# text.div
Generated Narrative: StructureDefinition DP-Quantity-1

Name | Flags | Card. | Type | Description & Constraints

Quantity

C

0..*

Quantity

A measured or measurable amount
Constraints: ksa-qty-1

value | | 1..1 | DP_decimal | Numerical value (with implicit precision)

unit

S

0..1

string

Unit representation
Max Length: 40

system | S | 0..1 | DP_uri | System that defines coded unit form
code | S | 0..1 | DP_code | Coded form of the unit

Documentation for this format

# description
Quantity datatype which only requires a value.

# snapshot.element[].definition
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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
If a code for the unit is present, the system SHALL also be present

# snapshot.element[].constraint[].human
May provide units as either as text or system and code

# snapshot.element[].mapping[].map
PQ, IVL<PQ>, MO, CO, depending on the values

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

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional content defined by implementations

# snapshot.element[].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.

# snapshot.element[].comment
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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Numerical value (with implicit precision)

# snapshot.element[].definition
The value of the measured amount. The value includes an implicit precision in the presentation of the value.

# snapshot.element[].comment
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).

# snapshot.element[].requirements
Precision is handled implicitly in almost all cases of measurement.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].mapping[].map
PQ.value, CO.value, MO.value, IVL.high or IVL.low depending on the value

# snapshot.element[].short
< | <= | >= | > - how to understand the value

# snapshot.element[].definition
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.

# snapshot.element[].requirements
Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

# snapshot.element[].meaningWhenMissing
If there is no comparator, then there is no modification of the value

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].isModifierReason
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

# snapshot.element[].binding.description
How the Quantity should be understood and represented.

# snapshot.element[].requirements
There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
The identification of the system that provides the coded form of the unit.

# snapshot.element[].requirements
Need to know the system that defines the coded form of the unit.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# snapshot.element[].definition
A computer processable form of the unit in some unit representation system.

# snapshot.element[].comment
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.

# snapshot.element[].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.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() or (children().count() > id.count())

# differential.element[].constraint[].human
May provide units as either as text or system and code