The Standard

The HL7® FHIR® at Scale Taskforce (FAST) and the CARIN Alliance are joining forces to deliver the next generation of interoperable digital identity for U.S. healthcare. Together, we are aligning FAST Identity STU 3 with the CARIN Digital Trust Framework so that patients, providers, payers, and the networks that connect them can rely on a single, consistent foundation of trust as the CMS Aligned Networks ecosystem comes online.

This is more than a technical collaboration. It is a strategic commitment by two of the most active organizations in U.S. health data exchange to ensure the trust layer beneath nationwide interoperability is open, interoperable, and ready for scale.

Why This Partnership, Why Now

The CMS Health Technology Ecosystem and the Aligned Networks Pledge have raised the bar for what “connected” means in healthcare in the United States. Twenty-one networks have already committed to meeting the CMS Interoperability Framework criteria — and every one of them needs a way to answer a deceptively simple question every time data moves: who is on the other end of this transaction, and can we trust them?

FAST has spent years building the scalable, FHIR-based infrastructure that answers that question — identity matching, certificate-based trust, federated directories, and computable consent. The CARIN Alliance has spent equal effort building the policy fabric that makes credentials portable across organizations. The CARIN Digital Identity Credential Policy, published in September 2025, defines an open trust framework that lets credentials issued by one Credential Service Provider be recognized and accepted by another — grounded in NIST SP 800-63 identity assurance levels, NIST 800-53 controls, and the RFC 3647 policy structure used by mature certificate ecosystems.

The opportunity before us is to wire these two efforts together — not in parallel, but as a single, coherent stack that the industry can adopt.

What We Are Building Together: FAST Identity STU 3

FAST Identity STU 2 was published in December 2025, delivering implementer-validated guidance for identity matching across organizational boundaries using FHIR Patient, Person, and RelatedPerson profiles, the FHIR $match operation, and the HL7 Person Identifier as a persistent, interoperable identifier for longitudinal correlation.

FAST Identity STU 3 picks up where STU 2 left off. Working hand in hand with the CARIN Alliance, we are extending the implementation guide so that:

• FHIR-based identity workflows are bound to externally accredited identity assurance, so that an IAL2 or IAL3 credential issued can be recognized and honored anywhere in the FAST ecosystem, without each relying party performing its own independent evaluation.
• Federated workflows align with Tiered OAuth, OpenID Federation, and identity broker patterns — the same building blocks CARIN identifies as foundational to cross-framework reciprocity.
• Identity resolution scales across consumers, providers, payers, and applications, so that participants can prove who they are once and be trusted everywhere a FAST-conformant network reaches.

The result is a clear, implementable path from verified human or organization all the way to FHIR data exchanged with the right party, under the right consent, on the right network.

How States Can Move From Fragmented Programs to Shared, Scalable Infrastructure Using FAST

The CMS Aligned Networks Pledge marks a clear inflection point in federal health IT policy. For the first time, Centers for Medicare & Medicaid Services (CMS) is not simply setting compliance requirements for individual programs—it is asking the healthcare ecosystem to operate as connected networks, capable of secure, real-time, standards-based data exchange across payers, providers, public health and patients.

For states, this shift is significant.

States are no longer just one participant among many. They are increasingly the anchor for trust, identity, consent and directory infrastructure that enable CMS-aligned networks to function at scale. Medicaid programs, state CIO offices and HIEs sit at the intersection of policy, operations and technology. The CMS Aligned Networks Pledge makes that role explicit.

This blog explains:

1. What the CMS Aligned Networks Pledge really changes for states
2. Why traditional, program-by-program approaches will not scale
3. How the  HL7® FHIR® at Scale Taskforce (FAST)  provides the infrastructure states can reuse across initiatives
4. How states can leverage existing systems and vendors without starting over

The CMS Aligned Networks Pledge: A Shift from Programs to Infrastructure

Historically, CMS initiatives have been implemented as discrete programs:

• A new reporting requirement
• A new API mandate
• A new exchange use case
• Trusted digital identity and patient matching
• Scalable security and partner onboarding
• Computable, portable consent
• Authoritative directories for endpoint discovery

The CMS Aligned Networks Pledge represents a different expectation.

CMS is signaling that future interoperability depends on shared infrastructure capabilities, including:

• Trusted digital identity and patient matching
• Scalable security and partner onboarding
• Computable, portable consent
• Authoritative directories for endpoint discovery

These are not features of a single application. They are ecosystem functions.

