Da Vinci Prior Authorization Support (PAS) FHIR IG
2.1.0 - STU 2.1 United States of America flag

This page is part of the Da Vinci Prior Authorization Support (PAS) FHIR IG (v2.1.0: STU 2) based on FHIR (HL7® FHIR® Standard) R4. This is the current published version. For a full list of available versions, see the Directory of published versions

Data Type Profile: PASQuantity - XML Profile

Page standards status: Trial-use Maturity Level: 3

XML representation of the profile-quantity data type profile.

Raw xml | Download


<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="profile-quantity"/>
  <text>
    <status value="extensions"/>
    <div xmlns="http://www.w3.org/1999/xhtml"><p class="res-header-id"><b>Generated Narrative: StructureDefinition profile-quantity</b></p><a name="profile-quantity"> </a><a name="hcprofile-quantity"> </a><a name="profile-quantity-en-US"> </a><table border="0" cellpadding="0" cellspacing="0" style="border: 0px #F0F0F0 solid; font-size: 11px; font-family: verdana; vertical-align: top;"><tr style="border: 1px #F0F0F0 solid; font-size: 11px; font-family: verdana; vertical-align: top"><th style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="The logical name of the element">Name</a></th><th style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Information about the use of the element">Flags</a></th><th style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Minimum and Maximum # of times the element can appear in the instance">Card.</a></th><th style="width: 100px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Reference to the type of the element">Type</a></th><th style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Additional information about the element">Description &amp; Constraints</a><span style="float: right"><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Legend for this format"><img src="data:image/png;base64,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" alt="doco" style="background-color: inherit"/></a></span></th></tr><tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white"><td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck1.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="icon_element.gif" alt="." style="background-color: white; background-color: inherit" title="Element" class="hierarchy"/> <a href="StructureDefinition-profile-quantity-definitions.html#Quantity">Quantity</a><a name="Quantity"> </a></td><td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="http://hl7.org/fhir/R4/datatypes.html#SimpleQuantity">SimpleQuantity</a></td><td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/></tr>
<tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: #F7F7F7"><td style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck00.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_vjoin_end.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="icon_element.gif" alt="." style="background-color: #F7F7F7; background-color: inherit" title="Element" class="hierarchy"/> <a href="StructureDefinition-profile-quantity-definitions.html#Quantity.code">code</a><a name="Quantity.code"> </a></td><td style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><span style="opacity: 0.5">0</span><span style="opacity: 0.5">..</span><span style="opacity: 0.5">1</span></td><td style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a style="opacity: 0.5" href="http://hl7.org/fhir/R4/datatypes.html#code">code</a></td><td style="vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><span style="opacity: 0.5">Coded form of the unit</span><br/><span style="font-weight:bold">Binding: </span><a href="https://valueset.x12.org/x217/005010/request/2000F/HSD/1/01/00/673">https://valueset.x12.org/x217/005010/request/2000F/HSD/1/01/00/673</a> (<a href="http://hl7.org/fhir/R4/terminologies.html#required" title="To be conformant, the concept in this element SHALL be from the specified value set.">required</a>)</td></tr>
<tr><td colspan="5" class="hierarchy"><br/><a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Legend for this format"><img src="data:image/png;base64,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" alt="doco" style="background-color: inherit"/> Documentation for this format</a></td></tr></table></div>
  </text>
  <extension
             url="http://hl7.org/fhir/StructureDefinition/structuredefinition-wg">
    <valueCode value="fm"/>
  </extension>
  <extension
             url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm">
    <valueInteger value="3">
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom">
        <valueCanonical
                        value="http://hl7.org/fhir/us/davinci-pas/ImplementationGuide/hl7.fhir.us.davinci-pas"/>
      </extension>
    </valueInteger>
  </extension>
  <extension
             url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
    <valueCode value="trial-use">
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom">
        <valueCanonical
                        value="http://hl7.org/fhir/us/davinci-pas/ImplementationGuide/hl7.fhir.us.davinci-pas"/>
      </extension>
    </valueCode>
  </extension>
  <url
       value="http://hl7.org/fhir/us/davinci-pas/StructureDefinition/profile-quantity"/>
  <identifier>
    <system value="urn:ietf:rfc:3986"/>
    <value value="urn:oid:2.16.840.1.113883.4.642.40.24.42.70"/>
  </identifier>
  <version value="2.1.0"/>
  <name value="PASQuantity"/>
  <title value="PAS Quantity"/>
  <status value="active"/>
  <date value="2024-12-20T21:49:30+00:00"/>
  <publisher value="HL7 International / Financial Management"/>
  <contact>
    <name value="HL7 International / Financial Management"/>
    <telecom>
      <system value="url"/>
      <value value="http://hl7.org/Special/committees/fm"/>
    </telecom>
    <telecom>
      <system value="email"/>
      <value value="fmlists@lists.hl7.org"/>
    </telecom>
