Lots of the people we talk to for the first time are unclear on exactly what master patient index or enterprise master patient index is, let alone why you would need one.  The goal of this post is to provide a jargon-free introduction to the technology.  It’s a monster topic, so we’ll probably just scratch the surface.  I hope you find it helpful!


Master Patient Index vs. Enterprise Master Patient Index

The terms “Master Patient Index” and “Enterprise Master Patient Index” get thrown around interchangeably, which is OK most of the time.  Here is a little clarification:


Master Patient Index (or MPI) can refer to a single registration system and all of its patients. It is also used as short-hand for Enterprise Master Patient Index (or eMPI), which is a database that brings together patient records from multiple registration systems.  This post is focused on the latter use of the term.


What does it do?

There are are two core things that any Master Patient Index has to do:


1. Make sure that registration data is clean and free of duplicate records.

2. Connect the dots for patient records that are split across more than one registration system.


How does it work?

Patient Registration data is replicated to the MPI in real-time from each registration system.  Here are the data elements commonly included:


–  Patient (including medical record number, name, address, phone, SSN, etc)

–  Visit (location, visit date, account number)

–  Insurance

–  Providers

–  Related people


Scanning for Matches

MPI constantly looks for Duplicates (more than one record for the same patient in a single registration system) and Links (when the same patient exists in multiple registration systems.)


Matching is handled by algorithms that locate and assess the quality of matches even when demographic information is missing or wrong.  Match candidates are classified in one of three categories:

–  Automatic-Yes: No research required to confirm that records belong to the same patient

–  Automatic-No: No research required to confirm that records are NOT the same patient, though they may appear similar

–  Maybe: Research is required to confirm whether the records belong to the same patient or not


Task Management

When match decisions cannot be made automatically, tasks are generated so that a human being can get involved to do research.  It is pretty common to have a lot of tasks at first, so the ability to prioritize tasks is important.  You might want to prioritize active patients, certain patient groups, or certain registration areas.


Coaching and Reporting

The ability to measure progress on Data Integrity is super important, so is the ability to help people improve.  Here are a couple of examples:


Registration Coaching

–  How many Duplicate records did each registrar create, considering the number of patients she or he registers?

–  Did the Registrar have enough information to make a good identity decision?

Medical Records

–  Decision Auditing – Do trainees understand your data integrity policies and the process?

–  Aging reports – Are Tasks getting completed on time?



eMPI can do way more than match patient records.  Ours does, at least 🙂  Here are some of the other things you can do once it is in place:

–  Keep registration systems in sync, making sure registration updates captured by the hospital are reflected in the ambulatory system, for example.

–  Locate patient history outside of the EMR

–  Prevent HL7 order interfaces from creating Duplicates

–  Raise alerts when patients you are following present at the hospital



Join us for our next upcoming webinar


Intro to Patient Identity and Master Patient Index

June 7th, 2018 at 12:30PM CT





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