STU 3 Candidate

This page is part of the FHIR Specification (v1.4.0: STU 3 Ballot 3). The current version which supercedes this version is 5.0.0. For a full list of available versions, see the Directory of published versions . Page versions: R5 R4B R4 R3 R2

Quantity.profile.xml

Raw XML (canonical form)

StructureDefinition for Quantity

<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="Quantity"/>
  <text>
    <status value="generated"/>
    <div xmlns="http://www.w3.org/1999/xhtml">
      <table border="0" cellpadding="0" cellspacing="0" style="border: 0px; 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 class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="formats.html#table" title="The logical name of the element">Name</a>
          </th>
          <th class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="formats.html#table" title="Information about the use of the element">Flags</a>
          </th>
          <th class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="formats.html#table" title="Minimum and Maximum # of times the the element can appear in the instance">Card.</a>
          </th>
          <th class="hierarchy" style="width: 100px">
            <a href="formats.html#table" title="Reference to the type of the element">Type</a>
          </th>
          <th class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="formats.html#table" title="Additional information about the element">Description &amp; Constraints</a>
            <span style="float: right">
              <a href="formats.html#table" title="Legend for this format">
                <img alt="doco" src="help16.png" style="background-color: inherit"/>
              </a>
            </span>
          </th>
        </tr>
        <tr style="border: 0px; padding:0px; vertical-align: top; background-color: white;">
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px;
           white-space: nowrap; background-image: url(data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCA
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          CYII=)">
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
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            NdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" style="background-color: inherit"/>
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            /npofbjquvNefHVduuyN+uuMu3Oafbgjfnqvf/3zv/3xevPi+vRjP/20/bmsP///////yH5BAEAAB8ALAAAAAAQABAAAAV24CeOZG
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            FEhIdcAYJdYASFRUQhQkLCwkOFwcdEBAXhVabE52ecDahKy0oIQA7" style="background-color: white; background-color: inherit" title="Element"/> 
            <a href="datatypes-definitions.html#Quantity" title="Quantity : 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.">Quantity</a>
            <a name="Quantity"> </a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <span title="This element is included in summaries">Σ </span>
            <span title="This element has or is affected by some invariants">I</span>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px"/>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="element.html">Element</a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">A measured or measurable amount
            <br/>
            <span style="font-style: italic" title="qty-3">If a code for the unit is present, the system SHALL also be present</span>
          </td>
        </tr>

        <tr style="border: 0px; padding:0px; vertical-align: top; background-color: white;">
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px;
           white-space: nowrap; background-image: url(data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCA
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          CYII=)">
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAw
            NdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" style="background-color: inherit"/>
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzI3XJ6V3QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+2RsQ0AIAzDav
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            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIW
            XMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3gYBFzI0BrFQCwAAAERJREFUOMtj/P//PwMlgImBQjDwBrCcOnWKokBgYWBgYDCU+06W5i
            8MUggvnH/EOVJjAW4AuQHJ+O75LYqikXE0LzAAALePEntTkEoSAAAAAElFTkSuQmCC" style="background-color: white; background-color: inherit" title="Primitive Data Type"/> 
            <a href="datatypes-definitions.html#Quantity.value" title="Quantity.value : The value of the measured amount. The value includes an implicit precision
             in the presentation of the value.">value</a>
            <a name="Quantity.value"> </a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <span title="This element is included in summaries">Σ</span>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">0..1</td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="datatypes.html#decimal">decimal</a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">Numerical value (with implicit precision)</td>
        </tr>