  </contact>
  <contact>
    <name value="Jean Duteau"/>
    <telecom>
      <system value="email"/>
      <value value="mailto:jean@duteaudesign.com"/>
    </telecom>
  </contact>
  <contact>
    <name value="HL7 International / Financial Management"/>
    <telecom>
      <system value="url"/>
      <value value="http://www.hl7.org/Special/committees/fm"/>
    </telecom>
  </contact>
  <description
               value="Constraints and extensions on SimpleQuantity which restricts the units."/>
  <jurisdiction>
    <coding>
      <system value="urn:iso:std:iso:3166"/>
      <code value="US"/>
      <display value="United States of America"/>
    </coding>
  </jurisdiction>
  <fhirVersion value="4.0.1"/>
  <mapping>
    <identity value="v2"/>
    <uri value="http://hl7.org/v2"/>
    <name value="HL7 v2 Mapping"/>
  </mapping>
  <mapping>
    <identity value="rim"/>
    <uri value="http://hl7.org/v3"/>
    <name value="RIM Mapping"/>
  </mapping>
  <kind value="complex-type"/>
  <abstract value="false"/>
  <type value="Quantity"/>
  <baseDefinition
                  value="http://hl7.org/fhir/StructureDefinition/SimpleQuantity"/>
  <derivation value="constraint"/>
  <snapshot>
    <element id="Quantity">
      <path value="Quantity"/>
      <short value="A fixed quantity (no comparator)"/>
      <definition value="The comparator is not used on a SimpleQuantity"/>
      <comment
               value="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."/>
      <min value="0"/>
      <max value="*"/>
      <base>
        <path value="Quantity"/>
        <min value="0"/>
        <max value="*"/>
      </base>
      <condition value="ele-1"/>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression
                    value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <constraint>
        <key value="qty-3"/>
        <severity value="error"/>
        <human
               value="If a code for the unit is present, the system SHALL also be present"/>
        <expression value="code.empty() or system.exists()"/>
        <xpath value="not(exists(f:code)) or exists(f:system)"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Quantity"/>
      </constraint>
      <constraint>
        <key value="sqty-1"/>
        <severity value="error"/>
        <human value="The comparator is not used on a SimpleQuantity"/>
        <expression value="comparator.empty()"/>
        <xpath value="not(exists(f:comparator))"/>
        <source
                value="http://hl7.org/fhir/StructureDefinition/SimpleQuantity"/>
      </constraint>
      <isModifier value="false"/>
      <mapping>
        <identity value="rim"/>
        <map value="n/a"/>
      </mapping>
      <mapping>
        <identity value="v2"/>
        <map value="SN (see also Range) or CQ"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="PQ, IVL&lt;PQ&gt;, MO, CO, depending on the values"/>
      </mapping>
    </element>
    <element id="Quantity.id">
      <path value="Quantity.id"/>
      <representation value="xmlAttr"/>
      <short value="Unique id for inter-element referencing"/>
      <definition
                  value="Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Element.id"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <extension
                   url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          <valueUrl value="string"/>
        </extension>
        <code value="http://hl7.org/fhirpath/System.String"/>
      </type>
      <isModifier value="false"/>
      <isSummary value="false"/>
      <mapping>
        <identity value="rim"/>
        <map value="n/a"/>
      </mapping>
    </element>
    <element id="Quantity.extension">
      <path value="Quantity.extension"/>
      <slicing>
        <discriminator>
          <type value="value"/>
          <path value="url"/>
        </discriminator>
        <description value="Extensions are always sliced by (at least) url"/>
        <rules value="open"/>
      </slicing>
      <short value="Additional content defined by implementations"/>
      <definition
                  value="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."/>
      <comment
               value="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."/>
      <alias value="extensions"/>
      <alias value="user content"/>
      <min value="0"/>
      <max value="*"/>
      <base>
        <path value="Element.extension"/>
        <min value="0"/>
        <max value="*"/>
      </base>
      <type>
        <code value="Extension"/>
      </type>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression
                    value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <constraint>
        <key value="ext-1"/>
        <severity value="error"/>
        <human value="Must have either extensions or value[x], not both"/>
        <expression value="extension.exists() != value.exists()"/>
        <xpath
               value="exists(f:extension)!=exists(f:*[starts-with(local-name(.), &quot;value&quot;)])"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Extension"/>
      </constraint>
      <isModifier value="false"/>
      <isSummary value="false"/>
      <mapping>
        <identity value="rim"/>
        <map value="n/a"/>
      </mapping>
    </element>
    <element id="Quantity.value">
      <path value="Quantity.value"/>
      <short value="Numerical value (with implicit precision)"/>
      <definition
                  value="The value of the measured amount. The value includes an implicit precision in the presentation of the value."/>
      <comment
               value="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)."/>
      <requirements
                    value="Precision is handled implicitly in almost all cases of measurement."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Quantity.value"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="decimal"/>
