FHIR API Interoperability Relies on Standardized Endpoint Publication

Interoperability of Health Level Seven (HL7) Fast Healthcare Interoperability Resources (FHIR) application programming interfaces (APIs) requires health IT developers to publish FHIR endpoints, according to a HealthITBuzz blog post written by ONC officials Wes Barker, Vaishali Patel, and Jeff Smith.

The ONC 21st Century Cures Act Final Rule requires certain developers of certified health IT to provide their customer base with a certified FHIR API to support patient access to health information by December 31, 2022.

ONC officials noted that to ensure patients can access these certified APIs “without special effort,” the Cures Rule API Conditions and Maintenance of Certification requires that certified health IT developers publish “service base URLs” or “endpoints” for all customers in a machine-readable format at no charge.

“These electronic endpoints are the specific locations on the internet that make it possible for an app to know where to go to access health information on behalf of the users,” Barker, Patel, and Smith wrote.

To monitor FHIR API implementation, ONC developed the Lantern tool which consumes public endpoint data, tests the accessibility of these endpoints, and then reports capability information to a public-facing dashboard.

“Through Lantern, we found variability in the publication of public endpoint lists, which makes it difficult for Lantern and other potential users of endpoints to consume the information in a systematic manner,” they explained.

Through the development of the tool, ONC worked with health IT stakeholders to form consensus around a standard format to publish FHIR endpoint lists.

In May 2021, ONC recommended that health IT developers certifying to the new FHIR-based API certification criterion use the FHIR Endpoint resource to publish endpoint lists.

“The more health IT developers that follow this approach the more standardized and consistent the ingestion of endpoints can be, without the need for potential customizations to process individual lists,” the ONC officials emphasized.

They noted that while this recommendation helps add consistency across the community, more work needs to be done to support FHIR interoperability.

Through Lantern, ONC found that the current structure of the FHIR Endpoint resource allows for listing only one organization: the managing organization of the endpoint. However, the managing organization may represent one of many organizations that the endpoint services.

“Having all healthcare organizations serviced by the endpoint accessible and in a standardized format would go a long way in meeting the Cures Rule’s goals for using APIs without special effort,” Barker, Patel, and Smith wrote.

“App developers would be able to easily fetch these endpoints to build accurate and comprehensive endpoint lists to better aid users select from where they want to access electronic health information,” they added.

Standardized endpoint publication would also help simplify the Facilitated and Brokered FHIR Exchange models of Trusted Exchange Framework and Common Agreement (TEFCA), the officials said.

During a December 2021 workshop, ONC officials discussed approaches to ensuring all associated organizations serviced by an endpoint are included in published endpoint information.

“One approach discussed focused on publishing endpoint information in the FHIR Endpoint resource format and corresponding FHIR Organization resources be made publicly accessible outside the FHIR server’s authentication/security framework,” they wrote.

“This would allow a user to query a publicly accessible endpoint’s system for associated organizations and retrieve them in the standardized FHIR format already supported by the system,” the authors continued.

Workshop participants generally agreed that standardization of endpoint list publication would benefit both the health IT developers and the users of certified API technology.

“We will continue to support the community in refining the standard and related implementation guidance through Lantern,” the officials said. “We are encouraged by stakeholder interest and look to the health IT community to continue to make progress on making FHIR APIs usable without special effort.”