<StructureDefinition xmlns="http://hl7.org/fhir">
  <id value="Duration" />
  <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;">
          <th style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">
            <a href="formats.html#table" title="The logical name of the element">Name</a>
          </th>
          <th style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">
            <a href="formats.html#table" title="Information about the use of the element">Flags</a>
          </th>
          <th style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">
            <a href="formats.html#table" title="Minimum and Maximum # of times the the element can appear in the instance">Card.</a>
          </th>
          <th style="width: 100px" class="hierarchy">
            <a href="formats.html#table" title="Reference to the type of the element">Type</a>
          </th>
          <th style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">
            <a href="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 src="help16.png" alt="doco" style="background-color: inherit" />
              </a>
            </span>
          </th>
        </tr>
        <tr style="border: 0px #F0F0F0 solid; padding:0px; vertical-align: top; background-color: white;">
          <td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px; white-space: nowrap; background-image: url(data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAyAAAAACCAYAAACg/LjIAAAAL0lEQVR42u3XsQ0AQAgCQHdl/xn8jxvYWB3JlTR0VJLa+OltBwAAYP6EEQAAgCsPVYVAgIJrA/sAAAAASUVORK5CYII=)" class="hierarchy">
            <img src="data: image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAAWCAYAAAABxvaqAAAACXBIWXMAAAsTAAALEwEAmpwYAAAAB3RJTUUH3wYeFzIs1vtcMQAAAB1pVFh0Q29tbWVudAAAAAAAQ3JlYXRlZCB3aXRoIEdJTVBkLmUHAAAAE0lEQVQI12P4//8/AxMDAwNdCABMPwMo2ctnoQAAAABJRU5ErkJggg==" alt="." style="background-color: inherit" class="hierarchy" />
            <img src="data: image/png;base64,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" alt="." style="background-color: white; background-color: inherit" title="Data Type" class="hierarchy" />
            <a href="datatypes-definitions.html#Duration" title="Duration : A length of time.">Duration</a>
          </td>
          <td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">
            <a style="padding-left: 3px; padding-right: 3px; color: black; null" href="elementdefinition-definitions.html#ElementDefinition.isSummary" title="This element is included in summaries">Σ</a>
            <a style="padding-left: 3px; padding-right: 3px; color: black; null" href="conformance-rules.html#constraints" title="This element has or is affected by some invariants">I</a>
            <a style="padding-left: 3px; padding-right: 3px; border: 1px grey solid; font-weight: bold; color: black; background-color: #e6ffe6" href="versions.html#std-process" title="Standards Status = Normative">N</a>
          </td>
          <td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy"></td>
          <td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">
            <a href="datatypes.html#Quantity">Quantity</a>
          </td>
          <td style="vertical-align: top; text-align : left; background-color: white; border: 0px #F0F0F0 solid; padding:0px 4px 0px 4px" class="hierarchy">A length of time<br /><a href="valueset-duration-units.html" title="Appropriate units for Duration.">Common UCUM Codes for Duration</a> (<a href="terminologies.html#extensible" title="To be conformant, the concept in this element SHALL be from the specified value set if any of the codes within the value set can apply to the concept being communicated.  If the value set does not cover the concept (based on human review), alternate codings (or, data type allowing, text) may be included instead.">Extensible</a> but limited to <a href="valueset-all-time-units.html">AllUCUMExpressionForTime</a>)<br /><span style="font-style: italic" title="drt-1">+ Rule: There SHALL be a code if there is a value and it SHALL be an expression of time.  If system is present, it SHALL be UCUM.</span><br />Elements defined in Ancestors: <a href="element.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="element.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 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.">extension</a>, <a href="datatypes.html#Quantity" title="The value of the measured amount. The value includes an implicit precision in the presentation of the value.">value</a>, <a href="datatypes.html#Quantity" title="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 href="datatypes.html#Quantity" title="A human-readable form of the unit.">unit</a>, <a href="datatypes.html#Quantity" title="The identification of the system that provides the coded form of the unit.">system</a>, <a href="datatypes.html#Quantity" title="A computer processable form of the unit in some unit representation system.">code</a></td>
        </tr>
        <tr>
          <td colspan="5" class="hierarchy">
            <br />
            <a href="formats.html#table" title="Legend for this format">
              <img src="help16.png" alt="doco" 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-normative-version">
    <valueCode value="4.0.0" />
  </extension>
  <url value="http://hl7.org/fhir/StructureDefinition/Duration" />
  <version value="4.0.1" />
  <name value="Duration" />
  <status value="active" />
  <date value="2019-11-01T09:29:23+11:00" />
  <publisher value="HL7 FHIR Standard" />
  <contact>
    <telecom>
      <system value="url" />
      <value value="http://hl7.org/fhir" />
    </telecom>
  </contact>
  <description value="Base StructureDefinition for Duration Type: A length of time." />
  <fhirVersion value="4.0.1" />
  <mapping>
    <identity value="rim" />
    <uri value="http://hl7.org/v3" />
    <name value="RIM Mapping" />
  </mapping>
  <mapping>
    <identity value="v2" />
    <uri value="http://hl7.org/v2" />
    <name value="HL7 v2 Mapping" />
  </mapping>
  <kind value="complex-type" />
  <abstract value="false" />
  <type value="Duration" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Quantity" />
  <derivation value="specialization" />
  <snapshot />
  <differential>
    <element id="Duration">
      <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
        <valueCode value="normative" />
      </extension>
      <extension url="http://hl7.org/fhir/StructureDefinition/structuredefinition-normative-version">
        <valueCode value="4.0.0" />
      </extension>
      <path value="Duration" />
      <short value="A length of time" />
      <definition value="A length of time." />
      <min value="0" />
      <max value="*" />
      <constraint>
        <key value="drt-1" />
        <severity value="error" />
        <human value="There SHALL be a code if there is a value and it SHALL be an expression of time.  If system is present, it SHALL be UCUM." />
        <expression value="code.exists() implies ((system = %ucum) and value.exists())" />
        <xpath value="(f:code or not(f:value)) and (not(exists(f:system)) or f:system/@value='http://unitsofmeasure.org')" />
      </constraint>
      <binding>
        <extension url="http://hl7.org/fhir/StructureDefinition/elementdefinition-maxValueSet">
          <valueCanonical value="http://hl7.org/fhir/ValueSet/all-time-units" />
        </extension>
        <extension url="http://hl7.org/fhir/StructureDefinition/elementdefinition-bindingName">
          <valueString value="DurationUnits" />
        </extension>
        <strength value="extensible" />
        <description value="Appropriate units for Duration." />
        <valueSet value="http://hl7.org/fhir/ValueSet/duration-units" />
      </binding>
      <mapping>
        <identity value="rim" />
        <map value="PQ, IVL&lt;PQ&gt; depending on the values" />
      </mapping>
    </element>
  </differential>
</StructureDefinition>