A unique number or set of characters that is applicable to only one ACTIVITY for a PATIENT within an ORGANISATION.

As these are often locally generated at present, they will not be unique in their own right, but as the NHS moves towards central systems, new ACTIVITY IDENTIFIERS should become enough to identify an ACTIVITY without knowing the PATIENT or ORGANISATION.

This attribute is also known by these names:

Context	Alias
plural	ACTIVITY IDENTIFIERS