What is FHIR?
Fast Healthcare Interoperability Resources (FHIR) is an interoperability standard created by HL7. FHIR utilizes a more modular approach to inter-system messaging than previous HL7 standards versions. These modules, termed "resources", allow implementations to be more flexible to changing system processes than the traditional HL7V2 or V3 standards. The initial version of FHIR was created in 2012 and has undergone multiple revisions to date. There is currently an implementation standard in the draft standard for trial use (DTSU) phase, and not yet fully approved. Balloting for the current DSTU is slated for April of 2015 with a projected release of DSTU 2 for July 2015.  Rather than using multi-element structured messages such at HL7v2, HL7v3, and CDA standards, FHIR uses application programming interfaces (APIs) to select specific elements vs. the entire message as in the older HL7 standards. These APIs utilize a "RESTful" architecture, designed for web applications. REST stands for Representational State Transfer which allows for exchange of resources on an as needed basis, typically communicated via widely used HTTP or HTTPS protocols.
FHIR is governed by three separate bodies within HL7. The FHIR Governance Board, appointed by the FHIR Technical Steering Committee, provides broad oversight of the standard. The FHIR Management Group, also appointed by the Technical Steering Committee, manages the day-to-day operations of the standard. Finally, the Modeling and Methodology Work Group handles the resource creation, guidelines, and best practices.
FHIR is HL7's answer to the call for a new interoperability standard that could more easily be used on mobile and cloud-based applications, and also speed the implementation process. These implementations can often be completed within a day or week, versus the traditional month- or year-long implementation timeline. FHIR is a needed update to HL7v2, but expected to be much less disruptive to workflows than HL7v3.
The specification is free and allows unrestricted use. FHIR uses the building blocks of HL7v2, HL7v3, and CDA while improving the ease of use and flexibility to alter implementations as needed. The RESTful architecture is applied to web services to allow for easy transfer of resources between systems, since they can be accessed through a uniform resource locator (URL). Due to this architecture, FHIR is well suited for mobile and cloud-based platforms.
The RESTful API architecture also allows for transfer of data between systems without requiring the receiving system to know the structure of the API itself. This simplifies the interface between systems. (3) Once called to the receiving system, these individual resources can be extended and adapted based on individual implementation needs.
The FHIR Code
From "Fundamental Principles of FHIR (aka The FHIR Code)".
- Prioritize implementation
- Provide a flexible framework for interoperability
- Keep complexity where it belongs
- Support but not mandate tight specifications
- Leverage open source development principles
- Free to use
- Supports multiple exchange paradigms/architectures
- Leverage common web technologies
- Forward and backward compatibility
- Tooling requirements are mainstream and minimal
Resources are classified as either clinical, administrative, or infrastructural. These resources were developed from HL7v2 and from HL7v3's Reference Information Model (RIM); as such they are intended to coexist with previous HL7 standards. Resources are accessed via web protocol calls to specific URLs, and represented using either XML or JSON format. Resources are exchanged and manipulated via PUT, GET, POST, and DELETE operations via individual APIs. Using these APIs, the resources can be queried by a receiving system or pushed from a host system.
FHIR resources have related profiles to specify their metadata, associated structures, and relevant extensions used in those structures. Resource metadata includes resource ID, version ID, last modified date, and other information. Metadata can contain tags linking a specific resource to a workflow event; these tags can be used to trigger events that initiate system interactions. Metadata also allows for resources to be searched efficiently. Resources can also be referenced by one another using resource links, allowing for connection of various data elements.
Individual resources are contained within one of three primary categories, then sub-classified within each category:
- Device Interactions
- Workflow Management
- Document Handling
FHIR enabled apps in use today
Sustainable Medical Applications, Reusable Technologies (SMART) is a collaboration between the Harvard Medical School and the Office of the National Coordinator for Health Information Technology (ONC). SMART sought to develop a platform for the rapid development of health applications that could run across multiple EHRs. They succeeded, and now a variety of apps are "SMART-enabled". The apps are used in clinical back-office settings, research, patient communication and patient facing applications.
FHIR is also gaining support in the U.K. Nearly ten apps have already been developed for use in various setting. Additionally, an alliance with the UK Renal Data Collaboration is planned.
- Review of Bender, D., & Sartipi, K. (2013, June). HL7 FHIR: An Agile and RESTful approach to healthcare information exchange. In 2013 IEEE 26th International Symposium on Computer-Based Medical Systems (CBMS) (pp. 326-331). IEEE.
- Review of Kasthurirathne, S., Mamlin, B., Kumara, H., Grieve, G., & Biondich, P. (2015). Enabling Better Interoperability for HealthCare: Lessons in Developing a Standards Based Application Programing Interface for Electronic Medical Record Systems. J Med Syst Journal of Medical Systems, 39(182).
- Review of Smits, M., Kramer, E., Harthoorn, M., & Cornet, R. (2015). A comparison of two Detailed Clinical Model representations: FHIR and CDA. European Journal for Biomedical Informatics, 11(2), 7-17.
- FHIR DTSU v. 1.1. (2014). Retrieved October 21, 2014 from http://www.hl7.org/implement/standards/fhir/index.html
- Mckenzie, L. (2013, May 13)Introduction to FHIR. Retrieved October 20, 2014 from http://gforge.hl7.org/svn/fhir/trunk/presentations/2013-05%20Tutorials/Introduction%20to%20FHIR.pptx
- What exactly is RESTful programming? (2013, Jan 16). Retrieved October 23, 2014 from http://stackoverflow.com/questions/671118/what-exactly-is-restful-programming
- HL7. (2014, Oct 22) FHIR Wiki. Retrieved October 23, 2014 from http://wiki.hl7.org/index.php?title=FHIR
- Fundamental Principles of FHIR. (16 Sept 2014, 20:28). Retrieved 6 Dec 2015 from http://wiki.hl7.org/index.php?title=Fundamental_Principles_of_FHIR&oldid=90696
- Raths, D. (2014). "Trend: standards development. Catching FHIR: A new HL7 draft standard may boost web services development in healthcare." Healthcare Inform 31(2): 13, 16.
- SMART. (2014). SMART-Enabled HIT. Accessed October 23, 2014 from http://smartplatforms.org/smart-enabled-hit/