{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).', package_name: hl7.fhir.uv.cqm, name: ISO8601DerivedPeriodsCodes, type: null, package_version: 1.0.0, class: unknown, kind: null, url: 'http://terminology.hl7.org/CodeSystem/iso-8601-derived-periods', version: 1.0.0}