Implementing a Master Patient Index

Executive Summary

A Master Patient Index (MPI) aims to identify individual patients by storing and analyzing demographic information and assigning a unique identifier to that person. This electronic database holds information in a centrally accessible location for all healthcare providers thus allowing personal healthcare records to be shared more easily and cost-effectively. By following a successful implementation plan used by many in the industry an effective MPI can be established.   

Companion Article

Tools for Designing a Master Patient Index and Other Registries 

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What is a Master Patient Index?

A Master Patient Index (MPI)—also referred to as a patient master index, patient registry, or a client registry— is an electronic database that holds demographic information on every patient who receives healthcare services. The MPI aims to accurately match and link records by uniquely identifying individuals. This is done by storing information such as name, date of birth, gender, etc., and assigning everyone a unique identifier.

MPI Benefits

  • Accurate identification of an individual and their health record quickly when using a health service
    • Maintains a central registry of all patents and their demographics
  • Up to date information anytime and anywhere for access to these services
  • Ensures medical staff have the correct and most up to date health record for the right patient
    • Eliminates duplicate patient registration entries
  • Improves patient safety by reducing risk of error due to misdirection of clinical information
    • Enables healthcare workers to identify which facilities an individual has visited
  • Support the provision of cost-effective and timely health care services



Match individuals based on a combination of the following:

  • Unique patient identifier
  • Patient name
  • Date of birth
  • Gender
  • Race
  • Ethnicity
  • Address
  • Alias/previous name
  • Biometrics such as fingerprints or face recognition
  • National identification number/passport number


Robust Matching Algorithms within the MPI must automatically match and link identifiers for the same patient from different systems, but do so without incorrectly matching records that are not for the same patient. An MPI must employ both deterministic and probabilistic methods to match records. A deterministic method searches for an exact match between attributes, while a probabilistic method searches for an approximate match between two records.


Step 1: Analyse the Current Environment

The assessment supports the identification of problems to be solved, identifies stakeholders, describes what success will look like in a specific environment, and identifies challenges/barriers. This process will lay the groundwork for the implementation of a client registry.

Step 2: Establish Leadership and Ownership

Effective leaders should be identified and join to form a stakeholder leadership group (SLG) for the development and implementation of a Client Registry. The SLG should be the authority under which the Client Registry operates and accepts responsibility to define scope, vet and prioritize use cases/user stories, and ensure agreement on the data specifications used in the Client Registry.

Step 3: Document Specifications and Requirements

A client registry should be responsive to users’ needs and the local context. User stories and data specifications are two ways to describe: “What will the client registry achieve and how should it operate?” A primary objective of this guide is to promote and facilitate a country-driven and user requirements-based process.

Step 4: Implement Specifications

Using the draft specifications and user stories developed in Step 3 as a foundation to move forward, the next step is to determine resources and develop the project plan to support the implementation process of the client registry. This step will include a selection of software, determining hardware needs, defining the patient matching algorithm (for specified use cases), and validation/testing.

Step 5: Create Support Plan

Support strategies should be developed and should remain in place to triage requests for data, system enhancements, integrations, operations support or general troubleshooting among users.

Step 6: Post-Production Evaluation

Post production, it is important to capture lessons learned. Once the system is running and stabilized, the iterative development process can begin again with an expanded scope. New interfaces, user stories or workflows may need to be added.

Example Tool Guides: