Release 5 FHIR CI-Build

This page is part of the Continuous Integration Build of FHIR Specification (v5.0.0: R5 - STU ). This is the current published version in it's permanent home (it will always (will be available incorrect/inconsistent at this URL). For a full list of available versions, see times).
See the Directory of published versions . Page versions: R5 R4B R4 R3 R2

Example StructureDefinition/Ratio (XML)

Maturity Level : N/A
Responsible Owner: Modeling and Methodology Work Group Standards Status : Informative

Raw XML ( canonical form + also see XML Format Specification )

StructureDefinition for Ratio 

<?xml version="1.0" encoding="UTF-8"?>

<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="Ratio"/> 
  <text> 
    <status value="generated"/> 
    <div xmlns="http://www.w3.org/1999/xhtml">
      <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">
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px

          <th class="hierarchy" 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">

            <a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="The logical name of the element">Name</a> 
          </th> 
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px

          <th class="hierarchy" 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">

            <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> 
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px
            

          <th class="hierarchy" 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">
            <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 class="hierarchy" 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">

            <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> 
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px

          <th class="hierarchy" 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">

            <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 alt="doco" src="data:(snipped in html view)" style="background-color: inherit"/> 
              </a> 
            </span> 
          </th> 
        </tr> 
        <tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color:
         white">
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;bas
          e64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAJUlEQVR4Xu3IIQEAAAgDsHd9/w4EQIOamFnaBgAA4M
          MKAACAKwNp30CqZFfFmwAAAABJRU5ErkJggg==)

          <td class="hierarchy" 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(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAJUlEQVR4Xu3IIQEAAAg
          DsHd9/w4EQIOamFnaBgAA4MMKAACAKwNp30CqZFfFmwAAAABJRU5ErkJggg==)">

            <img alt="." class="hierarchy" src="data:(snipped in html view)" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:(snipped in html view)" style="background-color: white; background-color: inherit" title="Element"/>  
            <a href="datatypes-definitions.html#Ratio" title="Ratio : A relationship of two Quantity values - expressed as a numerator and a
             denominator.">Ratio</a> 
          </td> 
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px
            

          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: white;
           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">
            <a href="elementdefinition-definitions.html#ElementDefinition.isSummary" style="padding-left: 3px; padding-right: 3px; color: black; null; padding-left: 3px; padding-right:

             3px; color: black; null" title="This element is included in summaries">Σ</a> 

            <a href="versions.html#std-process" style="padding-left: 3px; padding-right: 3px; border: 1px grey solid; font-weight: bold;
             color: black; background-color: #e6ffe6

             color: black; background-color: #e6ffe6; padding-left: 3px; padding-right: 3px;
             border: 1px grey solid; font-weight: bold; color: black; background-color: #e6ffe6" title="Standards Status = Normative">N</a> 

          </td> 
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px

          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: white;
           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px"/> 
          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: white;

           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">

            <a href="types.html#Element">Element</a> 
          </td> 
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4pxA ratio of two Quantity values - a numerator and a denominator

          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: white;
           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">A ratio of two Quantity values - a numerator and a denominator

            <br/>  
            <span style="font-style: italic" title="rat-1">+ Rule: Numerator and denominator SHALL both be present, or both are absent. If
               both are absent, there SHALL be some extension present</span> 
            <br/>  
            <br/>  Elements defined in Ancestors: 
            <a href="types.html#Element" title="Unique id for the element within a resource (for internal references). This may
             be any string value that does not contain spaces.">id</a> , 
            <a href="types.html#Element" title="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 managable, 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.">extension</a> 
          </td> 
        </tr> 
        <tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color:
         #F7F7F7">
          vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image:

