What is an Enterprise Master Index (EMPI)?

Ashabil Rizhana

Ashabil Rizhana

Operations Manager


What is an Enterprise Master Index (EMPI)?

Hey there! You've probably never spent your lunch break thinking about how hospitals keep track of all their patient data, right? Well, buckle up because we're about to dive into a little story about something called the Enterprise Master Patient Index, or EMPI for short. Imagine a world where every time you visit a hospital, no matter the typo in your name on your record, they could still figure out it's you. That's what an EMPI does - pretty neat, huh?


What's the Big Deal About EMPIs?

So, here's the thing. When a hospital just has one system, managing patient records is a walk in the park. But as soon as you add more systems into the mix, things can get messy. For instance, "Jane Doe" in one system could accidentally become "Jane Do" in another thanks to a typo, and just like that, accessing all of Jane's medical info becomes a game of hide and seek.

This doesn't just make extra work for hospital staff; it can be downright dangerous for patients if vital information goes missing. This is where our superhero, EMPI, comes swooping in. Its job is to chat with all the hospital systems, making sure they’re all telling the same story about each patient. Sophisticated algorithms help link duplicates, ensuring that no matter how many typos are out there, the right John Smith gets the right treatment.


How Does an EMPI Work Exactly?

You're probably wondering how on earth EMPIs pull this off. Well, it all boils down to something called matching rules. These rules are like detectives figuring out that even though "Sidharth" and "Siddarth" look different, they're probably the same person based on other clues like their birthdate.

But here's the kicker, comparing every patient against every other would be like finding a needle in a haystack. So, EMPIs use something called blocking rules. Think of this as telling an EMPI not to compare patients unless they meet certain criteria, like being born in the same state. This way, EMPI can zero in on likely matches without going on a wild goose chase.


Algorithms to the Rescue!

And how does an EMPI get so smart about spotting matches? Thanks to some clever algorithms. For names, we've got things like the Jaro-Winkler algorithm, which measures how many changes you need to make to one string to get another. Then there's the Metaphone algorithm, focusing on how a name sounds rather than how it's spelled.

Let's take the name, "Sidharth", as an example. Depending on how it's entered, we could have several variations. However, by using these algorithms, EMPIs can see through the discrepancies and link the records correctly. Cool, right?

You can play around with various similar sounding names on this Metaphone Generator that I came across.


Create your own EMPI with Open Source Tools

Now for the cherry on top: you can experiment with your very own EMPI system using free tools like OpenEMPI and open-source projects like the HAPI FHIR server. OpenEMPI is a Java project that gives you the gist of how an EMPI operates. Meanwhile, the HAPI FHIR server's MDM (Master Data Management) module lets you dive into the nitty-gritty of configuring these matching and blocking rules for FHIR patient resources.

Additionally, if you want to learn how to set up your own HAPI FHIR server, check out this YouTube video.


Taking the Leap

So there you have it, a crash course on EMPIs and how they ensure that your medical records are always matched up correctly, no matter how many times someone misspells your name. It's a complex process made simpler through some pretty cool tech. And if you're feeling adventurous, why not take OpenEMPI or HAPI FHIR's MDM module out for a spin? Who knows, you might fall in love with the world of health tech development. Thanks for sticking around, and I'll catch you in the next one!




1. What is EMPI? 

An EMPI stands for Enterprise Master Patient Index. It is a software service in a healthcare infrastructure that takes care of linking and deduplicating patient records across multiple distinct healthcare applications and facilities.


2. What is the purpose of the Enterprise Master Patient Index within an EHR system? 

An EMPI ensures that all the patient’s records can be retrieved even if there are mistakes made in the name or identifier of the patient on different applications. An EMPI is responsible for having a single source-of-truth representation of the digital patient record for every real-world patient.


3. What to do after downloading the open-source tool from openempi.org?

The OpenEMPI application is a Java application. It needs to be run in a Tomcat environment. Only the versions below 3.6 are still open-source. The installation instructions for these versions can be found here.


4. What is the difference between MPI and EMPI?

While an MPI or Master Patient Index takes care of all patient records in a single facility or application, an EMPI works across distributed applications, facilities, or databases. In a sense, an EMPI has a federated architecture to work with multiple applications using protocols defined by a standards body, commonly IHE. 


5. What is MRN? Is EMPI the same as MRN?

MRN stands for Medical Record Number. It is a unique identifier given by a healthcare facility to a patient. An EMPI on the other hand is a software system that makes it possible to store, link, and maintain patient records - including details like their identifiers where MRN can be one such identifier. The EMPI may of course use other identifiers like Social Security Number, Driving License, and Passport number for identification purposes.


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