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How Health Data Standards Support Healthcare Interoperability

Adopting health data standards in a consistent and comprehensive manner will be key to enabling meaningful healthcare interoperability.

Achieving true healthcare interoperability across the care continuum is a top priority for providers, payers, and other key industry stakeholders.

Seamless, comprehensive data sharing is particularly important for healthcare organizations looking to earn incentive payments through the CMS Promoting Interoperability (PI) Program, formerly known as meaningful use.

The adoption and use of health data standards forms the basis for enabling interoperability across organizations and between EHR systems.

According to ONC, “standards are agreed-upon methods for connecting systems together. Standards may pertain to security, data transport, data format or structure, or the meanings of codes or terms.”

In the healthcare industry, several different standards development organizations (SDOs) create, define, update, and maintain health data standards through collaborative processes that involve health IT users.

While SDOs have created several well-known standards intended to promote interoperability, lack of widespread adoption and use lessen the effectiveness of existing standards. In addition, differences in the way developers implement data standards can slow progress toward achieving healthcare interoperability.

Why is interoperability such a complex challenge for vendors and healthcare organizations, and how can health data standards help achieve the goals of a connected care ecosystem?


According to HIMSS, interoperability is “the ability of different information systems, devices and applications (systems) to access, exchange, integrate and cooperatively use data in a coordinated manner, within and across organizational, regional and national boundaries, to provide timely and seamless portability of information and optimize the health of individuals and populations globally.”

There are four levels of interoperability: foundational, structural, semantic, and organizational.

Foundational interoperability

Foundational interoperability is the ability of one IT system to send data to another IT system. The receiving IT system does not necessarily need to be able to interpret the exchanged data — it must simply be able to acknowledge receipt of the data payload.

Structural interoperability

Structural interoperability represents the ability of the recipient system to interpret information at the data field level.

Semantic Interoperability

Semantic interoperability is the ability of health IT systems to exchange and interpret information and actively use the information exchanged.

Achieving semantic interoperability allows providers to exchange patient summary information with other caregivers and authorized parties using different EHR systems to improve care quality, safety, and efficiency.

This level of interoperability allows healthcare organizations to seamlessly share patient information to reduce duplicative testing, enable better-informed clinical decision-making, and avoid adverse health events. Effective health data exchange can also help to improve care coordination, reduce hospital readmissions, and ultimately save hospitals money.  

Organizational Interoperability

According to HIMMS, organizational interoperability includes “governance, policy, social, legal, and organizational considerations to facilitate the secure, seamless and timely communication and use of data both within and between organizations, entities, and individuals.”

While organizational interoperability is the goal, most healthcare organizations are still working to establish foundational and structural interoperability.

Hospitals and health systems can utilize existing health data standards to achieve lower levels of interoperability and set a solid foundation for future improvements in health data exchange.


Standards offer health IT developers, EHR vendors, and healthcare organizations the means to ensure health IT systems and devices can exchange data successfully.

ONC is currently responsible for curating the set of standards and implementation specifications developed by independent industry groups such as Health Level 7 International (HL7) and DirectTrust.

The federal agency’s Interoperability Standards Advisory (ISA) recognizes several standards for different aspects of health data exchange and interoperability.

ONC recently released the 2022 ISA Reference Guide to include standards improvements based on recommendations from stakeholders and subject matter experts.

Three industry standards support foundational and structural interoperability.

Consolidated-Clinical Document Architecture (C-CDA)

C-CDA was developed by HL7, Integrating the Healthcare Environment (IHE), the Health Story Project, and ONC. C-CDA creates clinical documents that contain both human-readable text and machine-readable Extensible Markup Language (XML), according to ONC.

According to HL7, C-CDA offers users a library of templates and prescribes their use for specific document types. 

The standard provides a single source of clinical document architecture (CDA) templates for twelve structured document types and one unstructured document type. CDA is a document markup standard that specifies the structure and semantics of clinical documents for data exchange. Health IT developers, health information exchanges (HIEs), immunization registries, SDOs, EHR vendors, and healthcare organizations use C-CDAs to share information.

Healthcare providers use C-CDAs to send continuity of care documents, consultation notes, diagnostic imaging reports, discharge summaries, and other documents to enable well-informed clinical decision-making.

The 2015 Edition health IT certification final rule includes certification criteria related to the implementation, usability, and quality of C-CDAs.

Direct secure messaging

Direct messaging allows providers to send and receive health information over the internet securely. DirectTrust, a collaborative, non-profit industry alliance, supports health data exchange using the direct message standard. Like C-CDA, Direct is a form of document-based exchange.

