Enterprise Master Patient Index

An enterprise master patient index or enterprise-wide master patient index) is a database that is used across a healthcare organization to maintain consistent, accurate and current demographic and essential medical data on the patients seen and managed within its various departments. The patient is assigned a unique identifier that is used to refer to this patient across the enterprise. The objective is to ensure that each patient is represented only once across all the software systems used within the organization. The essential patient data includes name, gender, date of birth, race and ethnicity, social security number, current address and contact information, insurance information, current diagnoses, most recent date of hospital admission and discharge (if applicable), etc.

EMPIs are intended to solve the common problem where multiple systems across the organization gradually become inconsistent with respect to the patient's most current data when the patient's information changes, and only one system is updated, i.e., the changes are not propagated to the others. A similar problem may be seen for non-healthcare organizations with respect to customer data.

Many software vendors use EMPI and MPI (master patient index) synonymously, because an MPI is only workable if it is used by all software applications across an entire enterprise: that is, "master" implies enterprise-wide scope.