      </type>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression
                    value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <isModifier value="false"/>
      <isSummary value="true"/>
      <mapping>
        <identity value="v2"/>
        <map value="SN.2  / CQ - N/A"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map
             value="PQ.value, CO.value, MO.value, IVL.high or IVL.low depending on the value"/>
      </mapping>
    </element>
    <element id="Quantity.comparator">
      <path value="Quantity.comparator"/>
      <short
             value="&lt; | &lt;= | &gt;= | &gt; - how to understand the value"/>
      <definition value="Not allowed to be used in this context"/>
      <requirements
                    value="Need a framework for handling measures where the value is &lt;5ug/L or &gt;400mg/L due to the limitations of measuring methodology."/>
      <min value="0"/>
      <max value="0"/>
      <base>
        <path value="Quantity.comparator"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="code"/>
      </type>
      <meaningWhenMissing
                          value="If there is no comparator, then there is no modification of the value"/>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression
                    value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <isModifier value="true"/>
      <isModifierReason
                        value="This is labeled as &quot;Is Modifier&quot; because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value"/>
      <isSummary value="true"/>
      <binding>
        <extension
                   url="http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName">
          <valueString value="QuantityComparator"/>
        </extension>
        <strength value="required"/>
        <description
                     value="How the Quantity should be understood and represented."/>
        <valueSet
                  value="http://hl7.org/fhir/ValueSet/quantity-comparator|4.0.1"/>
      </binding>
      <mapping>
        <identity value="v2"/>
        <map value="SN.1  / CQ.1"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="IVL properties"/>
      </mapping>
    </element>
    <element id="Quantity.unit">
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/elementdefinition-translatable">
        <valueBoolean value="true"/>
      </extension>
      <path value="Quantity.unit"/>
      <short value="Unit representation"/>
      <definition value="A human-readable form of the unit."/>
      <requirements
                    value="There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Quantity.unit"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="string"/>
      </type>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression
                    value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <isModifier value="false"/>
      <isSummary value="true"/>
      <mapping>
        <identity value="v2"/>
        <map value="(see OBX.6 etc.) / CQ.2"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="PQ.unit"/>
      </mapping>
    </element>
    <element id="Quantity.system">
      <path value="Quantity.system"/>
      <short value="System that defines coded unit form"/>
      <definition
                  value="The identification of the system that provides the coded form of the unit."/>
      <requirements
                    value="Need to know the system that defines the coded form of the unit."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Quantity.system"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="uri"/>
      </type>
      <condition value="qty-3"/>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression
                    value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <isModifier value="false"/>
      <isSummary value="true"/>
      <mapping>
        <identity value="v2"/>
        <map value="(see OBX.6 etc.) / CQ.2"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="CO.codeSystem, PQ.translation.codeSystem"/>
      </mapping>
    </element>
    <element id="Quantity.code">
      <path value="Quantity.code"/>
      <short value="Coded form of the unit"/>
      <definition
                  value="A computer processable form of the unit in some unit representation system."/>
      <comment
               value="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."/>
      <requirements
                    value="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."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Quantity.code"/>
        <min value="0"/>
        <max value="1"/>
      </base>
      <type>
        <code value="code"/>
      </type>
      <constraint>
        <key value="ele-1"/>
        <severity value="error"/>
        <human value="All FHIR elements must have a @value or children"/>
        <expression
                    value="hasValue() or (children().count() &gt; id.count())"/>
        <xpath value="@value|f:*|h:div"/>
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/>
      </constraint>
      <isModifier value="false"/>
      <isSummary value="true"/>
      <binding>
        <strength value="required"/>
        <valueSet
                  value="https://valueset.x12.org/x217/005010/request/2000F/HSD/1/01/00/673"/>
      </binding>
      <mapping>
        <identity value="v2"/>
        <map value="(see OBX.6 etc.) / CQ.2"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="PQ.code, MO.currency, PQ.translation.code"/>
      </mapping>
    </element>
  </snapshot>
  <differential>
    <element id="Quantity.code">
      <path value="Quantity.code"/>
      <binding>
        <strength value="required"/>
        <valueSet
                  value="https://valueset.x12.org/x217/005010/request/2000F/HSD/1/01/00/673"/>
      </binding>
    </element>
  </differential>
</StructureDefinition>