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Custom Subject and Item Naming Conventions

The CCOW standard allows individual organizations to define custom subjects or custom items for standard subjects. Custom subjects and items need to follow the data definitions and mandatory naming convention rules specified in the document Health Level-Seven Standard Context Management Specification, Subject Data Definitions.

The general scheme is to add a meta-descriptor as a prefix to the subject or item name. This unique descriptor should use the organization's World Wide Web Consortium (W3C) domain name. An example of a custom subject, shown as having been defined by Medicor Imaging, is:

[medicorimaging.com]DateRange

An example of an item within a custom subject is:
[medicorimaging.com]DateRange.id.[ medicorimaging.com]StartDate

An example of a custom item within the standard patient subject, shown as defined by GE/Marquette Medical Systems:
Patient.Co.[mei.com]Current_medications

The descriptor can be omitted when the desired descriptor can be inferred from the following rules:

1. The default descriptor is [hl7.org].
2. The subject descriptor shall serve for all items within the subject unless an item name contains a descriptor different from the one used with the item's subject name.
3. The context manager shall omit descriptors, including [hl7.org], from the subject name and/or item names of any items it returns to its clients whenever the descriptor can be inferred.
4. A context participant may optionally use descriptors when accessing the context data even when the descriptor could otherwise be inferred.

An organization can define custom items for a custom subject defined by another organization. The following examples denote three different items for the same custom subject:
[medicorimaging.com]DateRange.id.[ medicorimaging.com]StartDate
[medicorimaging.com]DateRange.id.[mipacs.com]EndDate
[medicorimaging.com]DateRange.id.[mipacs.com]StartDate

Note: that the item [medicorimaging.com]DateRange.id.[mipacs.com]StartDate is not the same as [medicorimaging.com]DateRange.id.[ medicorimaging.com]StartDate.