HL7’s FHIR at Scale Taskforce (FAST) is preparing the FAST Directory Implementation Guide (IG) for its Standard for Trial Use (STU2) ballot. Formally titled the National Directory of Healthcare Providers and Services (NDH) IG, it builds on STU1 and supports a more consistent way to represent healthcare organizations, providers, services, relationships, and the electronic endpoints used to exchange information through Fast Healthcare Interoperability Resources (FHIR) application programming interfaces (APIs).
Finding reliable information remains difficult when providers, health plans, and exchange partners maintain separate directories. Records may disagree about practice locations, specialties, network participation, whether clinicians accept new patients, and where systems can connect. In a 2018 Medicare Advantage directory review, the Centers for Medicare & Medicaid Services (CMS) found that almost 50% of reviewed provider-directory locations had at least one inaccuracy. These inconsistencies create avoidable work and uncertainty and make a shared approach to directory data and endpoint discovery increasingly important.
What STU2 Adds
STU2 is more than a routine update. Proposed changes sharpen the IG’s scope and improve its usefulness for implementers, including:
- Refined directory profiles, terminology, search expectations, and resource relationships to support more consistent data exchange.
- Mappings to the Da Vinci PDex Plan-Net IG to help payers and directory operators assess interoperability and data reuse.
- Updates to endpoint connection information and onboarding-related metadata to support practical discovery and implementation.
- A streamlined approach to extensions and out-of-scope features, reducing complexity while preserving relevant directory capabilities.
These changes reflect ballot preparation and ongoing reconciliation; the development build remains subject to revision.
Making Shared Directory Information More Trustworthy
The FAST Directory Implementation Guide describes how directory information can be represented and shared while allowing local directories to retain details needed by their programs and communities. Reliable data requires both technical conformance and verification. Is it well-formed and consistent with FHIR requirements? Has it been checked against an authoritative source, such as a state licensing board or the organization responsible for the record?
Source updates, attestations, verification history, and discrepancy reports can help organizations identify information that needs review. Participating directories can exchange corrected records through agreed update processes, helping reduce duplicative maintenance and making provider and end-point data more useful. Each organization remains responsible for its verification policies, review processes, and accountability.
“Directory interoperability is not just about finding a record. It is about knowing which organization or service that record represents, whether the information is current, and where to connect,” stated a FAST Directory Co-Lead.
Connecting Directory Discovery with FAST Capabilities
The FAST Directory IG supports discovery; other FAST initiatives address complementary requirements for trusted exchange:
- FAST Identity: Identity matching and trusted digital identity across organizations
- FAST Security: Scalable client registration, authentication, and authorization
- FAST Scalable Consent: Management and communication of consent preferences
- FAST Testing at Scale: Approaches to evaluate interoperability across participants and workflows
A directory listing alone does not grant permission to access patient data; organizations must also apply identity, security, consent, and operational policy controls.
Working Alongside Da Vinci Plan-Net
The Da Vinci Payer Data Exchange (PDex) Plan-Net IG supports standardized FHIR APIs for health plan provider and pharmacy networks. The FAST Directory IG addresses broader directory relationships and electronic endpoint discovery. STU2’s Plan-Net mappings help implementers connect these complementary efforts without treating the two IGs as interchangeable.
Supporting Public Programs and Communities
For CMS programs, states, Medicaid agencies, HIEs, and community organizations, the FAST Directory IG offers a common technical approach to representing and exchanging provider, service, and endpoint information. For example, states and rural health networks can use it to examine how clinics, hospitals, payers, and community partners identify each other and exchange updates.
The relevance is growing. CMS’s 2026 proposed rule CMS-0062-P includes an alternative proposal referencing conformance with the FAST Directory IG for specified endpoint reporting. This is a proposal, not a final requirement, and illustrates why practical implementation feedback matters now.
As FAST prepares STU2 for ballot, we invite payers, providers, government programs, directory operators, and exchange partners to review the proposed changes, comment during ballot, join FAST Directory working calls, and bring real-world use cases and testing feedback.
Learn More
FAST Directory development build: https://build.fhir.org/ig/HL7/fhir-us-ndh/
FAST Directory Public Calls – Every other Monday: 3:00 p.m. ET/2:00 p.m. CT – https://www.hl7.org/concalls/
Da Vinci PDex Plan-Net: https://hl7.org/fhir/us/davinci-pdex-plan-net/
FAST Accelerator and working group information: https://confluence.hl7.org/spaces/FAST/overview
CMS online provider directory review (2018): https://www.cms.gov/Medicare/Health-Plans/ManagedCareMarketing/Downloads/Provider_Directory_Review_Industry_Report_Round_3_11-28-2018.pd
