VUHID & EMPIs
The VUHID system works with the Enterprise Master Person Index (EMPI) systems that are the core of RHIO and HIE patient identity management. EMPIs triage accurate patient identification and the sharing of clinical information among participating care delivery organizations. Figure 4 shows how EMPIs link hospitals, clinics, physicians' offices and other medical organizations within a region. The VUHID system communicates directly with the EMPI which in turn interacts with other clinical and administrative systems in the RHIO or HIE.
Figure 4: RHIOs and HIEs use EMPIs for patient identity management
Patients treated in a clinic, physician's office or hospital are assigned "internal" identification numbers for local billing and medical records processing. In fact, they may be assigned multiple numbers — one for radiology tests, another for laboratory tests, a third for billing purposes and a fourth for quality assurance reporting. It is the EMPI's job to keep all these identification numbers straight. It does this by providing two key functions that make clinical information sharing possible 1) demographic matching and 2) identifier cross-mapping. To perform demographic matching, EMPIs gather key "demographic" information about each patient, such as name, date of birth, mother's maiden name, address, social security number, telephone number, etc. This data is compared using probabilistic techniques to data stored in the EMPI database to determine if there are matching records. This is the EMPI "demographic matching" function. If a match is found, this information is used to link to clinical information across the various medical facilities that are part of the RHIO/HIE.
Once the EMPI has identified the patient using demographic matching, it can then go about mapping the various identifiers that have been created for that patient across all the medical facilities that are part of its domain. This is the EMPI "cross-mapping" function.
Thus, the EMPI "knows" the patient even if he or she is represented by many different identifiers in many different situations or locations. Because of this capability, when a new VUHID identifier is assigned, it is the EMPI that ensures that this new identifier will be properly cross-linked to all existing identifiers. As a result, it is possible for the VUHID/EMPI combination to create a comprehensive medical record across participating provider sites despite the fact that patient information is tagged by many different identifiers.