HL7 FHIR Implementation Guide Laboratory Report
0.2.0 - trial-use

HL7 FHIR Implementation Guide Laboratory Report, published by HL7 Italia. This guide is not an authorized publication; it is the continuous build for version 0.2.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/hl7-it/lab-report/ and changes regularly. See the Directory of published versions

## Data Type Profile: QuantityLab - XML Profile

Page standards status: Trial-use | Maturity Level: 1

XML representation of the quantity-it-lab data type profile.

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    <StructureDefinition xmlns="http://hl7.org/fhir">
      <id value="quantity-it-lab"/>
      <text>
        <status value="extensions"/>
        <div xmlns="http://www.w3.org/1999/xhtml"><p class="res-header-id"><b>Generated Narrative: DefinizioneStruttura quantity-it-lab</b></p><a name="quantity-it-lab"> </a><a name="hcquantity-it-lab"> </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 : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px" 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 : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px" 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 : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px" 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="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px; 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 : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; padding-top: 3px; padding-bottom: 3px" 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, " 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 : var(--ig-left,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-quantity-it-lab-definitions.html#Quantity">Quantity</a><a name="Quantity"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a href="http://hl7.eu/fhir/laboratory/0.1.0/StructureDefinition-Quantity-eu-lab.html">QuantityEuLab</a></td><td style="vertical-align: top; text-align : var(--ig-left,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 : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck10.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_vjoin.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-quantity-it-lab-definitions.html#Quantity.value">value</a><a name="Quantity.value"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,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 : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a style="opacity: 0.5; opacity: 0.5" href="http://hl7.org/fhir/R4/datatypes.html#decimal">decimal</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">Valore della misurazione.</td></tr>
    <tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white"><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(tbl_bck10.png)" class="hierarchy"><img src="tbl_spacer.png" alt="." style="background-color: inherit" class="hierarchy"/><img src="tbl_vjoin.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-quantity-it-lab-definitions.html#Quantity.unit">unit</a><a name="Quantity.unit"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; 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 : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a style="opacity: 0.5; opacity: 0.5" href="http://hl7.org/fhir/R4/datatypes.html#string">string</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">Descrizione testuale dell'unità di misura.</td></tr>
    <tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: #F7F7F7"><td style="vertical-align: top; text-align : var(--ig-left,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-quantity-it-lab-definitions.html#Quantity.code">code</a><a name="Quantity.code"> </a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"/><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><span style="opacity: 0.5">1</span><span style="opacity: 0.5">..</span><span style="opacity: 0.5">1</span></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"><a style="opacity: 0.5; opacity: 0.5" href="http://hl7.org/fhir/R4/datatypes.html#code">code</a></td><td style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">Descrizione codificata dell'unità di misura secondo UCUM.<br class="binding"/><span style="font-weight:bold" title="null" class="binding">Binding: </span><a href="http://hl7.org/fhir/R4/valueset-ucum-units.html" title="http://hl7.org/fhir/ValueSet/ucum-units" class="binding">UCUMCodes</a><span title="null" class="binding"> (</span><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." class="binding">required</a><span title="null" class="binding">)</span></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, " alt="doco" style="background-color: inherit"/> Documentation for this format</a></td></tr></table></div>
      </text>
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm">
        <valueInteger value="1"/>
      </extension>
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
        <valueCode value="trial-use"/>
      </extension>
      <url
           value="http://hl7.it/fhir/lab-report/StructureDefinition/quantity-it-lab"/>
      <version value="0.2.0"/>
      <name value="QuantityLab"/>
      <title value="Quantity - Lab Report"/>
      <status value="active"/>
      <date value="2025-11-18T15:38:51+00:00"/>
      <publisher value="HL7 Italia"/>
      <contact>
        <name value="HL7 Italia"/>
        <telecom>
          <system value="url"/>
          <value value="https://hl7.it"/>
        </telecom>
      </contact>
      <contact>
        <name value="HL7 Italia"/>
        <telecom>
          <system value="url"/>
          <value value="https://hl7.it"/>
        </telecom>
      </contact>
      <description value="Descrizione del valore ottenuto da una misurazione."/>
      <jurisdiction>
