What is Clinical Document Architecture (CDA)?
Clinical Document Architecture (CDA) is a popular, flexible markup standard developed by Health Level Seven International (HL7). CDA defines the structure of certain medical records, such as discharge summaries and progress notes, as a way to better exchange this information between providers and patients. These documents can include text, images and other types of multimedia that are all integral parts of electronic health records (EHRs).
Together with the Continuity of Care Record (CCR) standard, CDA forms the basis for the Continuity of Care Document (CCD) standard for patient document information exchange. Both the CCR and CCD standards meet the U.S. government's guidelines for the meaningful use of EHR technology.
How does CDA work?
CDA is based on Extensible Markup Language (XML). To represent health concepts, CDA uses HL7's Reference Information Model (RIM), which puts data in a clinical or administrative context and expresses how pieces of data are connected. CDA also takes advantage of coding systems such as Systematized Nomenclature of Medicine -- Clinical Terms and Logical Observation Identifiers Names and Codes.
With the HL7 format using XML and RIM, Clinical Document Architecture enables EHRs and other health IT systems to process documents while also letting people easily read them on web browsers and mobile devices.
By setting standards for information and document exchange, CDA is a step toward the goal of ensuring that any EHR software system can create and read patient records. Many EHR vendors can produce CDA from their proprietary formats, according to HL7.
CDA doesn't identify a particular method for transferring the data in a document; options include Digital Imaging and Communications in Medicine, Multi-Purpose Internet Mail Extensions, File Transfer Protocol and Hypertext Transfer Protocol, as well as HL7 version 2 messages and HL7 version 3 messages. HL7 version 2 paired with CDA health data standards is used by most health information exchanges.
What is in a CDA document?
A CDA document typically includes the following elements:
- Header. This part contains metadata such as patient information, healthcare providers and document type.
- Clinical data. This element includes data types, such as vital signs and decision-support details.
- Data exchange information. This encodes data in a standardized way so it can be shared among different systems and healthcare providers.
- Semantics. This ensures the meaning of clinical data is preserved across systems.
- Schema. This element keeps the format and content of the document intact when transferred between carriers.
- Validation. This ensures adherence to HL7 standards and correct formatting.
6 characteristics of CDA
CDA is among the most widely adopted HL7 standards. It uses a common design structure with the following six characteristics, as set forth by HL7:
- Persistence. It remains in use for a long period.
- Stewardship. It's maintained by a trusted organization, such as a hospital.
- Potential for authentication. Authentication is legal attestation that the clinical information is accurate.
- Context. This provides a default context to the record, such as the patient identity and who created the document.
- Wholeness. The full document, not just parts of it, can be authenticated.
- Human readability. A person can read the material on a browser or mobile device.
Benefits of CDA
CDA offers several benefits to healthcare providers and patients. The most important advantages include the following capabilities and functionality:
- Interoperability. This allows seamless exchange of clinical information across different healthcare systems.
- Standardization. This provides a consistent schema and encoding format, reducing errors and improving clarity.
- Use cases. These include clinical decision support, public health reporting and unstructured data integration.
- Scalability. CDA is adaptable and scalable between various healthcare settings, from small clinics to large hospital networks.
CDA vs. CCD
CDA and CCD are closely linked but serve distinct purposes. CDA is a flexible framework that outlines the form and semantic structure of clinical documents for interoperability. It's a core component of the HL7 standards.
On the other hand, CCD is a specific implementation of the CDA standard focused on the exchange of patient summary information. It combines the clinical document framework with specific templates to streamline data exchange, especially in healthcare transitions and referrals.
While CDA provides the foundation for structuring clinical documents, CCD is a targeted application of this framework, optimized for specific use cases like continuity of care.
What is the Fast Healthcare Interoperability Resources standard?
FHIR is an HL7 standard designed to complement and, in some cases, replace older standards like CDA. FHIR builds on the strengths of the CDA while leveraging modern web technologies for improved flexibility and ease of implementation.
FHIR focuses on resource-based data exchange, allowing for smaller, discrete data elements to be shared. This approach contrasts with CDA's document-centric model, providing greater agility for developers and healthcare systems.
FHIR can exchange information about finances and other areas not directly linked to patient care. It can also share information such as genomic data at accelerated speed. In 2024, the Centers for Medicare and Medicaid Services released the Interoperability and Prior Authorization Final Rule, also known as the CMS-0057-F regulation. It requires payers to use HL7 FHIR APIs to exchange data among healthcare providers and other payers.
Although FHIR is gaining traction in the healthcare industry, CDA remains valuable for use cases requiring complete, structured documents. These include legal medical records and detailed clinical summaries.
HL7 FHIR APIs are driving healthcare innovation. Learn more about how this is happening.
