The MatchMerge Identity Resolution Service provides the foundation for matching an individual's medical records from different sources and merging them into a meaningful medical information profile for that person.   

Identity resolution provides two basic operations for accessing a cross-referencing index of person identifiers and identifying information (commonly known as a Master Person Index (MPI):  

• Register allows a person's identity to be known to the service;
• Query allows the index to be searched.

The user screen from the San Diego Immunization Registry (SDIR) illustrates the search operation of the MatchMerge Identity Resolution Service:

This screen illustrates the retrieved person record.  Note the top section shows the person identifier and demographics that was previously supplied by the user's organization through a Register operation.  The bottom half of the screen shows information (limited by confidentiality policy) about any linked identifiers and demographics supplied by another source.