        <tr style="border: 0px; padding:0px; vertical-align: top; background-color: white;">
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px;
           white-space: nowrap; background-image: url(data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCA
          YAAACg/LjIAAAAL0lEQVR42u3XsQ0AQAgCQHdl/xn8jxvYWB3JlTR0VJLa+OltBwAAYP6EEQAAgCsPVYVAgIJrA/sAAAAASUVORK5
          CYII=)">
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAw
            NdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" style="background-color: inherit"/>
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzI3XJ6V3QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+2RsQ0AIAzDav
            7/2VzQwoCY4iWbZSmo1QGoUgNMghvWaIejPQW/CrrNCylIwcOCDYfLNRcNer4SAAAAAElFTkSuQmCC" style="background-color: inherit"/>
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIW
            XMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3gYBFzI0BrFQCwAAAERJREFUOMtj/P//PwMlgImBQjDwBrCcOnWKokBgYWBgYDCU+06W5i
            8MUggvnH/EOVJjAW4AuQHJ+O75LYqikXE0LzAAALePEntTkEoSAAAAAElFTkSuQmCC" style="background-color: white; background-color: inherit" title="Primitive Data Type"/> 
            <a href="datatypes-definitions.html#Quantity.comparator" title="Quantity.comparator : 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.">comparator</a>
            <a name="Quantity.comparator"> </a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <span title="This element is a modifier element">?! </span>
            <span title="This element is included in summaries">Σ</span>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">0..1</td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="datatypes.html#code">code</a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">&lt; | &lt;= | &gt;= | &gt; - how to understand the value
            <br/>
            <a href="valueset-quantity-comparator.html" title="How the Quantity should be understood and represented.">QuantityComparator</a> (
            <a href="terminologies.html#required" title="To be conformant, instances of this element SHALL include a code from the specified value
             set.">Required</a>)
          </td>
        </tr>

        <tr style="border: 0px; padding:0px; vertical-align: top; background-color: white;">
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px;
           white-space: nowrap; background-image: url(data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCA
          YAAACg/LjIAAAAL0lEQVR42u3XsQ0AQAgCQHdl/xn8jxvYWB3JlTR0VJLa+OltBwAAYP6EEQAAgCsPVYVAgIJrA/sAAAAASUVORK5
          CYII=)">
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAw
            NdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" style="background-color: inherit"/>
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzI3XJ6V3QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+2RsQ0AIAzDav
            7/2VzQwoCY4iWbZSmo1QGoUgNMghvWaIejPQW/CrrNCylIwcOCDYfLNRcNer4SAAAAAElFTkSuQmCC" style="background-color: inherit"/>
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIW
            XMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3gYBFzI0BrFQCwAAAERJREFUOMtj/P//PwMlgImBQjDwBrCcOnWKokBgYWBgYDCU+06W5i
            8MUggvnH/EOVJjAW4AuQHJ+O75LYqikXE0LzAAALePEntTkEoSAAAAAElFTkSuQmCC" style="background-color: white; background-color: inherit" title="Primitive Data Type"/> 
            <a href="datatypes-definitions.html#Quantity.unit" title="Quantity.unit : A human-readable form of the unit.">unit</a>
            <a name="Quantity.unit"> </a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <span title="This element is included in summaries">Σ</span>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">0..1</td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="datatypes.html#string">string</a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">Unit representation</td>
        </tr>

        <tr style="border: 0px; padding:0px; vertical-align: top; background-color: white;">
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px;
           white-space: nowrap; background-image: url(data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCA
          YAAACg/LjIAAAAL0lEQVR42u3XsQ0AQAgCQHdl/xn8jxvYWB3JlTR0VJLa+OltBwAAYP6EEQAAgCsPVYVAgIJrA/sAAAAASUVORK5
          CYII=)">
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAw
            NdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" style="background-color: inherit"/>
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzI3XJ6V3QAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+2RsQ0AIAzDav
            7/2VzQwoCY4iWbZSmo1QGoUgNMghvWaIejPQW/CrrNCylIwcOCDYfLNRcNer4SAAAAAElFTkSuQmCC" style="background-color: inherit"/>
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIW
            XMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3gYBFzI0BrFQCwAAAERJREFUOMtj/P//PwMlgImBQjDwBrCcOnWKokBgYWBgYDCU+06W5i
            8MUggvnH/EOVJjAW4AuQHJ+O75LYqikXE0LzAAALePEntTkEoSAAAAAElFTkSuQmCC" style="background-color: white; background-color: inherit" title="Primitive Data Type"/> 
            <a href="datatypes-definitions.html#Quantity.system" title="Quantity.system : The identification of the system that provides the coded form of the
             unit.">system</a>
            <a name="Quantity.system"> </a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <span title="This element is included in summaries">Σ </span>
            <span title="This element has or is affected by some invariants">I</span>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">0..1</td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="datatypes.html#uri">uri</a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">System that defines coded unit form</td>
        </tr>

