XDS Merge Patient Identifiers Supplement - Discussion

History

The current Supplement represents the third design of an answer to the question of how to handle Merge Patient Identifier (A40) messages from the Patient Identity Feed. First some terminology. The Merge message provides two patient identifiers: MRG-1, the identifier that is going away (being merged into the other) which we call the subsumed patient identifier in this Supplement. The other patient identifier, PID-3, is the identifier that will continue to be used which we call the remaining patient identifier.

The first design attempted to record in registry metadata detailed results of the merge. This used the existing Document Replace mechanism (RPLC Association type) to replace all XDSDocumentEntry objects belonging to the subsumed patient identifier with new XDSDocumentEntry objects which carried the remaining patient identifier. The subsumed and remaining versions of the XDSDocumentEntry referenced the same URI in the Repository. Actually, the two copies of the object were identical except for the XDSDocumentEntry.PatientId attribute. This design went well until we considered the impact on Document Replace, Transformation, Addendum submissions. The process of replacing an entire tree of metadata representing the life cycle of the document with new metadata representing the new patient identifier was too complicated. The two uses of Document Replace brought too many conflicts.

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