Instance Identifier (II)

Instance Identifier (II)

This data type identifies instances of classes like observations or entities (persons, organizations). Attributes are

Attribute	DT	Conf	Description
@extension	st	O	Identification
@root	uid	R	Source of identification

<id extension="13234453645" root="2.16.840.1.113883.2.6.15.3.427.1"/>

The @root attribute is of type OID (object identifier), a unique identifier of the issuing authority or system.

Example

For example, a patient with a patient number 13234453645 created by a specific healthcare provider organization is uniquely identified by the number itself in @extension and the OID of the organization or the sending system, in the example 2.16.840.1.113883.2.6.15.3.427.1 in @root.

In some cases a single OID identifies an object uniquely. In that situation, only @root is populated and @extension is omitted.

Constraints dtr1-1-II: @root is required if @nullFlavor is not present dtr1-2-II: @root may not be used if @nullFlavor is present dtr1-3-II: (deprecated) @extension may not be used if @nullFlavor is present dtr1-4-II: @identifierName may not be used if @nullFlavor is present dtr1-5-II: @displayable may not be used if @nullFlavor is present dtr1-6-II: @reliability may not be used if @nullFlavor is present dtr1-7-II: @assigningAuthorityName may not be used if @nullFlavor is present dtr1-8-II: @root should not be longer than 128 characters. Please write a note to the authors of this rule if this is found to be not sufficient dtr1-9-II: @extension should not be longer than 64 characters. Please write a note to the authors of this rule if this is found to be not sufficient dtr1-10-II: @root shall be a syntactically correct OID or UUID

DICOM has a max of 64 chars in an OID, Canada uses 200 chars for OIDs.