---
type: "datatype"
title: "Period"
datatype: "Period"
---
# Period

- [Datatypes](/datatypes)
- [Definitions](/datatypes-definitions#Period)
- [Examples](/datatypes-examples#Period)
- [Mappings](/datatypes-mappings#Period)
- [Profiles](/datatypes-profiles#Period)

## Overview

See also [Examples](datatypes-examples#Period), [Detailed Descriptions](datatypes-definitions#Period), [Mappings](datatypes-mappings#Period), [Profiles](datatypes-profiles#Period) and [Extensions]([%extensions-location%]extensions-datatypes#Period)

A time period defined by a start and end date/time.

A period specifies a range of times. The context of use will specify whether the entire range applies (e.g., "the patient was an inpatient of the hospital for this time range") or one value from the period applies (e.g., "give to the patient between 2 and 4 pm on 24-Jun 2013").

\[%dt Period 7%\]

If the `start` element is missing, the start of the period is not known. If the `end` element is missing, it means that the period is ongoing. Alternatively, this may be represented by having an explicit end in the future, in which case this means the period is expected/planned to end at the specified time.

The end value includes any matching date/time. For example, the period 2011-05-23 to 2011-05-27 includes all the times from the start of the 23rd May through to the end of the 27th of May.

**Constraints**

\[%dt.constraints Period%\]

Period is used in the following places: \[%dtusage Period%\]

## Elements

- **[Period.start](/datatypes-definitions#Period.start)** [0..1]: [dateTime](/dateTime) The start of the period. The boundary is inclusive.
- **[Period.end](/datatypes-definitions#Period.end)** [0..1]: [dateTime](/dateTime) The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time

## Comments

- **Period.start**: If the low element is missing, the meaning is that the low boundary is not known.
- **Period.end**: The end value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03

## Order and Missing Meaning

- **Period.end**: Missing: If the end of the period is missing, it means that the period is ongoing

## Mappings

- **Period.start**: RIM Mapping: ./low
- **Period.start**: v2 Mapping: DR.1
- **Period.end**: RIM Mapping: ./high
- **Period.end**: v2 Mapping: DR.2