CH Core (R4)
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CH Core (R4), published by HL7 Switzerland. This guide is not an authorized publication; it is the continuous build for version 5.0.0-ci-build built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/hl7ch/ch-core/ and changes regularly. See the Directory of published versions

Data Type Profile: CHCoreQuantityWithEmedUnits - Detailed Descriptions

Active as of 2024-11-20

Definitions for the ch-core-quantity-with-emed-units data type profile.

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

0. Quantity
2. Quantity.value
Control1..?
4. Quantity.unit
Control1..?
6. Quantity.system
Control1..?
8. Quantity.code
Control1..?
BindingThe codes SHOULD be taken from UnitCode
(preferred to http://fhir.ch/ig/ch-term/ValueSet/UnitCode)

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

0. Quantity
Definition

The comparator is not used on a SimpleQuantity


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.

ShortA fixed quantity (no comparator)A measured or measurable amount
Comments

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.

Control0..*
This element is affected by the following invariants: ele-1
Is Modifierfalse
Invariantsele-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.value
Definition

The value of the measured amount. The value includes an implicit precision in the presentation of the value.

ShortNumerical value (with implicit precision)
Comments

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).

Control10..1
Typedecimal
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
Requirements

Precision is handled implicitly in almost all cases of measurement.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
4. Quantity.comparator
Definition

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
Control0..01
BindingThe codes SHALL be taken from QuantityComparatorhttp://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.

Typecode
Is Modifiertrue 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 ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
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 MissingIf there is no comparator, then there is no modification of the value
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
6. Quantity.unit
Definition

A human-readable form of the unit.

ShortUnit representation
Control10..1
Typestring
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
Requirements

There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
8. Quantity.system
Definition

The identification of the system that provides the coded form of the unit.

ShortSystem that defines coded unit form
Control10..1
This element is affected by the following invariants: qty-3
Typeuri
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
Requirements

Need to know the system that defines the coded form of the unit.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
10. Quantity.code
Definition

A computer processable form of the unit in some unit representation system.

ShortCoded form of the unit
Comments

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.

Control10..1
BindingThe codes SHOULD be taken from For codes, see UnitCode
(preferred to http://fhir.ch/ig/ch-term/ValueSet/UnitCode)
Typecode
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
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.

Invariantsele-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 found here

0. Quantity
Definition

The comparator is not used on a SimpleQuantity

ShortA fixed quantity (no comparator)
Comments

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.

Control0..*
This element is affected by the following invariants: ele-1
Is Modifierfalse
Invariantsele-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
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

ShortUnique id for inter-element referencing
Control0..1
Typestring
Is Modifierfalse
XML FormatIn the XML format, this property is represented as an attribute.
Summaryfalse
4. Quantity.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.

ShortAdditional 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.

Control0..*
TypeExtension
Is Modifierfalse
Summaryfalse
Alternate Namesextensions, user content
Invariantsele-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())
SlicingThis 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
    Definition

    The value of the measured amount. The value includes an implicit precision in the presentation of the value.

    ShortNumerical value (with implicit precision)
    Comments

    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).

    Control1..1
    Typedecimal
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Requirements

    Precision is handled implicitly in almost all cases of measurement.

    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    8. Quantity.comparator
    Definition

    Not allowed to be used in this context

    Short< | <= | >= | > - how to understand the value
    Control0..0
    BindingThe 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.

    Typecode
    Is Modifiertrue 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 ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    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 MissingIf there is no comparator, then there is no modification of the value
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    10. Quantity.unit
    Definition

    A human-readable form of the unit.

    ShortUnit representation
    Control1..1
    Typestring
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Requirements

    There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    12. Quantity.system
    Definition

    The identification of the system that provides the coded form of the unit.

    ShortSystem that defines coded unit form
    Control1..1
    This element is affected by the following invariants: qty-3
    Typeuri
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Requirements

    Need to know the system that defines the coded form of the unit.

    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    14. Quantity.code
    Definition

    A computer processable form of the unit in some unit representation system.

    ShortCoded form of the unit
    Comments

    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.

    Control1..1
    BindingThe codes SHOULD be taken from UnitCode
    (preferred to http://fhir.ch/ig/ch-term/ValueSet/UnitCode)
    Typecode
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    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.

    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))