Format/length:	an35
HES item:
National Codes:
Default Codes:

Notes:

Definition:
A CDS data element providing a unique identity for the life-time of an episode carried in a CDS message.
The CDS UNIQUE IDENTIFIER has three components. The recommended constructs are given below.
For All CDS Types EXCEPT the EAL CDS Types:

REF	UID	FORMAT	CODES / VALUES	COMMENT
1	NHS Organisation Code Type	an1	A = Pre 1996 Organisation Code B = Post 1996 NHS Organisation Code	Mandatory For all CDS Types
2	Provider Code	an5	The NHS Organisation Code of the Provider at the time of, or at the start of, the period covered by the activity reported by the CDS Message.	Mandatory for all CDS Types
3a	Application Specific CDS Identity	an29	A code of up to 29 alpha-numeric characters generated by the Sender's application to uniquely identify the CDS within its CDS Type or family of CDS Types	Mandatory for all CDS Types Except for EAL CDS Types

For EAL End Of Period (EOP) CDS Types only:

REF	UID	FORMAT	CODES / VALUES	COMMENT
1	NHS Organisation Code Type	an1	A = Pre 1996 Organisation Code B = Post 1996 NHS Organisation Code	Mandatory For all CDS Types
2	Provider Code	an5	The NHS Organisation Code of the Provider at the time of, or at the start of, the period covered by the activity reported by the CDS Message.	Mandatory for all CDS Types
3b	Application Specific CDS Identity	an9	A code of up to 9 alpha-numeric characters generated by the Sender's application to uniquely identify the EAL End Of period census CDS Types with the same Admission List Entry. Additional data positions must be left blank.	Mandatory for all EAL EOP CDS Types
3c	Filler	an20	Additional data positions must be left blank.

For EAL Event During Period (EDP) CDS Types only:

REF	UID	FORMAT	CODES / VALUES	COMMENT
1	NHS Organisation Code Type	an1	A = Pre 1996 Organisation Code B = Post 1996 NHS Organisation Code	Mandatory For all CDS Types
2	Provider Code	an5	The NHS Organisation Code of the Provider at the time of, or at the start of, the period covered by the activity reported by the CDS Message.	Mandatory for all CDS Types
3d	Application Specific CDS Identity	an9	A code of up to 5 alpha-numeric characters padded with 4 trailing spaces to 9 characters. Generated by the Sender's application to uniquely identify the EAL End Of period census CDS Types with the same Admission List Entry.	Mandatory for all EAL EOP CDS Types
3e	Filler	an3	A code of 3 alpha-numeric characters generated by the Sender's application to identify the event within the EAL Entry. Even if the events are of different types, they must have different identifiers.	Mandatory for all EAL EDP CDS Types
3f	Filler	an17	Additional data positions must be left blank.

Usage:
This is a mandatory data item when the Net Change Update Mechanism is used and strongly recommended for use with the Bulk Replacement Update Mechanism.
1. Note that senders of CDS data remain directly responsible for the integrity of the CDS UID.
2. The first two components, the NHS Organisation Code Type and the Provider Code, are required for all CDS Types.
3. It is a mandatory requirement for all submissions using the Net Change Update Mechanism that these two components are constructed correctly to ensure uniqueness of the CDS UID across the NHS.
4. The structure of 3b and 3c allows the EAL End of Period Census and the EAL Event During Period Census for the same EAL Entry to be linked.

There are circumstances in PAS/CASEMIX application systems where the control of the UID key integrity may be suspect. These issues include:
a) Episode deletion (not resulting in a CDS deletion sent to the Commissioner);
b) Episode re-sequencing (not resulting in a corresponding CDS being sent);
c) Service agreement alterations not resulting in correct adjustments - Old Service Agreement deletion / New Service Agreement addition
d) Re-admissions causing duplicate keys on the ClearNET database.

The NWCS User Guide contains further details regarding the management and use of the CDS UNIQUE IDENTIFIER.