Data Management with FHIR
0.1.0 - ci-build

Data Management with FHIR - Local Development build (v0.1.0) built by the FHIR (HL7® FHIR® Standard) Build Tools. See the Directory of published versions

## Data Type Profile: FrSimpleQuantityUcum - Detailed Descriptions

Draft as of 2025-10-23

Definitions for the FrSimpleQuantityUcum 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. Quantity
Définition | The comparator is not used on a SimpleQuantity. The unit SHALL be a UCUM code. A measured amount (or an amount that can potentially be measured). Note that measured amounts include amounts that are not precisely quantified, including amounts involving arbitrary units and floating currencies.
Short | A fixed quantity (no comparator) with UCUM unitA measured or measurable amount
Commentaires | The context of use may frequently define what kind of quantity this is and therefore what kind of units can be used. The context of use explicitely excludes the use of the simpleQuantity "comparator" element. The context of use may frequently define what kind of quantity this is and therefore what kind of units can be used. The context of use may also restrict the values for the comparator.
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())) qty-3: If a code for the unit is present, the system SHALL also be present (`code.empty() or system.exists()`) sqty-1: The comparator is not used on a SimpleQuantity (`comparator.empty()`) qty-3: If a code for the unit is present, the system SHALL also be present (code.empty() or system.exists())
2. Quantity.comparator
Définition | Not allowed to be used in this context How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.
Short | < | <= | >= | > - how to understand the value
Control | 0..01
Binding | The codes SHALL be taken from QuantityComparator http://hl7.org/fhir/ValueSet/quantity-comparator|4.0.1 (required to `http://hl7.org/fhir/ValueSet/quantity-comparator|4.0.1` ) How the Quantity should be understood and represented.
Type | code
Is Modifier | true because This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Résumé | true
Requirements | Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.
Meaning if Missing | If there is no comparator, then there is no modification of the value
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
4. Quantity.system
Définition | UCUM requiered for the identification of the system that provides the coded form of the unit. The identification of the system that provides the coded form of the unit.
Short | System that defines coded unit form
Control | 10..1 This element is affected by the following invariants: qty-3
Type | uri
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | true
Résumé | true
Requirements | UCUM requiered. Need to know the system that defines the coded form of the unit.
Fixed Value | `http://unitsofmeasure.org`
Invariants | ele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
6. Quantity.code
Définition | A computer processable form of the unit in some unit representation system.
Short | Coded form of the unit
Commentaires | UCUM code required. The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency. The context of use may additionally require a code from a particular system.
Control | 10..1
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | true
Résumé | true
Requirements | Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.
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. Quantity
Définition | The comparator is not used on a SimpleQuantity. The unit SHALL be a UCUM code.
Short | A fixed quantity (no comparator) with UCUM unit
Commentaires | The context of use may frequently define what kind of quantity this is and therefore what kind of units can be used. The context of use explicitely excludes the use of the simpleQuantity "comparator" element.
2. Quantity.system
Définition | UCUM requiered for the identification of the system that provides the coded form of the unit.
Control | 1..?
Must Support | true
Requirements | UCUM requiered.
Fixed Value | `http://unitsofmeasure.org`
4. Quantity.code
Commentaires | UCUM code required.
Control | 1..?
Must Support | true

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

0. Quantity
Définition | The comparator is not used on a SimpleQuantity. The unit SHALL be a UCUM code.
Short | A fixed quantity (no comparator) with UCUM unit
Commentaires | The context of use may frequently define what kind of quantity this is and therefore what kind of units can be used. The context of use explicitely excludes the use of the simpleQuantity "comparator" element.
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())`) qty-3: If a code for the unit is present, the system SHALL also be present (`code.empty() or system.exists()`) sqty-1: The comparator is not used on a SimpleQuantity (`comparator.empty()`)
2. Quantity.id
Définition | 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.
Résumé | false
4. Quantity.extension
Définition | 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
Commentaires | 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
Résumé | 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 `Quantity.extension`. The slices areUnordered and Open, and can be differentiated using the following discriminators: value @ url
6. Quantity.value
Définition | The value of the measured amount. The value includes an implicit precision in the presentation of the value.
Short | Numerical value (with implicit precision)
Commentaires | The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).
Control | 0..1
Type | decimal
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Résumé | true
Requirements | Precision is handled implicitly in almost all cases of measurement.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
8. Quantity.comparator
Définition | Not allowed to be used in this context
Short | < | <= | >= | > - how to understand the value
Control | 0..0
Binding | The codes SHALL be taken from QuantityComparator (required to `http://hl7.org/fhir/ValueSet/quantity-comparator|4.0.1` ) How the Quantity should be understood and represented.
Type | code
Is Modifier | true because This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Résumé | true
Requirements | Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.
Meaning if Missing | If there is no comparator, then there is no modification of the value
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
10. Quantity.unit
Définition | A human-readable form of the unit.
Short | Unit representation
Control | 0..1
Type | string
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Résumé | true
Requirements | There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
12. Quantity.system
Définition | UCUM requiered for the identification of the system that provides the coded form of the unit.
Short | System that defines coded unit form
Control | 1..1 This element is affected by the following invariants: qty-3
Type | uri
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | true
Résumé | true
Requirements | UCUM requiered.
Fixed Value | `http://unitsofmeasure.org`
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)
14. Quantity.code
Définition | A computer processable form of the unit in some unit representation system.
Short | Coded form of the unit
Commentaires | UCUM code required.
Control | 1..1
Type | code
Is Modifier | false
Primitive Value | This primitive element may be present, or absent, or replaced by an extension
Must Support | true
Résumé | true
Requirements | Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.
Invariants | ele-1: All FHIR elements must have a @value or children (`hasValue() or (children().count() > id.count())`)