Master Patient Index (MPI)


Master Patient Index (MPI) is a database that maintains a unique index (or identifier) for every patient registered at a health care organization. The MPI is used by each registration application (or process) within the HCO to ensure a patient is logically represented only once and with the same set of registration demographic / registration data in all systems and at an organizational level. It can be used as enterprise tool to assure that vital clinical and demographic information can be cross-referenced between different facilities in a health care system ( see fig. 1). A MPI correlates and cross-references patient identifiers and performs a matching function with high accuracy in an unattended mode. A MPI is considered an important resource in a healthcare facility because it is the link tracking patient, person, or member activity within an organization (or enterprise) and across patient care settings.

According to the American Health Information Management Association (AHIMA), some recommended core data elements for indexing and searching records include:
  • Internal patient Identification
  • Patient Name
  • DOB
  • DOB qualifier
  • Gender
  • Race
  • Ethnicity
  • Address
  • Alias/pervious name
  • SS#
  • Facility identification
  • Universal patient identifier (if available)
  • Account number
  • Admission date
  • Discharge date
  • Service type
  • Patient disposition


An Enterprise Master Patient Index (EMPI) is a database that contains a unique identifier for every patient in the enterprise. This would include the medical center, outpatient clinics, practice offices and rehabilitation facilities. An EMPI cross references patient identifiers across multiple information systems to uniquely identify each patient, perform global patient searches and matching, consolidate duplicate patient records, create complete views of patient information and share data across multiple facilities and information systems in real time ( see fig. 2 and 3). The following lists a few software companies and their matching softwares:


Web Resources:

U.S. Department of Health and Human Services
What is an EMPI?
Matching records in a national medical patient index
IBM healthcare

Related Terminology:

Master Person Index
Patient Master Index
Enterprise Master Person Index


Fig. 1
external image eckma1.jpg

Fig. 2
external image PracticPartner.jpg

Fig. 3