· Oct 10, 2023 3m read

Using FHIR Adapter to deliver FHIR services over legacy systems - Introduction

Surely you have all heard about FHIR as the panacea and solution to all interoperability and compatibility problems between systems. Right here we can see one of his classic defenders holding a FHIR resource in his hand and enjoying it immensely:

But for the rest of us mortals we are going to make a small introduction.

What is FHIR?

Let's get straight to the definition: FHIR (Fast Healthcare Interoperability Resource) is an interoperability standard developed by HL7 (Health Level 7 set of standards) designed to enable electronic exchange of healthcare data between different systems in the healthcare industry .


What technologies is FHIR fundamentally based on?

Mainly in the conjunction of HTTP calls via REST API and the JSON format (although it could be XML and any other communication available to us depending on the use we are giving it).


How do we work with FHIR?

Generally, the simplest thing is to have an FHIR server with which we will communicate using HTTP calls such as GET (to obtain data from the server), PUT (to update data), POST (to save data) and DELETE (to delete). .

FHIR handles the concept of Resource that will be used to send and receive data between server and client. These resources aim to cover 80% of the intercommunication needs between systems. Here we can see an image of the resources available by default.

As you can see, each resource is accompanied by a number or letter that indicates the maturity of said resource (where N = normative). If you access the official FHIR documentation you will have access to a multitude of examples.

A development of the Resource is the Bundle, which, in summary, is a set of resources packaged within the same JSON and that is used to make queries about our server as well as perform CRUD operations in batches or transactions.

Perfect, FHIR sounds fantastic, can we apply it to our legacy systems that were not designed to work following the criteria defined by FHIR?


FHIR Adapter

InterSystems makes the FHIR Adapter functionality available to its clients, which will allow them to set up a business layer on top of their legacy systems, developing what is known as FHIR Façade. In the following articles we are going to see how we can work with FHIR objects and interact with a small simulation of what a HIS (Health Information Service) system that uses a PostgreSQL database would be like.

In order to follow the explanations, you have at your disposal an OpenExchange application that will automatically set up the example that we will follow in the coming days:

Development of the workshop

In the next articles we will discuss the following points:

  1. FHIR Adapter architecture in our IRIS instance
  2. Registering a patient type Resource in our HIS.
  3. Querying patients by their ID using a REST API call.
  4. Registering a Bundle with patient and medical center data in our HIS.

So if you are interested... Stay tuned to the Community in the coming days!

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