master patient index (MPI)

A master patient index (MPI) is an electronic medical database that holds information on every patient registered at a health care organization.

The MPI stores information like patient name, date of birth, gender, race, social security number and place of residence alongside the patient’s medical history. This provides a clear and complete view of an individual patient and also a large-scale view of the demographics that an HCO is working with.  MPIs ensure that every patient is represented only once, and with constant demographic identification, within all systems of hospital data.  By keeping this data well organized, hospitals can provide more efficient and accurate care for their patients.

An enterprise master patient index (EMPI) is a large index that links several smaller MPIs together, from outpatient clinics to rehabilitation facilities to medical centers. 

Learn more:

The role of master patient index in development of state HIEs.

What technologies and standards are being used in MPI technology?

This was last updated in April 2012
Posted by: Margaret Rouse

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