          <td class="hierarchy" 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(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAALUlEQVR4Xu3IoREAIAw
          EwfT6/ddA0GBAxO3NrLlKUj9263wAAAAvrgEAADClAVWFQIBRHMicAAAAAElFTkSuQmCC)">
            <img alt="." class="hierarchy" src="data:(snipped in html view)" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:(snipped in html view)" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:(snipped in html view)" style="background-color: #F7F7F7; background-color: inherit" title="Data Type"/>  
            <a href="datatypes-definitions.html#Ratio.numerator" title="Ratio.numerator : The value of the numerator.">numerator</a> 
          </td> 
          vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4px
            

          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7;
           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">
            <a href="elementdefinition-definitions.html#ElementDefinition.isSummary" style="padding-left: 3px; padding-right: 3px; color: black; null; padding-left: 3px; padding-right:

             3px; color: black; null" title="This element is included in summaries">Σ</a> 

            <a href="conformance-rules.html#constraints" style="padding-left: 3px; padding-right: 3px; border: 1px maroon solid; font-weight: bold;
             color: #301212; background-color: #fdf4f4;

             color: #301212; background-color: #fdf4f4;; padding-left: 3px; padding-right: 3px;
             border: 1px maroon solid; font-weight: bold; color: #301212; background-color:
             #fdf4f4;" title="This element has or is affected by some invariants">C</a> 

          </td> 
          vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4px
          vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4px

          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7;
           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">0..1</td> 
          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7;

           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">

            <a href="datatypes.html#Quantity">Quantity</a> 
          </td> 
          vertical-align: top; text-align : left; background-color: #F7F7F7; border: 0px
           #F0F0F0 solid; padding:0px 4px 0px 4pxNumerator value

          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: #F7F7F7;
           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">Numerator value

            <br/>  
          </td> 
        </tr> 
        <tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color:
         white">
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data:image/png;bas
          e64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAJUlEQVR4Xu3IIQEAAAgDsHd9/w4EQIOamFnaBgAA4M
          MKAACAKwNp30CqZFfFmwAAAABJRU5ErkJggg==)

          <td class="hierarchy" 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(data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAJUlEQVR4Xu3IIQEAAAg
          DsHd9/w4EQIOamFnaBgAA4MMKAACAKwNp30CqZFfFmwAAAABJRU5ErkJggg==)">

            <img alt="." class="hierarchy" src="data:(snipped in html view)" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:(snipped in html view)" style="background-color: inherit"/> 
            <img alt="." class="hierarchy" src="data:(snipped in html view)" style="background-color: white; background-color: inherit" title="Data Type"/>  
            <a href="datatypes-definitions.html#Ratio.denominator" title="Ratio.denominator : The value of the denominator.">denominator</a> 
          </td> 
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px
            

          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: white;
           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">
            <a href="elementdefinition-definitions.html#ElementDefinition.isSummary" style="padding-left: 3px; padding-right: 3px; color: black; null; padding-left: 3px; padding-right:

             3px; color: black; null" title="This element is included in summaries">Σ</a> 

            <a href="conformance-rules.html#constraints" style="padding-left: 3px; padding-right: 3px; border: 1px maroon solid; font-weight: bold;
             color: #301212; background-color: #fdf4f4;

             color: #301212; background-color: #fdf4f4;; padding-left: 3px; padding-right: 3px;
             border: 1px maroon solid; font-weight: bold; color: #301212; background-color:
             #fdf4f4;" title="This element has or is affected by some invariants">C</a> 

          </td> 
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4px

          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: white;
           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">0..1</td> 
          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: white;

           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">

            <a href="datatypes.html#SimpleQuantity">SimpleQuantity</a> 
          </td> 
          vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0
           solid; padding:0px 4px 0px 4pxDenominator value

          <td class="hierarchy" style="vertical-align: top; text-align : var(--ig-left,left); background-color: white;
           border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px">Denominator value