        <coding>
          <system value="urn:iso:std:iso:3166"/>
          <code value="IT"/>
          <display value="Italy"/>
        </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.eu/fhir/laboratory/StructureDefinition/Quantity-eu-lab"/>
      <derivation value="constraint"/>
      <snapshot>
        <extension
                   url="http://hl7.org/fhir/tools/StructureDefinition/snapshot-base-version">
          <valueString value="0.1.0"/>
        </extension>
        <element id="Quantity">
          <path value="Quantity"/>
          <short value="A measured amount using UCUM"/>
          <definition
                      value="A measured amount (or an amount that can potentially be measured) and uncertainty of the measurement. Note that measured amounts include amounts that are not precisely quantified, including amounts involving arbitrary units and floating currencies.
    This profile imposes that the code system for units be UCUM."/>
          <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>
          <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.extension:uncertainty">
          <path value="Quantity.extension"/>
          <sliceName value="uncertainty"/>
          <short value="Standard Deviation (same units as the quantity)"/>
          <definition
                      value="The primary measure of variance/uncertainty of the value (the square root of the sum of the squares of the differences between all data points and the mean)."/>
          <comment
                   value="standardDeviation has the same units as the quantity. It is used to normalize the data for computing the distribution function. Applications that cannot deal with probability distributions can still get an idea about the confidence level by looking at standardDeviation."/>
          <min value="0"/>
          <max value="1"/>
          <base>
            <path value="Element.extension"/>
            <min value="0"/>
            <max value="*"/>
          </base>
          <type>
            <code value="Extension"/>
            <profile
                     value="http://hl7.org/fhir/StructureDefinition/iso21090-uncertainty"/>
          </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="PPD.standardDeviation"/>
          </mapping>
        </element>
        <element id="Quantity.extension:uncertaintyType">
          <path value="Quantity.extension"/>
          <sliceName value="uncertaintyType"/>
          <short value="Probability Distribution Type for uncertainty"/>
          <definition
                      value="A code specifying the type of probability distribution for the uncertainty."/>
          <comment
                   value="This is only meaningful if there is also an uncertainty extension. If there is an uncertainty extension with no type, this means  that the probability distribution type is unknown. In that case, the uncertainty has the meaning of an informal guess."/>
          <min value="0"/>
          <max value="1"/>
          <base>
            <path value="Element.extension"/>
            <min value="0"/>
            <max value="*"/>
          </base>
          <type>
            <code value="Extension"/>
            <profile
                     value="http://hl7.org/fhir/StructureDefinition/iso21090-uncertaintyType"/>
          </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="PPD.distributionType"/>
          </mapping>
        </element>
        <element id="Quantity.value">
          <path value="Quantity.value"/>
          <short value="Valore della misurazione."/>
          <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="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 &quot;&lt;&quot; , then the real value is &lt; stated value."/>
          <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="1"/>
          <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="Descrizione testuale dell'unità di misura."/>
          <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="UCUM system for units"/>
          <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="1"/>
          <max value="1"/>
          <base>
            <path value="Quantity.system"/>
            <min value="0"/>
            <max value="1"/>
          </base>
          <type>
            <code value="uri"/>
          </type>
          <fixedUri value="http://unitsofmeasure.org"/>
          <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>
          <mustSupport value="true"/>
          <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="Descrizione codificata dell'unità di misura secondo UCUM."/>
          <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="1"/>
          <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>
          <mustSupport value="true"/>
          <isModifier value="false"/>
          <isSummary value="true"/>
          <binding>
            <strength value="required"/>
            <valueSet value="http://hl7.org/fhir/ValueSet/ucum-units"/>
          </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.value">
          <path value="Quantity.value"/>
          <short value="Valore della misurazione."/>
        </element>
        <element id="Quantity.unit">
          <path value="Quantity.unit"/>
          <short value="Descrizione testuale dell'unità di misura."/>
        </element>
        <element id="Quantity.code">
          <path value="Quantity.code"/>
          <short
                 value="Descrizione codificata dell'unità di misura secondo UCUM."/>
          <binding>
            <strength value="required"/>
            <valueSet value="http://hl7.org/fhir/ValueSet/ucum-units"/>
          </binding>
        </element>
      </differential>
    </StructureDefinition>