Navigating the Healthcare Data Landscape: HL7, FHIR, and Beyond

The technical side of EMR integration and interoperability with the help of HL7 and FHIR.

Imagine a scenario where a patient is rushed to a new emergency room after a car accident. Their medical history, allergies, and medications are all stored electronically in the ambulance’s system. However, the hospital uses a different healthcare data format, making it difficult for doctors to access this critical information quickly. This delay could impact the quality of care the patient receives.

How to avoid that? 

Healthcare data interoperability refers to the seamless exchange of electronic health information (EHI) between different healthcare systems – hospitals, clinics, pharmacies, and insurance companies.

In this article, we’ll focus on the technical side of EMR integration and interoperability with the help of HL7 and FHIR as two prominent healthcare data exchange standards.

The next two articles will focus on 

  • how we’ve built the system that integrates with EMR with the help of HL7 and FHIR standards – and the challenges we’ve overcome along the way
  • How to create an app for Cerner and Epic Showroom
Check out our previous articles on EHR integration and the organizations that need it.

What is the HL7 Standard?

HL7 stands for Health Level 7 and is a set of international standards established to facilitate the exchange of electronic health information (EHI) between disparate healthcare information systems.

Think of it as a common language that allows different healthcare applications, like electronic health records (EHRs), lab systems, and radiology systems, to “talk” to each other. Developed in the late 1980s, HL7 has become a foundational standard for healthcare data exchange, crucial in promoting interoperability.

HL7 Versions and Key Features

Since the 1980s, when HL7 was first established, the technological advancements have been quite impressive and as a result, HL7 has evolved to address the growing complexities of healthcare data exchange. At the same time, as you’ll see, some things haven’t changed.

Here’s a breakdown of the most prominent versions and their key features:

In one of our projects, we use both HL7 v2 and FHIR as the main standards

HL7 Message Structure and Components

Standards are critical for interoperability. There are Here’s an illustration of the structure and components of an HL7 message:

Imagine a message on a piece of paper. This message follows the HL7 format, which has specific sections to organize the information.

  • Lines: The message is divided into lines, with each line representing a single segment.
  • Segments: Each segment starts with a three-letter code (e.g., PID for Patient Identification) that identifies its purpose.
  • Fields: Segments are further divided into fields, separated by a pipe symbol (“|”). Each field contains specific data elements related to the segment’s purpose.
  • Components: Some fields can be further divided into components, separated by a caret symbol (“^”). Components provide additional details within a field.

Here’s an example of a simplified HL7 message segment (PID – Patient Identification):

PID|||John Doe^^^^^MRN12345||01/01/1980||M||123 Main St^^Anytown^CA^12345^^^^US||(555) 555-1212


  • This is the PID segment identifying a patient, whose name is John Doe in our case.
  • Fields are separated by pipes (“|”).
  • It’s a simple PID and there are no additional components used in this example.

Challenges with HL7

While HL7 is the primary standard around the world for interoperability and medical systems integration, there are certain difficulties associated with it.

Configuration Challenges: Implementing HL7 v2 often requires significant setup within hospitals. Many healthcare institutions, understandably focused on patient care, may prioritize existing, “functional” systems over frequent technology updates.

Interoperability Issues: When integrating data across multiple hospitals, like insurance companies processing reports, a new layer of complexity emerges. Different hospitals may use customized or varied formats within the HL7 v2 framework. These variations require additional mapping and interpretation efforts to ensure accurate patient and case data extraction.

This highlights the need for a more streamlined and adaptable approach to data exchange in healthcare. There is a way to do it more easily: welcome, HL7 FHIR standard that uses JSON.

HL7 FHIR: Advantages and Key Features over HL7 v2

HL7 FHIR (Fast Healthcare Interoperability Resources) has emerged as the next-generation standard for healthcare data exchange, offering several advantages over its predecessor, HL7 v2. Here’s a breakdown of its key features and benefits:

HL7 v2

Relies on complex message structures with specific formats for different types of data.


Employs a more flexible approach by organizing data into discrete, reusable units called resources. These resources represent real-world healthcare concepts like patients, medications, allergies, and appointments.


  • Easier data exchange for a wider range of healthcare data.
  • Improved interoperability with different healthcare systems.
  • Increased flexibility for developers to create custom applications using FHIR resources.
HL7 v2

Uses a complex, structured format with segments, fields, and components, which can be challenging to parse and interpret.


