What is HL7 FHIR?

Beth Plumptre
April 21, 2023

As the world accelerates faster into the digital age, healthcare innovators are constantly pioneering ways for technology to improve the care delivery process. In particular, focus is on health information exchange and how digitization can drive this sector into modern times. Since 1987, Health Level Seven International (HL7), a standards development organization, has designed the framework for transferring electronic information across health systems. This structure is codified in protocols called Health Level Seven (HL7) which set a template for exchanging data between information systems.

Earlier versions of HL7 — HL7 V2 and 3 — are to thank for kicking healthcare interoperability into gear. But with legacy systems operating on unstructured data and within limited scopes, the Fast Healthcare Interoperability Resources (FHIR, pronounced ‘fire’) upgrade in 2014 became a necessary update to bring information exchange into the future.

Today, FHIR is one of the most widely used information exchange standards. In 2019, 84% of hospitals and 61% of clinicians adopted FHIR-enabled technology in their processes. This guide will introduce FHIR and examine why this standard is mapping out the future of healthcare interoperability. Read on to learn about FHIR benefits for information exchange, plus the next steps necessary for its widespread adoption across the healthcare industry.

Why was HL7 FHIR Created?

FHIR protocols are designed to ‘fire’ charge medical data exchange using the power of the internet. To achieve this, FHIR technology is widely accessible, and easily implemented across health systems using standard web technologies like RESTful services, HTTP, and JSON — widely understood frameworks for communicating between devices and systems, regardless of programming language or other technologies.

Pre-HL7, information exchange was mainly in the unstandardized wild west. With no universal formats for data sharing, players had free reign to develop their health record structures privately, using software technology and data formats that weren’t always compatible with other operating systems. For example, one provider could have valuable patient information siloed and out of reach from another player looking to collaborate toward a patient’s continued care. As a workaround, earlier HL7 architecture supported point-to-point interfaces which built unique structures for one computer to talk to and exchange information with another. This meant to identify a patient’s previous lab results or other clinical information, a requesting health facility and the answering vendor would first determine the data format both operating systems could use and understand. Their integration teams would then establish a secure connection to protect the data, before developing a custom interface for this exchange — a costly and often time-consuming process.

FHIR intervenes to simplify information exchange dramatically — everything from lab notes, CT scan images, and information from wearables, remote monitoring devices, etc, can be compressed into FHIR-compatible formats, and exchanged seamlessly using enabled APIs. As data use and consumption continues to explode across healthcare — around 30% of data produced worldwide is generated by the healthcare industry — streamlined exchange is a top priority to enforce continuity of care. FHIR standards operate on snippets of data called resources, which are then accessed using URLs or RESTful APIs — all of which we’ll be examining next.

How does FHIR Work?

Under FHIR’s hood, you’ll find the entire protocol structure built on tiny blocks of information called resources. These resources are connected to APIs that use common internet tools, and can work seamlessly with web-based services to transfer information. Resources and FHIR-APIs are developed on data-sharing formats of older HL7 versions like messaging and document sharing.


Resources contain the most used elements in a given concept. For instance, a financial resource can carry billing and payment data, while patient resources hold records on name, date of birth, medical conditions, etc. There are about 150 resources on common healthcare concepts like observation, medication, encounters, and so on, which any vendor’s software or system can use, and can be accessed using a simple URL, just like a website.

These technologies provide a standardized way for systems to communicate over the internet. Consider these protocols vendor-agnostic technologies, providing a backdoor for systems to communicate when different programming languages and other technologies might confuse how data is transmitted and received.


FHIR APIs act as middlemen for the information contained in resources to be queried and retrieved using efficient one-to-many connection points. While former exchange systems required point-to-point endpoints between two vendors looking to exchange valuable health data, a single API can exchange information between multiple systems with ease.

This means a hospital can do away with custom interfaces with every pharmacy, laboratory, clinic, and other provider requiring access to patient records. Using APIs, a hospital would simply set up a server containing health information as FHIR resources. It would then set up an FHIR-API as a central database of sorts, where authorized external systems can plug in to access electronic health records. Pharmacies, labs, and other vendors would simply need to configure their FHIR-compatible APIs to interface with the hospital. Furthermore, patients and other partners can search for, update, retrieve, or delete health information with the right authorizations using APIs.

Resources and APIs for interoperability

With standardized data sets in place, FHIR-APIs do a lot of behind-the-scenes heavy lifting to ensure other stumbling blocks to interoperability are out of the way. Because FHIR-APIs are built on familiar RESTful architecture, this lowers the barrier for entry to developers without prior healthcare experience, who can now easily integrate FHIR-compatible applications into servers. This easy integration ensures that newer healthcare domains like mobile health applications, wearables, patient monitoring devices, etc, can access and exchange health records without complicated or custom interfaces.

FHIR also introduces a layer of security for data exchange using Substitutable Medical Applications Reusable Technologies (SMART), an open-source API that guarantees secure access to EHRs using OAuth to authenticate and authorize user access. As impressive as these features are, HL7 continues optimizing FHIR protocols to promote interoperability and improved health outcomes.

FHIR Version 4.0, released in 2019, made further interoperability improvements, with a major design upgrade to being backward-compatible. This means future HL7 versions can work with past FHIR standards without needing to reformat data or other structures. The latest version, 5.0, released on March 23 2023, will also widen interoperable networks. Notably, it will increase the number of resources for health-related information. 

FHIR’s open-sourced structure is leveling the playing field for information access. This way, patients, providers, specialists, pharmacies, and other practitioners have ready access to a patient’s complete health records.

How is FHIR Transforming Healthcare?

FHIR is edging towards the finish line for seamless interoperability in healthcare operations. Since 2020, healthcare providers have been mandated by the ONC Cures Act to exchange data using FHIR-compatible APIs. This wide adoption considers the benefits to patient outcomes, clinical workflows, and data exchange when FHIR-enabled standardization is implemented.

FHIR is transforming the healthcare landscape in the following ways:


FHIR provides the missing link preventing easy communication between IT systems: a common language. FHIR protocols like data models and resources are promoting standard messaging resources between EHRs, Health Information Exchanges, applications, and other vendors.

Improved data management

Remote patient monitoring, wearable technologies, specialist physicians, hospitals, and other health partners are working to reduce hospital readmissions, enhance overall care delivery, and generate considerable data. FHIR provides real-time access to relevant multiple EHR systems, easing the process with standardized and secure technologies.


​​FHIR protocols introduce new ease to integrating decision-support applications into the EHR. As an open-source API using internet technologies, FHIR encourages collaboration between developers who do not need prior healthcare knowledge to create new technologies easily integrated into operating systems to enhance patient care.

Patient-Centered Care

Providers can now personalize therapies using patterns and trends observed from patient data, obtained through FHIR APIs such as Metriport's open-source and universal Medical API, which integrates with the largest Health Information Exchanges in the country.

What’s Next for HL7 FHIR?

FHIR protocols are changing the face of data exchange, and by extension care delivery across healthcare systems. This standard is shaping the future of healthcare technology, and setting the stage for interoperability across health systems that work together to promote patient health.

Get in touch with Metriport today to learn more about how we're making full use of the latest FHIR protocols and advancements in healthcare interoperability.

Stay up-to-date with news from Metriport.

View Blog

Get the latest updates and blog posts from the Metriport team.

Metriport icon