In the world of healthcare data interoperability, two standards dominate the conversation — HL7 and FHIR. As digital transformation in healthcare accelerates, understanding the difference between HL7 and FHIR is essential for IT professionals, developers, and healthcare organizations.
This blog breaks down HL7 vs FHIR, highlights their key differences, and shows how both can be used together for efficient and scalable healthcare integration.
🔍 What is HL7?
HL7 (Health Level Seven) is a set of international standards for the exchange of electronic health information. The most commonly used version is HL7 v2, which facilitates real-time data sharing between hospital systems like EHRs, LIS, RIS, and billing platforms.
Key features of HL7 v2:
- Plain text, pipe-delimited message structure
- Widely adopted in hospitals and labs
- Supports clinical messaging like ADT, ORM, ORU, etc.
- Requires interface engines like Mirth Connect for routing and transformation
🆚 HL7 vs FHIR: Key Differences
| Feature | HL7 v2 | FHIR |
| Format | Pipe-delimited text | JSON / XML |
| Communication | Traditional interfaces (LLP, MLLP) | RESTful APIs |
| Structure | Rigid, custom extensions | Modular, flexible Resources |
| Developer-Friendly | Requires HL7 expertise | Easier with web development knowledge |
| Common Usage | Legacy hospital systems | Modern health apps, EHR APIs |
🔄 Can You Use HL7 and FHIR Together?
Absolutely! Many healthcare systems still rely on HL7 v2 for core operations, while FHIR is being adopted for newer use cases like patient-facing apps, analytics, and cloud integration.
Here’s how you can use HL7 and FHIR together in real-world healthcare integration projects:
- HL7 to FHIR Mapping: Use an integration engine like Mirth Connect to convert HL7 v2 messages into FHIR resources.
- Hybrid Workflows: Legacy systems send HL7 messages while modern apps consume FHIR APIs.
- Gradual Transition: Organizations can upgrade individual workflows (e.g., lab results or discharge summaries) to FHIR while retaining HL7 for others.
🛠 Tools for HL7 and FHIR Integration
To integrate both standards effectively, these tools and techniques can help:
- Mirth Connect: Ideal for transforming and routing HL7 and FHIR messages
- FHIR Converters: Tools that map HL7 segments to FHIR resources
- Custom APIs: Build REST endpoints that accept FHIR and translate to HL7 messages for backend systems
- Validation Tools: Ensure message format compliance using HL7 and FHIR validators
💡 Real-World Example
Scenario: A hospital wants to send lab results (HL7 ORU messages) to a mobile app that supports FHIR.
Solution:
- Mirth Connect receives HL7 ORU^R01 message.
- Channel transforms the HL7 message into a FHIR Observation resource.
- Sends the FHIR resource to the mobile app via a REST API.
This is a common hybrid approach that leverages HL7 interface with FHIR APIs to bridge old and new systems.
Final Thoughts
Understanding the difference between HL7 and FHIR isn’t about choosing one over the other — it’s about knowing how to use them together. While HL7 integration continues to support traditional systems, FHIR is paving the way for innovative, patient-centric healthcare applications.
Whether you’re transitioning to FHIR implementation or managing existing HL7 messaging, adopting a hybrid approach will future-proof your organization and ensure seamless healthcare interoperability.