For states, this means success is no longer measured by whether a single system goes live, but by whether multiple programs can reuse the same trust and exchange foundations.

Those of us working across health policy, technology, and standards are reimagining a system where individuals experience better outcomes, lower costs, and greater trust in how their health information is used and shared.

At HL7® International, a global standards development organization with members and affiliates in more than 50 countries, we are meeting our challenge head-on through collaboration and innovation. The HL7® FHIR® at Scale Taskforce (FAST) Accelerator takes that mission further by tackling the hard problems of scalability: Identity, Security, Consent, and National Directory services. These components are the backbone that supports the CMS Health Tech Ecosystem and Aligned Networks Pledge.

Paired with the Da Vinci Project, which applies FHIR to payer–provider workflows like prior authorization, clinical data exchange, payer data exchange, and patient cost transparency. HL7 is aligning infrastructure with real-world use cases. Da Vinci has recognized the value of FAST standards by selecting FAST Security as part of their security recommendations in their core health record exchange (HRex) specifications, showing a convergency across the ecosystem.

Where Sequoia’s RCE Role Elevates the Work: TEFCA as the National Trust Layer

FAST isn’t building infrastructure in a vacuum. Its work aligns with the Trusted Exchange Framework and Common Agreement (TEFCA), led by The Sequoia Project as the Recognized Coordinating Entity (RCE) for ASTP/ONC. TEFCA is a national framework for the secure and trusted exchange of clinical data across networks.

The HL7® FHIR® at Scale Taskforce (FAST) continues to translate national interoperability policy into implementable, real-world infrastructure. This month marks several major milestones, including the opening of the FAST Consent Ballot, the official publication of FAST Identity STU 2 and FAST Security STU 2, and continued progress on FAST National Directory toward STU 2. This reinforces the growing momentum toward CMS-Aligned Networks powered by FAST. 

These advances demonstrate how standards, trust frameworks, directory infrastructure and testing at scale converge to support scalable, secure and interoperable data exchange across the healthcare ecosystem. 

FAST Consent Ballot: Advancing Scalable, Network-Ready Consent 

The FAST Consent Implementation Guide (Edition 1 – US Realm) has entered formal HL7 balloting, providing the industry with a practical, interoperable approach to consent management at scale. 

The guide is designed to support: 

• Computable and portable consent representations across organizational and network boundaries 

• Subscription-based workflows for consent updates and downstream disclosures 

• Alignment with FAST Identity, FAST Security, and FAST Directory infrastructure 

• Use cases spanning payer-to-payer exchange, provider workflows, HIEs, and consumer-mediated access 

The HL7 FHIR at Scale Taskforce (FAST) is going international! As part of our mission to accelerate FHIR adoption and interoperability around the globe, FAST is taking its work beyond the U.S. to engage with the international health IT community. 

For the first time ever, FAST will be hosting a dedicated track at the HL7 FHIR Connectathon in Madrid, featuring two of our most critical and widely applicable Implementation Guides (IGs): 

🔐 FAST Security - https://build.fhir.org/ig/HL7/fhir-udap-security-ig/branches/main/ 
🆔 FAST Identity - https://build.fhir.org/ig/HL7/fhir-identity-matching-ig/ 

While these IGs were originally developed under the U.S. ONC's efforts to advance FHIR adoption, their guidance is intentionally broad and applicable globally. In fact, we're in the process of transitioning them to universal realm status, and your international input is vital. 

Why Participate? 
🌍 Help shape these key IGs to meet global needs 
🧪 Test and validate implementation with FAST experts
📚 Attend deep-dive breakout sessions focused on Security and Identity
🚀 Prepare for the future – FAST Security is a required standard for TEFCA FHIR exchange starting January 1, 2026 in the U.S. 

In the realm of healthcare, accurately managing patient identities across various systems is pivotal. The FHIR at Scale Taskforce (FAST) has developed the Interoperable Digital Identity and Patient Matching implementation guide (FAST Identity IG) to address these challenges effectively. This blog delves into the nuances of this implementation guide and encourages participation in its continuous improvement. 

Exploring the FAST Identity Implementation Guide 

The FAST Identity IG aims to enhance the FHIR patient $match operation for use in cross-organizational workflows. It serves as a comprehensive set of best practices not only for transactions directly invoking $match but also for other healthcare transactions that require robust identity matching and management.