        <tr style="border: 0px; padding:0px; vertical-align: top; background-color: white;">
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px;
           white-space: nowrap; background-image: url(data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCA
          YAAACg/LjIAAAAI0lEQVR42u3QIQEAAAACIL/6/4MvTAQOkLYBAAB4kAAAANwMad9AqkRjgNAAAAAASUVORK5CYII=)">
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAw
            NdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" style="background-color: inherit"/>
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAWCAYAAADJqhx8AAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB
            3RJTUUH3wYeFzME+lXFigAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAANklEQVQ4y+3OsRUAIAjEUO
            L+O8cJABttJM11/x1qZAGqRBEVcNIqdWj1efDqQbb3HwwwwEfABmQUHSPM9dtDAAAAAElFTkSuQmCC" style="background-color: inherit"/>
            <img alt="." class="hierarchy" src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAABmJLR0QA/wD/AP+gvaeTAAAACXBIW
            XMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3gYBFzI0BrFQCwAAAERJREFUOMtj/P//PwMlgImBQjDwBrCcOnWKokBgYWBgYDCU+06W5i
            8MUggvnH/EOVJjAW4AuQHJ+O75LYqikXE0LzAAALePEntTkEoSAAAAAElFTkSuQmCC" style="background-color: white; background-color: inherit" title="Primitive Data Type"/> 
            <a href="datatypes-definitions.html#Quantity.code" title="Quantity.code : A computer processable form of the unit in some unit representation system.">code</a>
            <a name="Quantity.code"> </a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <span title="This element is included in summaries">Σ</span>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">0..1</td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">
            <a href="datatypes.html#code">code</a>
          </td>
          <td class="hierarchy" style="vertical-align: top; text-align : left; background-color: white; padding:0px 4px 0px 4px">Coded form of the unit</td>
        </tr>

