This file provides a standardized way of assoc iating alternative  from various schemes with .

At any point in time , an alternative within a particular scheme will be associated with one and only one . A may be associated with zero or mor e alternative within a single scheme.

It is important to note that the and it' s alternative all identify precisely the same real-world object.

Note: The Identifier file is not currently used in the as use of the more flexible structure is preferred for links to alternative codes. The only known current use of this file is for internal identification of components during the content development process.

Identifier file - Detailed Specification

Only one record with the same and fields will be current at any point in time. The current record will be the one with the most recent effectiveTime before or equal to the point in time under consideration.

If the field of this record is false ('0'), then the association is at that point in time. If the field is true ('1'), then there is an identity at that point in time between the  (a ) and the alternateIdentifier in the scheme identified by .