The organization Health Level 7 (HL7) has been the brand for international standards in healthcare since 1987. Its product HL7 Version 2 (V2) is the most commonly used standard for data exchange in hospitals worldwide. However, from a technological standpoint, V2 is unmistakably a child of the 1980s. Version 3, the successor version that was adopted as normative in 2005, has not really found favor with the industry thus far. Only the Clinical Document Architecture (CDA) element of Version 3 has managed to gain a foothold.
The reasons for Version 2’s persistent success: Implementation is simple and cost-effective, and it can easily be “tweaked” to meet individual requirements. However, this is often done at the expense of quality and interoperability. The reason for Version 3’s failure: Implementation is complicated and therefore expensive. Since interfaces are regarded as a “necessary evil” by some manufacturers, their willingness to accept high costs for interface implementation is correspondingly low.
However, intervening developments in hardware technology (tablets rather than desktops), network architecture (clouds rather than LANs), and software design (flexible apps rather than static software) have brought V2 to its technological limits. For some time now, the magic formula for modern integration in other industries has been “open API,” i.e. a well-documented programming interface with clearly defined content and functions.
Applying this model for success to healthcare is the basic idea behind FHIR, the fourth generation of HL7 standards. FHIR (short for Fast Healthcare Interoperability Resources and pronounced “fire”) focuses on quick implementation with good output quality and the flexibility for modification to meet national, domain-specific, and individual requirements. FHIR uses the following basic principles to achieve this goal:
Reusing established technologies
FHIR is based on a series of widely used and thoroughly tested web standards, such as XML/JSON for serialization, HTTP/REST with TLS encryption for transport, and OAuth2 for authorization and authentication. This enables manufacturers to draw on a large pool of qualified developers. Libraries and tools available in countless programming languages shorten development cycles and increase software quality.
Rigorous validation and support for extensions
FHIR resources (data objects) are subject to rigorous validation, which ensures full compliance with the standard during implementation to minimize the risk of errors and incompatibilities as much as possible. Nevertheless, FHIR provides mechanisms that allow easier modification of resources to meet individual needs. Open registries facilitate the publication and reuse of these “extensions.”
Openness and community
FHIR is license-free, so there are no restrictions on access to the specification or to the groups that develop FHIR. Developers can find advice and support in an international forum, and a publicly accessible change request system makes the specification process interactive and transparent. Thousands of developers worldwide have now embraced FHIR, and they engage in a lively exchange of knowledge, ideas, code samples and open source tools. HL7 holds Connectathons several times a year to ensure that the standard keeps up with the rigorous demands of implementers and users.
FHIR is still at the “Standards for Trial Use” stage at present, but the core specification will become normative this year. Numerous firms, including ICW, are already implementing FHIR interfaces. The SMART on FHIR framework defines how third-party applications can be integrated into primary systems and holds the greatest appeal for manufacturers of hospital information systems because they can flexibly expand their own systems’ features by seamlessly integrating web apps. This makes interoperability a solid business case. Starting in 2018, implementation of this framework will be mandatory for HIS manufacturers in the USA as part of the “meaningful use” subsidy program. IHE has now published numerous profiles (e.g. for document exchange, alerts, or medication administration) based on FHIR. Industry giants like Apple, Google, Samsung, and Microsoft have become regular presences at the annual FHIR Developer Days. Countries like Canada, the United Kingdom, the Netherlands, Chile, and Australia are currently developing national infrastructures based on FHIR. In Germany, “MedikationsplanPlus” will become the first FHIR use case on a national scale.
FHIR at Klingon → www.qhul.org