- USCDI sets the standard for what data gets shared
- HL7, FHIR, and C-CDA define how data moves
- HTI rules drive compliance and accountability
- Interoperability supports better care and coordination
If you work in health tech and feel overwhelmed by the blizzard of acronyms – FHIR, C-CDA, USCDI, HTI – you’re not alone.
Interoperability is one of the most critical (and complex) aspects of healthcare. These acronyms represent more than technical standards; they reflect a nationwide push to ensure health data is accessible, actionable, and aligned with both clinical and operational needs.
Let’s unpack how these standards and policies connect – and why they matter.
A new era for health data: Standards that work together
As care becomes more distributed across providers, patients, payers, public health, health tech, and life sciences, we need shared rules and tools to ensure data can travel with the patient.
The United States Core Data for Interoperability (USCDI) is at the center of that effort. Think of USCDI as the “what” of interoperability: it defines the essential data elements – like medications, allergies, lab results, and social determinants of health (SDOH) – that must be exchanged across certified health IT systems.
Each version of USCDI expands and refines this dataset:
- USCDI v3 is required by the finalized Health Data, Technology and Interoperability Rule 1 (HTI-1) rule by January 2026.
- USCDI v4 is proposed under Health Data, Technology and Interoperability Rule 2 (HTI-2.x), which aims to cover even more ground, including public health reporting and payer workflows. Systems are required to meet these requirements by January 2028.
The “How”: HL7 standards powering interoperability
To exchange data, we need more than just agreement on what to share – we need standardized ways to share it. That’s where Health Level Seven (HL7) comes in.
HL7 is the global standards development organization behind two key frameworks:
- HL7 v2.x (Health Level Seven Version 2.x): The backbone of clinical data exchange since 2011 with messaging standards that enable real-time interoperability across health systems. While v3 faltered due to cost and complexity, v2.x remains essential infrastructure – bridging legacy workflows and supporting the shift toward modern standards like FHIR amid growing regulatory momentum from USCDI.
- FHIR (Fast Healthcare Interoperability Resources): An API-based standard that supports real-time, structured data exchange. It powers apps, patient portals, and EHR integrations.
- C-CDA (Consolidated Clinical Document Architecture): A document-based standard used for sharing summaries like referrals or discharge notes that is ideal for transitions of care.
All these formats can carry USCDI-representative data, which is required under federal certification. They are not competing technologies but complementary tools, each suited for distinct kinds of data exchange.
Who’s in charge? ONC, ASTP, HTI Rules, and CMS
The Office of the National Coordinator (ONC) has long been the federal hub for health IT policy, but in July 2024, it was reorganized under the new Assistant Secretary for Technology Policy. This change, part of a broader HHS reorganization, reflects the growing urgency to align interoperability, AI, and data strategy nationally. As healthcare becomes increasingly digital, ASTP/ONC’s Health Data, Technology, and Interoperability (HTI) rules are the operational levers shaping how health IT must perform.
Here’s how that’s playing out:
- HTI-1 (Final, 2023): Requires certified EHRs to support FHIR APIs and USCDI v3, primarily focused on individual access and basic interoperability.
- HTI-2 (Proposed, 2024): Expands requirements to include public health, payers, and prior authorization workflows, introduces USCDI v4, and tightens information blocking rules.
Meanwhile, the Centers for Medicare & Medicaid Services (CMS) enforces these requirements through payment and participation incentives. For organizations in value-based care contracts, ensuring your data submissions to CMS meet compliance standards is essential for reimbursement.
|
HL7 (Who) Global Standards Org who created FHIR * C-CDA |
|
|---|---|
| HTI Rules (ASTP) | |
HTI-1
|
HTI-2 (proposed)
|
|
HL7 Interoperability tools Both can carry USCDI data |
|
FHIR API
|
C-CDA
|
|
USCDI V3/V4 (What) Standard health data – allergies, meds, SDOH, etc. |
|
Why interoperability matters: From mandate to mission
Interoperability rules aren’t just boxes to check. They represent a shift toward patient-centered, data-driven care. See how they impact the healthcare ecosystem below:
- Providers: Streamline referrals, reduce documentation, and enable faster access to external records
- Patients: Experience fewer gaps in care and more connected digital health tools
- Payers: Automate workflows, reduce friction, and support value-based care reporting
- Public health: Accelerate data collection and improve emergency response capabilities
- Health tech: Build smarter, scalable solutions that integrate across care settings
- Life sciences: Harness clinical-grade data to advance research and real-world evidence
The standards are here – make the data count
Standards like USCDI, FHIR, and C-CDA form the foundation of interoperability, while HTI rules provide regulatory weight. But real transformation happens when organizations work with a partner that keeps clinical terminology and code sets accurate, current, and aligned with evolving standards. Non-compliance can come at a steep cost, with information-blocking penalties reaching up to $1M per instance.
That’s where IMO Health comes in. We power major EHRs with clinically vetted terminology, simplify data maintenance, and help you stay ahead of regulatory demands. From supporting USCDI adoption to improving data quality across care settings, we turn compliance challenges into operational clarity.
At IMO Health, we believe the future of healthcare depends on high-quality, interoperable data. Let’s move past checkboxes and build smarter, more connected systems that work better for everyone.
| Component | Role |
|---|---|
| USCDI (United States Core Data for Interoperability) | Defines the minimum set of health data elements that must be exchanged (e.g., meds, allergies, social needs). HTI-1 uses v3, HTI-2 proposes v4. |
| FHIR (Fast Healthcare Interoperability Resources) | An API-based standard developed by HL7 for structuring and exchanging health data in real time (used by apps, portals, etc.). |
| C-CDA (Consolidated Clinical Document Architecture) | A document-based standard developed by HL7, widely used for sharing summary records (e.g., discharge summaries, referrals). |
| HTI-1 (Health Data, Technology, and Interoperability Rule 1) | A final rule by ONC (2023) that mandates certified health IT must support FHIR APIs and USCDI v3 for patient access and interoperability. |
| HTI-2 (Health Data, Technology, and Interoperability Rule 2) | A proposed rule (2024) expanding requirements to public health systems, payers, and electronic prior authorization, and moves to USCDI v4. Also updates information blocking rules. |
| HL7 (Health Level Seven International) | A nonprofit standards development organization that creates interoperability standards like FHIR and C-CDA. Works closely with the ASTP and stakeholders. |
| ONC (Office of the National Coordinator for Health Information Technology) | The federal agency within HHS that develops policies and certification criteria to support nationwide health IT interoperability. As of 2024, ONC is part of ASTP. |
| ASTP (Assistant Secretary for Technology Policy) | Leads HHS-wide strategy for data, technology, interoperability, and AI. Oversees agencies like ONC to align programs and investments that advance the HHS mission. Includes leadership from the HHS CTO, Chief Data Officer, and Chief AI Officer. |
| HL7 v2.x (Health Level Seven Version 2.x) | A lightweight messaging standard enabling real-time exchange of clinical data between systems – still widely used for labs, ADT feeds, and billing due to its simplicity and broad adoption. |
