Quality Measure Implementation Guide
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Quality Measure Implementation Guide, published by HL7 International / Clinical Quality Information. This guide is not an authorized publication; it is the continuous build for version 1.0.0 built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/fhir-cqm/ and changes regularly. See the Directory of published versions

: ISO-8601-Derived Periods Codes - XML Representation

Page standards status: Trial-use Maturity Level: 4

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<CodeSystem xmlns="http://hl7.org/fhir">
  <id value="iso-8601-derived-periods"/>
  <text>
    <status value="generated"/>
    <div xmlns="http://www.w3.org/1999/xhtml"><p class="res-header-id"><b>Generated Narrative: CodeSystem iso-8601-derived-periods</b></p><a name="iso-8601-derived-periods"> </a><a name="hciso-8601-derived-periods"> </a><p>This case-sensitive code system <code>http://terminology.hl7.org/CodeSystem/iso-8601-derived-periods</code> defines codes, but no codes are represented here</p></div>
  </text>
  <extension
             url="http://hl7.org/fhir/StructureDefinition/structuredefinition-wg">
    <valueCode value="cqi"/>
  </extension>
  <extension
             url="http://hl7.org/fhir/StructureDefinition/structuredefinition-fmm">
    <valueInteger value="4">
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom">
        <valueCanonical
                        value="http://hl7.org/fhir/uv/cqm/ImplementationGuide/hl7.fhir.uv.cqm"/>
      </extension>
    </valueInteger>
  </extension>
  <extension
             url="http://hl7.org/fhir/StructureDefinition/structuredefinition-standards-status">
    <valueCode value="trial-use">
      <extension
                 url="http://hl7.org/fhir/StructureDefinition/structuredefinition-conformance-derivedFrom">
        <valueCanonical
                        value="http://hl7.org/fhir/uv/cqm/ImplementationGuide/hl7.fhir.uv.cqm"/>
      </extension>
    </valueCode>
  </extension>
  <url
       value="http://terminology.hl7.org/CodeSystem/iso-8601-derived-periods"/>
  <identifier>
    <system value="urn:ietf:rfc:3986"/>
    <value value="urn:oid:2.16.840.1.113883.4.642.40.61.16.2"/>
  </identifier>
  <version value="1.0.0"/>
  <name value="ISO8601DerivedPeriodsCodes"/>
  <title value="ISO-8601-Derived Periods Codes"/>
  <status value="active"/>
  <experimental value="false"/>
  <date value="2025-06-27"/>
  <publisher value="HL7 International / Clinical Quality Information"/>
  <contact>
    <telecom>
      <system value="url"/>
      <value value="http://www.hl7.org/Special/committees/cqi"/>
    </telecom>
  </contact>
  <description
               value="Defines codes for the representation of age ranges that are unambiguous, human readable and machine-readable as a compositional grammar (i.e. the code system defines rules for constructing codes, rather than explicitly enumerating the possible codes). Age ranges are expressed through two simple durations as defined in the [ISO 8601](https://www.iso.org/iso-8601-date-and-time-format.html) specification.

Codes in the code system are defined according to the grammar:

An age range is defined as two durations: `[duration1]--[duration2]`, where `duration1` specifies the lower inclusive bound of the age range (everyone who is this age and above) and `duration2` specifies the upper exclusive bound of the age range.

For example, the age range &quot;1-9 years&quot; means everyone who is at least one year old and less than 10 years old represented as `P1Y--P10Y`. The age range &quot;10-14 years&quot; means everyone who is at least 10 years old and less than 15 years old and is represented as `P10Y--P15Y`.

Durations define the amount of time between two time points. These durations are represented in the form `P[n]Y[n]M[n]DT[n]H[n]M[n]S` or `P[n]W`. The `[n]` is replaced by the value for each of the time elements that follow the `[n]` and the letters have the meaning:

* `P` is the duration designator (for period) placed at the start of the duration representation.
	* `Y` is the year designator that follows the value for the number of years.
	* `M` is the month designator that follows the value for the number of months.
	* `W` is the week designator that follows the value for the number of weeks.
	* `D` is the day designator that follows the value for the number of days.
* `T` is the time designator that precedes the time components of the representation.
	* `H` is the hour designator that follows the value for the number of hours.
	* `M` is the minute designator that follows the value for the number of minutes.
	* `S` is the second designator that follows the value for the number of seconds. (Note that seconds can be a decimal in this format to allow for milliseconds)

For example, `P3Y6M4DT12H30M5S` represents a duration of _three years, six months, four days, twelve hours, thirty minutes, and five seconds_.

Date and time elements including their designator may be omitted if their value is zero, and lower-order elements may also be omitted for reduced precision. For example, `P23DT23H` and `P4Y` are both acceptable duration representations. However, at least one element must be present, thus `P` is not a valid representation for a duration of _0 seconds_. `PT0S` or `P0D`, however, are both valid and represent the same duration.

Note that the designator `M` is used for both months and minutes, but this is not ambiguous because the minutes designator must be preceded by the time designator `T`. For example `P1M` is _one month_, while `PT1M` is _one minute_.

Content for this code system is adapted from the definition in the IHE-ADX profile: https://www.ihe.net/uploadedFiles/Documents/QRPH/IHE_QRPH_Suppl_ADX.pdf (Appendix 8K Representation of Age Groups in ADX). In addition, the code system definition is adapted from similar content published as part of the SANER implementation guide. See [Age Range Coding System](https://hl7.org/fhir/uv/saner/CodeSystem-IHE-ADX-agerange.html)."/>
  <jurisdiction>
    <coding>
      <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/>
      <code value="001"/>
    </coding>
  </jurisdiction>
  <purpose
           value="This code system is defined to support consistent, unambiguous, human- and machine-readable representations of time periods. A primary intended use case is to support the specification of value sets of age ranges for the purposes of data stratification (also referred to as disaggregation)."/>
  <copyright
             value="Adapted from content published by IHE Copyright (c) 2015 [IHE International, Inc](http://www.ihe.net/Governance/#Intellectual_Property). Used here according to the terms of the [CC BY 4 License](https://creativecommons.org/licenses/by/4.0/). Makes use of duration definitions as defined in the [ISO 8601](https://www.iso.org/iso-8601-date-and-time-format.html) specification."/>
  <caseSensitive value="true"/>
  <valueSet
            value="http://terminology.hl7.org/ValueSet/iso-8601-derived-periods"/>
  <compositional value="true"/>
  <content value="not-present"/>
</CodeSystem>