Leverages modern data formats like JSON and XML. These formats are widely used across web technologies, making them easier to integrate with existing systems and develop FHIR-based applications.


  • Reduced development complexity for integrating FHIR with healthcare systems.
  • Improved interoperability with other web-based applications.
  • Easier for developers to understand and work with data.
HL7 v2

HL7 v2 primarily relies on point-to-point messaging protocols.


Utilizes a RESTful API (Application Programming Interface), which is a standardized way to access and exchange data over the web.


  • Easier integration with modern web applications and mobile devices.
  • Improved scalability and flexibility for data exchange.
  • Developers can leverage existing tools and frameworks familiar with RESTful APIs.

We’ve shared an example of an HL7 v2 message segment (PID – Patient Identification) above:

PID|||John Doe^^^^^MRN12345||01/01/1980||M||123 Main St^^Anytown^CA^12345^^^^US||(555) 555-1212

Here is how the same information would look like in HL7 FHIR:

  "resourceType": "Patient",
  "id": "MRN12345",  // Assuming MRN12345 is a unique patient identifier
  "active": true,
  "name": [
      "use": "official",
      "text": "John Doe"
  "telecom": [
      "system": "phone",
      "value": "(555) 555-1212"
  "gender": "male",
  "birthDate": "1980-01-01",
  "address": [
      "use": "home",
      "text": "123 Main St, Anytown, CA 12345, USA"

As you can see, even from a non-tech developer’s point of view, FHIR data seems a lot more understandable and clear as well as simpler to navigate without those ^^ and | signs.

Additional Advantages of FHIR:

  • Standardized Data Model: FHIR builds upon a standardized data model, ensuring consistent representation of healthcare concepts across different systems.
  • Scalability: FHIR can handle a wider range of healthcare data compared to HL7 v2.
  • Evolving Standard: FHIR is actively developed and updated with new features to address evolving healthcare data needs.

Overall, HL7 FHIR offers a more modern, flexible, and user-friendly approach to healthcare data exchange compared to HL7 v2. Its resource-based architecture, modern data formats, and RESTful API make it the preferred standard for future healthcare data interoperability.

Examples of FHIR Resources and their Usage in Healthcare Data Exchange

HL7 FHIR utilizes a rich set of resources to represent various healthcare concepts. Here are some common examples and how they are used in data exchange:

ResourcesWhat’s included?Usage
👩PatientThis core resource captures essential information about a patient, including demographics, identifiers, contact details, allergies, and immunizations.Used to exchange patient data between hospitals, clinics, and other healthcare providers involved in a patient’s care.
💊MedicationThis resource describes a medication, including its name, dosage form, route of administration, and other relevant details.Used to share medication orders, prescriptions, and medication administration records between healthcare providers and pharmacies.
🩻ObservationThis resource represents clinical findings from various sources, such as lab tests, vital signs, imaging studies, and physical examinations.Used to exchange lab results, radiology reports, and other clinical observations across different healthcare systems.
📆EncounterThis resource documents a patient’s interaction with a healthcare provider, including the reason for the encounter, diagnosis codes, and procedures performed.Used to exchange information about patient visits, consultations, and hospital admissions between healthcare settings.
💉ImmunizationThis resource captures the patient’s vaccination history, including the vaccine type, date administered, and dosage.Used to share immunization records for public health reporting and ensuring patients receive appropriate vaccinations.
FHIR Resource Data Examples

Benefits of Resource-Based Approach:

  • These are just a few examples, and FHIR offers a vast library of resources to represent various healthcare entities.
  • The resource-based approach allows for modular data exchange, where specific resources can be exchanged depending on the information needs.
  • This flexibility and standardization facilitate seamless data exchange and improve interoperability between different healthcare systems.

FHIR is being used in various healthcare applications like patient portals, telehealth platforms, and clinical decision support systems. By enabling secure and standardized data exchange, FHIR empowers healthcare providers to deliver more coordinated and efficient patient care.

Benefits of FHIR

HL7 FHIR has emerged as a game-changer in healthcare data exchange, offering significant advantages compared to its predecessors. Let’s delve deeper into the benefits of FHIR and explore its potential to revolutionize healthcare.

1. Flexibility and Ease of Implementation:

  • Modular Design: Unlike HL7 v2’s rigid message structures, FHIR utilizes a resource-based approach. This allows for flexible data exchange, where specific resources representing relevant healthcare entities (patients, medications, observations) can be exchanged independently.
  • Modern Formats: FHIR leverages JSON and XML, familiar formats widely used in web technologies. This simplifies integration with existing healthcare systems and the development of FHIR-based applications.
  • Reduced Complexity: Compared to the complex configuration requirements of HL7 v2, FHIR offers a more user-friendly approach, reducing development time and implementation costs.

