Playing With FHIR

FHIR Background

HL7’s Fast Healthcare Interoperability Resources (FHIR) specification is a standard for the structure and exchange of healthcare information. FHIR provides a structured approach to express a broad range of common clinical concepts from Patient and Doctor to claim and clinical quality measure as a set of atomic “resources”. The standard is free to use. It leverages existing standards that fuel today’s web-based interoperability, such as JSON, HTTP, OAuth and RESTful APIs. HL7 relies on input from a broad range of stakeholders to establish and refine the standard which recently reached a milestone with publishing of v4.0.0, the first normative version of the standard. Additionally, CMS is embracing FHIR in the form of public-facing FHIR APIs (e.g. BlueButton 2.0, Data at the Point of Care) while promoting its use to support interoperability (see 21st Century Cures Act and related federal rules).

FHIR Connectathon 22

A small team from Bellese recently traveled to Atlanta for the HL7 FHIR Connectathon 22.  Every quarter HL7 hosts a FHIR “Connectathon”. The purpose of the a Connecthaton is to test emerging and draft positions of the FHIR standard by implementing and testing them in software. The efforts are divided into many tracks, each focused on a different segment of the FHIR spec or use case.

Connectathon 22 was just held over a weekend (9/14 & 15/19) in Atlanta with over 400 attendees and 30 tracks. Bellese attended and participated in the Clinical Reasoning Track (includes measure specification and computation). In this track our focus was to implement and thereby validate the not-yet-standardized $import function (see Bulk FHIR Standard) to support the use case where a provider or vendor submits bulk FHIR data in support of clinical quality measure calculation.

Our effort

The Bellese team built a flexible proxy server (available on Github) that accepted bulk FHIR data per the emerging standard then made the many individual API calls to another, existing FHIR server to store each element of the bulk data file. In support of this, we worked with other track members to build a flexible and high performance solution. Late Saturday afternoon a break-out session and follow-up discussion led to changes in the proposed standard.

Our solution was flexible enough to accommodate these changes with little to no code changes. The performance of the solution caused some pleasant problems in our testing. The $import draft standard includes specification of how the receiving server should communicate progress of the asynchronous process. While the solution supported this specification, our tests with a 25 MB data file could never prove that we adhered. The server routinely replied immediately and correctly indicated the $import was complete. The solution was so fast; it was never “in progress”.


It was exciting to be part of an international standards-making process that embraced the “fail fast” and “learn by doing” mantras. We’re looking forward to being part of future Connectathons as we work with CMS to modernize their systems.


Since this post was originally written, Bellese has continued to participate in the development and adoption of the FHIR standard. In February CMS sponsored the first ever “CMS FHIR Connectathon”. This free event hosted a capacity crowd focused on validating FHIR usage in 17 tracks. Bellese again participated in the Clinical Reasoning track where representatives from major EHR vendors collaborated with measure developers and implementers to submit clinical data, calculate measures and retrieve the results. This tight, direct feedback loop allowed the group to validate the implementation of 6 CMS quality measures recently developed in FHIR R4.

In May HL7 held its first virtual FHIR Connectathon, Connectathon 24, in response to the COVID-19 pandemic. Bellese participated in one of 20 tracks, the Clinical Reasoning track which focused on validating FHIR v4 CMS quality measures and improving tools that improve measure validation. We’re looking forward to contributing to this track in the upcoming FHIR Connectathon scheduled for September 2020.

Written by

Bill LakenanDirector of Innovation