The sequence of numbers and/or letters which comprise a PRIMARY IDENTIFIERS. The primary identifier for a PERSON (eg. new NHS Number). The PRIMARY IDENTIFIERS determines the sub-type of PERSON.

Note: the field length is a maximum. The types of PRIMARY IDENTIFIERS determine the code length, e.g. Code for General Practitioner will always be 8 characters. 

This attribute is also known by these names:

Context	Alias
plural	PRIMARY IDENTIFIERS