system, and translations to other code systems.
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
6. CodeableConcept.coding:LOINC.system
Definition | The identification of the code system that defines the meaning of the symbol in the code.
Short | Identity of the terminology system
Comments | The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.
Control | 10..1
Type | uri
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to be unambiguous about the source of the definition of the symbol.
Fixed Value | `http://loinc.org`
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
8. CodeableConcept.coding:LOINC.code
Definition | A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Short | Symbol in syntax defined by the system
Control | 10..1
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to refer to a particular code in the system.
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
10. CodeableConcept.coding:SNOMED-CT
Slice Name | SNOMED-CT
Definition | A reference to a code defined by a terminology system.
Short | Code defined by a terminology system
Comments | Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Control | 0..*
Type | Coding
Is Modifier | false
Summary | true
Requirements | Allows for alternative encodings within a code system, and translations to other code systems.
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
12. CodeableConcept.coding:SNOMED-CT.system
Definition | The identification of the code system that defines the meaning of the symbol in the code.
Short | Identity of the terminology system
Comments | The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.
Control | 10..1
Type | uri
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to be unambiguous about the source of the definition of the symbol.
Fixed Value | `http://snomed.info/sct`
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
14. CodeableConcept.coding:SNOMED-CT.code
Definition | A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Short | Symbol in syntax defined by the system
Control | 10..1
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to refer to a particular code in the system.
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))

Guidance on how to interpret the contents of this table can be foundhere

0. CodeableConcept
2. CodeableConcept.coding
Slicing | This element introduces a set of slices on `CodeableConcept.coding`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ system
4. CodeableConcept.coding:LOINC
Slice Name | LOINC
Control | 0..*
6. CodeableConcept.coding:LOINC.system
Control | 1..?
Fixed Value | `http://loinc.org`
8. CodeableConcept.coding:LOINC.code
Control | 1..?
10. CodeableConcept.coding:SNOMED-CT
Slice Name | SNOMED-CT
Control | 0..*
12. CodeableConcept.coding:SNOMED-CT.system
Control | 1..?
Fixed Value | `http://snomed.info/sct`
14. CodeableConcept.coding:SNOMED-CT.code
Control | 1..?

Guidance on how to interpret the contents of this table can be foundhere

0. CodeableConcept
Definition | A concept that may be defined by a formal reference to a terminology or ontology or may be provided by text.
Short | Concept - reference to a terminology or just text
Comments | Not all terminology uses fit this general pattern. In some cases, models should not use CodeableConcept and use Coding directly and provide their own structure for managing text, codings, translations and the relationship between elements and pre- and post-coordination.
Control | 0..* This element is affected by the following invariants: ele-1
Is Modifier | false
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
2. CodeableConcept.id
Definition | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.
Short | Unique id for inter-element referencing
Control | 0..1
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
4. CodeableConcept.extension
Definition | May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.
Short | Additional content defined by implementations
Comments | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.
Control | 0..*
Type | Extension
Is Modifier | false
Summary | false
Alternate Names | extensions, user content
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
Slicing | This element introduces a set of slices on `CodeableConcept.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
6. CodeableConcept.coding
Definition | A reference to a code defined by a terminology system.
Short | Code defined by a terminology system
Comments | Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Control | 0..*
Type | Coding
Is Modifier | false
Summary | true
Requirements | Allows for alternative encodings within a code system, and translations to other code systems.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
Slicing | This element introduces a set of slices on `CodeableConcept.coding`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ system
8. CodeableConcept.coding:LOINC
Slice Name | LOINC
Definition | A reference to a code defined by a terminology system.
Short | Code defined by a terminology system
Comments | Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Control | 0..*
Type | Coding
Is Modifier | false
Summary | true
Requirements | Allows for alternative encodings within a code system, and translations to other code systems.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
10. CodeableConcept.coding:LOINC.id
Definition | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.
Short | Unique id for inter-element referencing
Control | 0..1
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
12. CodeableConcept.coding:LOINC.extension
Definition | May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.
Short | Additional content defined by implementations
Comments | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.
Control | 0..*
Type | Extension
Is Modifier | false
Summary | false
Alternate Names | extensions, user content
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
Slicing | This element introduces a set of slices on `CodeableConcept.coding.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
14. CodeableConcept.coding:LOINC.system
Definition | The identification of the code system that defines the meaning of the symbol in the code.
Short | Identity of the terminology system
Comments | The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.
Control | 1..1
Type | uri
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to be unambiguous about the source of the definition of the symbol.
Fixed Value | `http://loinc.org`
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
16. CodeableConcept.coding:LOINC.version
Definition | The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Short | Version of the system - if relevant
Comments | Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Note | This is a business version Id, not a resource version Id (see discussion)
Control | 0..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
18. CodeableConcept.coding:LOINC.code
Definition | A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Short | Symbol in syntax defined by the system
Control | 1..1
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to refer to a particular code in the system.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
20. CodeableConcept.coding:LOINC.display
Definition | A representation of the meaning of the code in the system, following the rules of the system.
Short | Representation defined by the system
Control | 0..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
22. CodeableConcept.coding:LOINC.userSelected
Definition | Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Short | If this coding was chosen directly by the user
Comments | Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Control | 0..1
Type | boolean
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
24. CodeableConcept.coding:SNOMED-CT
Slice Name | SNOMED-CT
Definition | A reference to a code defined by a terminology system.
Short | Code defined by a terminology system
Comments | Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.
Control | 0..*
Type | Coding
Is Modifier | false
Summary | true
Requirements | Allows for alternative encodings within a code system, and translations to other code systems.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
26. CodeableConcept.coding:SNOMED-CT.id
Definition | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.
Short | Unique id for inter-element referencing
Control | 0..1
Type | string
Is Modifier | false
XML Format | In the XML format, this property is represented as an attribute.
Summary | false
28. CodeableConcept.coding:SNOMED-CT.extension
Definition | May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.
Short | Additional content defined by implementations
Comments | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.
Control | 0..*
Type | Extension
Is Modifier | false
Summary | false
Alternate Names | extensions, user content
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`) ext-1: Must have either extensions or value[x], not both (`extension.exists() != value.exists()`)
Slicing | This element introduces a set of slices on `CodeableConcept.coding.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
30. CodeableConcept.coding:SNOMED-CT.system
Definition | The identification of the code system that defines the meaning of the symbol in the code.
Short | Identity of the terminology system
Comments | The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.
Control | 1..1
Type | uri
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to be unambiguous about the source of the definition of the symbol.
Fixed Value | `http://snomed.info/sct`
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
32. CodeableConcept.coding:SNOMED-CT.version
Definition | The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.
Short | Version of the system - if relevant
Comments | Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.
Note | This is a business version Id, not a resource version Id (see discussion)
Control | 0..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
34. CodeableConcept.coding:SNOMED-CT.code
Definition | A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).
Short | Symbol in syntax defined by the system
Control | 1..1
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to refer to a particular code in the system.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
36. CodeableConcept.coding:SNOMED-CT.display
Definition | A representation of the meaning of the code in the system, following the rules of the system.
Short | Representation defined by the system
Control | 0..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | Need to be able to carry a human-readable meaning of the code for readers that do not know the system.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
38. CodeableConcept.coding:SNOMED-CT.userSelected
Definition | Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).
Short | If this coding was chosen directly by the user
Comments | Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.
Control | 0..1
Type | boolean
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
40. CodeableConcept.text
Definition | A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.
Short | Plain text representation of the concept
Comments | Very often the text is the same as a displayName of one of the codings.
Control | 0..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Summary | true
Requirements | The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)