DirectTrust built direct exchange using specifications and protocols called the Direct standard. An ONC-sponsored public-private collaboration called the Direct Project developed the Direct standard in 2010.

Since DirectTrust began tracking transactions in 2014, the organization has facilitated nearly 2.9 billion direct secure messages, an average of more than 79 million transactions per month.

DirectTrust has also created a security and trust framework that supports provider-to-provider Direct exchange and bidirectional data exchange between patients and providers. The network includes over 291,000 healthcare organizations.

Fast Healthcare Interoperability Resources (FHIR)

FHIR is an internet-based data standard developed and maintained by HL7 that connects different discrete data elements.

Data elements, or resources, are assigned standardized, shareable identifiers that function like the URL of a webpage. Resources can include metadata, text, or particular data elements, enabling discrete data sharing rather than document-based exchange.

FHIR has very quickly become one of the most popular standards for enabling structural – and in some cases semantic – interoperability.  Most major EHR vendors have invested in the standard, which has helped publicize the approach and cement FHIR as a leading method for data exchange.

FHIR, in conjunction with standardized application programming interfaces (APIs), allows developers to create apps that can plug into EHR systems and deliver information directly into the provider workflow.

The ONC final rule calls medical providers and health IT developers to encourage patient data access using FHIR-based APIs and third-party apps.

ONC initially proposed to adopt the HL7 FHIR standard as a foundational standard and requested comment on four options to determine the best version of FHIR to adopt. Finally, ONC adopted FHIR Release 4. The 2015 edition health IT certification criteria updates and the new standardized API functionality dates are required by December 31, 2022.


In a recent Healthcare Strategies podcast episode, Kristian Feterik, medical director of interoperability at the University of Pittsburgh Medical Center (UPMC), noted that while FHIR is a simple concept, variation in adoption creates challenges for interoperability.

“It is a transport layer. Basically, the key concepts in FHIR are modular and they have an interconnecting structure,” Feterik said. “However, what happens is that there are often guidelines—not so much standards—that are set.”

For example, he noted that there are 10 to 50 properties for each FHIR resource, such as patient demographic information or medication orders. However, EHR vendors select only some of those resource properties instead of making all of them required, which ultimately hinders data-sharing efforts.

“If we are to achieve better interoperability, we really would need to agree upon the required properties or attributes of a resource so that when those properties are missing, we could establish a better way to exchange information,” Feterik emphasized.


Healthcare organizations can take the following steps to improve their level of standardization for more complete health data exchange between health systems, healthcare organizations, medical practices, and other facilities.

Consider adopting 2015 Edition Certified EHR Technology

Organizations that use 2015 Edition Certified EHR Technology (CEHRT) have access to functionality to improve interoperability.

To achieve 2015 Edition ONC health IT certification, EHR vendors must ensure their product offerings meet all 2015 Edition health IT certification criteria and the 2015 Edition base EHR definition.

Certified health IT that fulfills the 2015 Edition base EHR definition must facilitate health data exchange and access through enhanced data export capabilities.

Systems must also include functionality that supports care transitions and allows third parties to connect to health IT products through an API.

Additionally, two 2015 Edition certification criteria require that health IT include the capabilities to promote the consistency and usability of C-CDAs.

The transitions of care certification criterion requires that health IT systems allow users to display only the data within a particular C-CDA section and set a preference for the display order of specific sections.

Health IT that fulfills these criteria allows users to adjust C-CDA display to improve usability and reduce information overload for providers who may be overwhelmed by the abundance of data available in C-CDAs.

Furthermore, 2015 Edition certified EHRs must include functionality that supports Direct exchange.

Participate in standards development processes

Stakeholders can submit feedback to ISA and weigh in on interoperability standards and implementation specifications.

ISA includes standards used to promote interoperability in public health, health research, patient care delivery, and administrative tasks in healthcare.  These standards are updated regularly in an effort to meet the interoperability needs of a broad range of organizations.

To ensure that industry input is a core component of the decision-making process, the agency holds annual public comment periods that allow providers, developers, and other interested parties to contribute their ideas to the standards community.

ISA aims to provide the industry with a single, public list of the standards and implementation specifications that best address clinical interoperability needs.

Additionally, ISA addresses the security limitations of data standards and implementation specifications and offers best practices to improve security.

By contributing to the national conversation surrounding healthcare interoperability standards, healthcare organizations can make sure SDOs consider the provider perspective.

As organizations move closer to the goal of universal semantic interoperability, communication between healthcare organization leadership, providers, EHR vendors, and federal entities will be vital for creating a meaningful data exchange environment that supports the delivery of high-quality care.

Next Steps

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