            <br/>  
          </td> 
        </tr> 
        <tr> 
          <td class="hierarchy" colspan="5">
            <br/>  
            <a href="https://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#table-views" title="Legend for this format">
              <img alt="doco" src="data:(snipped in html view)" style="background-color: inherit"/>  Documentation for this format
            </a> 
          </td> 
        </tr> 
      </table> 
    </div> 
  </text> 
  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
    <valueCode value="normative"/> 
  </extension> 
  
    

  <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-wg">
    <valueCode value="fhir"/> 
  </extension> 
  <url value="http://hl7.org/fhir/StructureDefinition/Ratio"/> 
  

  <version value="6.0.0-ballot3"/> 
  <name value="Ratio"/> 
  <status value="active"/> 
  <experimental value="false"/> 
  
  

  <date value="2025-11-08T03:13:31+00:00"/> 
  <publisher value="HL7 International / FHIR Infrastructure"/> 
  <contact> 
    <telecom> 
      <system value="url"/> 
      <value value="http://hl7.org/fhir"/> 
    </telecom> 
  </contact> 
  <contact> 
    <telecom> 
      <system value="url"/> 
      <value value="http://www.hl7.org/Special/committees/fiwg"/> 
    </telecom> 
  </contact> 
  <description value="Ratio Type: A relationship of two Quantity values - expressed as a numerator and
   a denominator."/> 
  <jurisdiction> 
    <coding> 
      <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/> 
      <code value="001"/> 
      <display value="World"/> 
    </coding> 
  </jurisdiction> 
  <purpose value="Need to able to capture ratios for some measurements (titers) and some rates (costs)."/> 
  

  <fhirVersion value="6.0.0-ballot3"/> 
  <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="Ratio"/> 
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/DataType"/> 
  <derivation value="specialization"/> 
  <snapshot> 
    <element id="Ratio">
      
        
      
      
        
      

      <path value="Ratio"/> 
      <short value="A ratio of two Quantity values - a numerator and a denominator"/> 
      <definition value="A relationship of two Quantity values - expressed as a numerator and a denominator."/> 
      <comment value="The Ratio datatype should only be used to express a relationship of two numbers
       if the relationship cannot be suitably expressed using a Quantity and a common
       unit.  Where the denominator value is known to be fixed to &quot;1&quot;, Quantity
       should be used instead of Ratio."/> 
      <min value="0"/> 
      <max value="*"/> 
      <base> 
        <path value="Ratio"/> 
        <min value="0"/> 
        <max value="*"/> 
      </base> 
      <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())"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/> 
      </constraint> 
      <constraint> 
        <key value="rat-1"/> 
        <severity value="error"/> 
        <human value="Numerator and denominator SHALL both be present, or both are absent. If both are
         absent, there SHALL be some extension present"/> 
        <expression value="(numerator.exists() and denominator.exists()) or (numerator.empty() and denominator.empty()
         and extension.exists())"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Ratio"/> 
      </constraint> 
      <isModifier value="false"/> 
      <mapping> 
        <identity value="rim"/> 
        <map value="n/a,RTO"/> 
      </mapping> 
      <mapping> 
        <identity value="v2"/> 
        <map value="N/A"/> 
      </mapping> 
    </element> 
    <element id="Ratio.id">
      <path value="Ratio.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> 
      <!--  Note: special primitive values have a FHIRPath system type. e.g. this is compiler
       magic (j)  -->
      <type> 
        <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type">
          

          <valueUrl value="string"/> 
        </extension> 
        <code value="http://hl7.org/fhirpath/System.String"/> 
      </type> 
      <condition value="ele-1"/> 
      <isModifier value="false"/> 
      <isSummary value="false"/> 
      <mapping> 
        <identity value="rim"/> 
        <map value="n/a"/> 
      </mapping> 
    </element> 
    <element id="Ratio.extension">
      <path value="Ratio.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 managable, 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())"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/> 
      </constraint> 
      
        
        
        
        
        
      