        <tr>
          <td class="hierarchy" colspan="5">
            <br/>
            <a href="formats.html#table" title="Legend for this format">
              <img alt="doco" src="help16.png" style="background-color: inherit"/> Documentation for this format
            </a>
          </td>
        </tr>
      </table>
    </div>
  </text>
  <url value="http://hl7.org/fhir/StructureDefinition/Quantity"/>
  <name value="Quantity"/>
  <status value="draft"/>
  <publisher value="HL7 FHIR Standard"/>
  <contact>
    <telecom>
      <system value="other"/>
      <value value="http://hl7.org/fhir"/>
    </telecom>
  </contact>
  <date value="2016-03-31T08:01:25+11:00"/>
  <description value="Base StructureDefinition for Quantity Type"/>
  <requirements value="Need to able to capture all sorts of measured values, even if the measured value are not
   precisely quantified. Values include exact measures such as 3.51g, customary units such
   as 3 tablets, and currencies such as $100.32USD."/>
  <fhirVersion value="1.4.0"/>
  <mapping>
    <identity value="v2"/>
    <uri value="http://hl7.org/v2"/>
    <name value="HL7 v2"/>
  </mapping>
  <mapping>
    <identity value="rim"/>
    <uri value="http://hl7.org/v3"/>
    <name value="RIM"/>
  </mapping>
  <kind value="datatype"/>
  <abstract value="false"/>
  <baseType value="Element"/>
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Element"/>
  <derivation value="specialization"/>
  <snapshot>
    <element>
      <path value="Quantity"/>
      <short value="A measured or measurable amount"/>
      <definition value="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."/>
      <comments 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="*"/>
      <type>
        <code value="Element"/>
      </type>
      <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"/>
        <xpath value="not(exists(f:code)) or exists(f:system)"/>
      </constraint>
      <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>
      <path value="Quantity.id"/>
      <representation value="xmlAttr"/>
      <short value="xml:id (or equivalent in JSON)"/>
      <definition value="unique id for the element within a resource (for internal references)."/>
      <min value="0"/>
      <max value="1"/>
      <base>
        <path value="Element.id"/>
        <min value="0"/>
        <max value="*"/>
      </base>
      <type>
        <code value="id"/>
      </type>
      <mapping>
        <identity value="rim"/>
        <map value="n/a"/>
      </mapping>
    </element>
    <element>
      <path value="Quantity.extension"/>
      <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. In order 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 is allowed to define an extension, there is a set of requirements that SHALL
       be met as part of the definition of the extension."/>
      <comments 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>
      <mapping>
        <identity value="rim"/>
        <map value="n/a"/>
      </mapping>
    </element>
    <element>
      <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."/>
      <comments 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"/>
      <type>
        <code value="decimal"/>
      </type>
      <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>
      <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."/>
      <comments 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."/>
      <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"/>
      <type>
        <code value="code"/>
      </type>
      <meaningWhenMissing value="If there is no comparator, then there is no modification of the value"/>
      <isModifier value="true"/>
      <isSummary value="true"/>
      <binding>
        <strength value="required"/>
        <description value="How the Quantity should be understood and represented."/>
        <valueSetReference>
          <reference value="http://hl7.org/fhir/ValueSet/quantity-comparator"/>
        </valueSetReference>
      </binding>
      <mapping>
        <identity value="v2"/>
        <map value="SN.1  / CQ.1"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="IVL properties"/>
      </mapping>
    </element>
    <element>
      <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"/>
      <type>
        <code value="string"/>
      </type>
      <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>
      <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"/>
      <type>
        <code value="uri"/>
      </type>
      <condition value="qty-3"/>
      <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>
      <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."/>
      <comments 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"/>
      <type>
        <code value="code"/>
      </type>
      <isSummary value="true"/>
      <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>
      <path value="Quantity"/>
      <short value="A measured or measurable amount"/>
      <definition value="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."/>
      <comments 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="*"/>
      <type>
        <code value="Element"/>
      </type>
      <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"/>
        <xpath value="not(exists(f:code)) or exists(f:system)"/>
      </constraint>
      <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>
      <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."/>
      <comments 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"/>
      <type>
        <code value="decimal"/>
      </type>
      <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>
      <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."/>
      <comments 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."/>
      <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"/>
      <type>
        <code value="code"/>
      </type>
      <meaningWhenMissing value="If there is no comparator, then there is no modification of the value"/>
      <isModifier value="true"/>
      <isSummary value="true"/>
      <binding>
        <strength value="required"/>
        <description value="How the Quantity should be understood and represented."/>
        <valueSetReference>
          <reference value="http://hl7.org/fhir/ValueSet/quantity-comparator"/>
        </valueSetReference>
      </binding>
      <mapping>
        <identity value="v2"/>
        <map value="SN.1  / CQ.1"/>
      </mapping>
      <mapping>
        <identity value="rim"/>
        <map value="IVL properties"/>
      </mapping>
    </element>
    <element>
      <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"/>
      <type>
        <code value="string"/>
      </type>
      <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>
      <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"/>
      <type>
        <code value="uri"/>
      </type>
      <condition value="qty-3"/>
      <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>
      <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."/>
      <comments 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"/>
      <type>
        <code value="code"/>
      </type>
      <isSummary value="true"/>
      <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>
  </differential>
</StructureDefinition>

Usage note: every effort has been made to ensure that the examples are correct and useful, but they are not a normative part of the specification.