2. Interoperability and Data Sharing:

  • Standardized Data Model: FHIR builds upon a well-defined data model, ensuring consistent representation of healthcare concepts across different systems. This eliminates the need for complex data translations and fosters seamless data exchange.
  • RESTful API: FHIR utilizes a RESTful API, a standardized method for accessing and exchanging data over the web. This facilitates integration with modern healthcare systems, mobile devices, and web applications, breaking down communication barriers between disparate platforms.
  • Enhanced Data Sharing: By simplifying data exchange and ensuring interoperability, FHIR promotes collaboration between healthcare providers. This allows for a more holistic view of patient information, leading to better-coordinated care and improved patient outcomes.

3. Enabling Innovation and Improved Patient Care:

  • Rich Resource Library: FHIR offers a vast and ever-growing library of resources encompassing a wide range of healthcare data. This enables developers to build innovative applications that address specific healthcare needs.
  • Real-World Applications: FHIR powers various applications like patient portals, telehealth platforms, and clinical decision support systems. These applications enhance patient engagement, improve accessibility to care, and empower healthcare providers with data-driven insights.
  • Future-Proof Standard: With its flexible architecture and active development, FHIR is well-positioned to accommodate the evolving needs of healthcare data exchange. This ensures continued innovation and fosters the development of cutting-edge healthcare solutions.

There are existing integrators for HL7 and FHIR standards as well as numerous other standards available in the healthcare industry. One of the prominent integrator examples is Iguana which provides data connections for CCD, X12, JSON, and others besides the HL7 and FHIR.

On one hand, such integrators are great because they provide a way to connect to any data source and in any format. On the other hand, they are very expensive and using such an integrator doesn’t take care of the main challenge: communicating with hospitals, settling organizational moments, and setting up the processes.

To tackle these challenges, we came up with a product for our client, which is a custom-developed utilization review system that can be integrated with EMRs using HL7 v2 and FHIR standards.

Real-world FHIR success stories

CareOregon, a health plan provider, implemented FHIR to empower patients. By leveraging FHIR’s data exchange capabilities, CareOregon created a secure patient portal. This portal allows patients to access their electronic health information from various providers, regardless of the healthcare system used. This not only improves transparency and patient engagement but also fosters a sense of ownership over their health data.

The world-renowned Mayo Clinic demonstrates the power of FHIR for improved care delivery. By integrating data from various clinical systems through FHIR, Mayo Clinic has achieved a more comprehensive view of patient data. This holistic view allows healthcare providers to make better-informed decisions, personalize treatment plans, and ultimately, deliver superior patient care.

Epic App Showroom and Cerner Code Composer app marketplaces utilize FHIR APIs to integrate third-party applications seamlessly with Epic and Cerner EHR systems, enhancing functionality and data exchange. In our upcoming article, we’ll talk about our experience in creating such applications.

The Future is FHIR, But the Choice is Yours

While HL7 v2 has served the healthcare industry well, the future of data exchange lies in the flexibility and ease of use offered by FHIR. Its standardized approach and modern technology promote seamless communication and empower innovative healthcare solutions.

Now comes the critical decision: leverage existing FHIR integrators or embark on custom development.

Existing Solutions:

Pre-built FHIR integrators like Iguana offer a faster and potentially more cost-effective route. These solutions are designed for interoperability and often come with pre-configured features and technical support. However, they might not cater to every specific need, and customization options might be limited.

Custom Development:

Developing a custom solution allows for complete control and tailoring to your specific requirements. This can be ideal for organizations with unique workflows or data needs. However, custom development requires significant investment in time, resources, and ongoing maintenance.

The Choice:

The best option hinges on your priorities. Consider factors like budget, timeline, in-house technical expertise, and the level of customization required.

Carefully evaluate your needs and explore both options through demos or consultations. Existing solutions like Iguana can provide valuable insights and potentially address your core requirements. On the other hand, custom development might be the better choice for highly specialized needs.

Remember, the road to successful interoperability starts with understanding your specific goals and choosing the approach that best empowers your healthcare organization to deliver exceptional patient care.

Book a call with our experts

Feel free to drop us a message regarding your project – we’re eagerly looking forward to hearing from you!