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: ISO-8601-Derived Periods - JSON Representation

Active as of 2025-06-27

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{
  "resourceType" : "CodeSystem",
  "id" : "iso-8601-derived-periods",
  "text" : {
    "status" : "generated",
    "div" : "<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/fhir/CodeSystem/iso-8601-derived-periods</code> defines codes, but no codes are represented here</p></div>"
  },
  "extension" : [
    {
      "url" : "http://hl7.org/fhir/StructureDefinition/structuredefinition-wg",
      "valueCode" : "cqi"
    }
  ],
  "url" : "http://terminology.hl7.org/fhir/CodeSystem/iso-8601-derived-periods",
  "version" : "1.0.0",
  "name" : "ISO8601DerivedPeriods",
  "title" : "ISO-8601-Derived Periods",
  "status" : "active",
  "experimental" : false,
  "date" : "2025-06-27",
  "publisher" : "HL7 International Clinical Quality Information Work Group",
  "contact" : [
    {
      "telecom" : [
        {
          "system" : "url",
          "value" : "http://hl7.org/Special/committees/cqi"
        }
      ]
    },
    {
      "telecom" : [
        {
          "system" : "email",
          "value" : "cqi@lists.hl7.org"
        }
      ]
    }
  ],
  "description" : "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.\n\nCodes in the code system are defined according to the grammar:\n\nAn 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.\n\nFor example, the age range \"1-9 years\" means everyone who is at least one year old and less than 10 years old represented as `P1Y--P10Y`. The age range \"10-14 years\" means everyone who is at least 10 years old and less than 15 years old and is represented as `P10Y--P15Y`.\n\nDurations 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:\n\n* `P` is the duration designator (for period) placed at the start of the duration representation.\n\t* `Y` is the year designator that follows the value for the number of years.\n\t* `M` is the month designator that follows the value for the number of months.\n\t* `W` is the week designator that follows the value for the number of weeks.\n\t* `D` is the day designator that follows the value for the number of days.\n* `T` is the time designator that precedes the time components of the representation.\n\t* `H` is the hour designator that follows the value for the number of hours.\n\t* `M` is the minute designator that follows the value for the number of minutes.\n\t* `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)\n\nFor example, `P3Y6M4DT12H30M5S` represents a duration of _three years, six months, four days, twelve hours, thirty minutes, and five seconds_.\n\nDate 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.\n\nNote 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_.\n\nContent 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" : "http://unstats.un.org/unsd/methods/m49/m49.htm",
          "code" : "001"
        }
      ]
    }
  ],
  "purpose" : "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" : "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" : true,
  "valueSet" : "http://terminology.hl7.org/ValueSet/iso-8601-derived-periods",
  "compositional" : true,
  "content" : "not-present"
}