      <isModifier value="false"/> 
      <isSummary value="false"/> 
      <mapping> 
        <identity value="rim"/> 
        <map value="n/a"/> 
      </mapping> 
    </element> 
    <element id="Ratio.numerator">
      <path value="Ratio.numerator"/> 
      <short value="Numerator value"/> 
      <definition value="The value of the numerator."/> 
      <min value="0"/> 
      <max value="1"/> 
      <base> 
        <path value="Ratio.numerator"/> 
        <min value="0"/> 
        <max value="1"/> 
      </base> 
      <type> 
        <code value="Quantity"/> 
      </type> 
      <condition value="rat-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())"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/> 
      </constraint> 
      <isModifier value="false"/> 
      <isSummary value="true"/> 
      <mapping> 
        <identity value="rim"/> 
        <map value=".numerator"/> 
      </mapping> 
    </element> 
    <element id="Ratio.denominator">
      <path value="Ratio.denominator"/> 
      <short value="Denominator value"/> 
      <definition value="The value of the denominator."/> 
      <min value="0"/> 
      <max value="1"/> 
      <base> 
        <path value="Ratio.denominator"/> 
        <min value="0"/> 
        <max value="1"/> 
      </base> 
      <type> 
        <code value="Quantity"/> 
        <profile value="http://hl7.org/fhir/StructureDefinition/SimpleQuantity"/> 
      </type> 
      <condition value="rat-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())"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Element"/> 
      </constraint> 
      <isModifier value="false"/> 
      <isSummary value="true"/> 
      <mapping> 
        <identity value="rim"/> 
        <map value=".denominator"/> 
      </mapping> 
    </element> 
  </snapshot> 
  <differential> 
    <element id="Ratio">
      
        
      
      
        
      

      <path value="Ratio"/> 
      <short value="A ratio of two Quantity values - a numerator and a denominator"/> 
      <definition value="A relationship of two Quantity values - expressed as a numerator and a denominator."/> 
      <comment value="The Ratio datatype should only be used to express a relationship of two numbers
       if the relationship cannot be suitably expressed using a Quantity and a common
       unit.  Where the denominator value is known to be fixed to &quot;1&quot;, Quantity
       should be used instead of Ratio."/> 
      <min value="0"/> 
      <max value="*"/> 
      <constraint> 
        <key value="rat-1"/> 
        <severity value="error"/> 
        <human value="Numerator and denominator SHALL both be present, or both are absent. If both are
         absent, there SHALL be some extension present"/> 
        <expression value="(numerator.exists() and denominator.exists()) or (numerator.empty() and denominator.empty()
         and extension.exists())"/> 
        <source value="http://hl7.org/fhir/StructureDefinition/Ratio"/> 
      </constraint> 
      <mapping> 
        <identity value="v2"/> 
        <map value="N/A"/> 
      </mapping> 
      <mapping> 
        <identity value="rim"/> 
        <map value="RTO"/> 
      </mapping> 
    </element> 
    <element id="Ratio.numerator">
      <path value="Ratio.numerator"/> 
      <short value="Numerator value"/> 
      <definition value="The value of the numerator."/> 
      <min value="0"/> 
      <max value="1"/> 
      <type> 
        <code value="Quantity"/> 
      </type> 
      <condition value="rat-1"/> 
      <isSummary value="true"/> 
      <mapping> 
        <identity value="rim"/> 
        <map value=".numerator"/> 
      </mapping> 
    </element> 
    <element id="Ratio.denominator">
      <path value="Ratio.denominator"/> 
      <short value="Denominator value"/> 
      <definition value="The value of the denominator."/> 
      <min value="0"/> 
      <max value="1"/> 
      <type> 
        <code value="Quantity"/> 
        <profile value="http://hl7.org/fhir/StructureDefinition/SimpleQuantity"/> 
      </type> 
      <condition value="rat-1"/> 
      <isSummary value="true"/> 
      <mapping> 
        <identity value="rim"/> 
        <map value=".denominator"/> 
      </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.