| # | | Name | Source | Ver | Description |
| 1 | | Date Accuracy Indicator | hl7.fhir.au.base#current | R4 | This extension applies to the [date](http://hl7.org/fhir/R4/datatypes.html#date) and [dateTime](http://hl7.org/fhir/R4/datatypes.html#dateTime) data types and is used to represent the accuracy of the associated date. |
| 2 | | EEBase Date Accuracy Indicator | hl7.fhir.ee.base#current | R5 | This extension applies to the [date](http://hl7.org/fhir/datatypes.html#date) and [dateTime](http://hl7.org/fhir/datatypes.html#dateTime) data types and is used to represent the accuracy of the associated date. |
| 3 | | Extension - Date Day | hl7.fhir.us.vrsandbox#current | R4 | The day portion (DD) of the partial date. |
| 4 | | Extension - Date Day | hl7.fhir.us.mdi#current | R4 | The day portion (DD) of the partial date. |
| 5 | | Extension - Date Day - Vital Records | hl7.fhir.us.vr-common-library#current | R4 | This Extension profile represents the day portion (DD) of the partial date. |
| 6 | | Extension - Date Month | hl7.fhir.us.vrsandbox#current | R4 | The month portion (MM) of the partial date. |
| 7 | | Extension - Date Month | hl7.fhir.us.mdi#current | R4 | The month portion (MM) of the partial date. |
| 8 | | Extension - Date Month - Vital Records | hl7.fhir.us.vr-common-library#current | R4 | This Extension profile represents the month portion (MM) of the partial date. |
| 9 | | Extension - Date Time | hl7.fhir.us.vrsandbox#current | R4 | The time portion (DD) of the partial date. |
| 10 | | Extension - Date Time | hl7.fhir.us.mdi#current | R4 | The time portion (DD) of the partial date. |
| 11 | | Extension - Date Time - Vital Records | hl7.fhir.us.vr-common-library#current | R4 | This Extension profile represents the time portion (DD) of the partial date. |
| 12 | | Extension - Date Year | hl7.fhir.us.mdi#current | R4 | The year portion (YYYY) of the partial date.
The MDI Extension - Date Year artifact overlaps with the VRDR Date Year artifact. |
| 13 | | Extension - Date Year - Vital Records | hl7.fhir.us.vr-common-library#current | R4 | This Extension profile represents the year portion (YYYY) of the partial date. |
| 14 | | Extension - Partial Date - Vital Records | hl7.fhir.us.vr-common-library#current | R4 | This Extension profile represents values of a partial date. |
| 15 | | Extension - Partial DateTime | hl7.fhir.us.mdi#current | R4 | Provides values of a partial dateTime |
| 16 | | Extension - Partial DateTime | hl7.fhir.us.vrsandbox#current | R4 | Provides values of a partial dateTime |
| 17 | | Extension - Partial DateTime - Vital Records | hl7.fhir.us.vr-common-library#current | R4 | This Extension profile represents Provides values of a partial dateTime |
| 18 | | Partial Date | hl7.fhir.us.vrsandbox#current | R4 | Provides values of a partial date (Extension) |
| 19 | | Partial Date | hl7.fhir.us.vrdr#current | R4 | Provides values of a partial date (Extension) |
| 20 | | Partial Date Time | hl7.fhir.us.vrsandbox#current | R4 | Provides values of a partial dateTime (Extension) |
| 21 | | Partial Date Time | hl7.fhir.us.vrsandbox#current | R4 | Provides values of a partial dateTime (Extension).
If a component is missing, it is assumed unknown.
* This extension SHOULD NOT be used when the value can be expressed as a [dateTime](https://build.fhir.org/datatypes.html#dateTime), specifically YYYY, YYYY-MM, YYYY-MM-DD, or a full dateTime.
* This extension SHOULD NOT be used to express that the dateTime in its entirety is missing/unknown. In this case a simple dataAbsent reason extension should be used on the dateTime.
* This extension SHOULD be used to express missing components of dateTime including XXXX-XX-DD, YYYY-XX-DD, YYYY-MM-XX, as well as all cases where the time is known, but one or more components of the date is unknown.
* If a component is missing, the interpretation should be equivalent to it being present, with a data absent reason of 'unknown'. If the data absent reason is other than 'unknown', the component may be included wih a data absent reason.
When the known components of the date can be expressed as a valid dateTime, the value SHALL be present. So, for example 2022-12-XX-1201212, the dateTime value should be "2022-12". |
| 22 | | Partial Date Time | hl7.fhir.us.vrdr#current | R4 | Provides values of a partial dateTime (Extension) |
| 23 | | Relative Date Criteria | hl7.fhir.uv.extensions.r4#1.0.0 | R4 | Specifies that a date is relative to some event. The event happens [Duration] after [Event]. |
| 24 | | Rendered Value | hl7.fhir.uv.extensions.r4#1.0.0 | R4 | Provides a rendered version of the value intended for human display. For example, a sensitive identifier (e.g. social security number) partially obscured by asterisks; a drivers licence number with dashes inserted; a date formatted as MMM dd, yyyy; etc. |
| 25 | | Timezone Code | hl7.fhir.uv.extensions.r4#1.0.0 | R4 | An IANA timezone code for the timezone offset per [BCP 175](https://www.iana.org/go/rfc6557). The offset is specified as part of a dateTime/instant (or using the tzOffset extension on a date if necessary). The timezone code may also be provided to allow for human display of the location associated with the offset. |
| 26 | | Uncertain date | hl7.fhir.uv.extensions.r4#1.0.0 | R4 | When present, this extension indicates that the date of a period start or end is uncertain and falls within its own period. |
| 27 | | Uncertain period | hl7.fhir.uv.extensions.r4#1.0.0 | R4 | Used to express an uncertain date(+time) value by specifying an allowed or observed upper and lower bound. |