CCD, CDA, C-CDA: What's in a name?

The healthcare industry is infamous for its aggressive use of acronyms that often confuse people more than they help. Chief among these confusing acronyms is CCD, CDA, and C-CDA. Though similar in both name and function, these terms don't always mean the same thing.

Luckily, our resident HL7 Whisperer, Nick Hatt, is here to help you decipher what these terms mean, what they don't, and how they relate to each other when it comes to sharing patient data with EHRs.

Is every CCD a CDA?

No. CCD stands for Continuity of Care Document, and it has origins as a paper document.

If I say "CCD" to someone at Redox, what will they think I mean?

We would think you are referring to a CDA document.

What's a CDA?

A CDA is an electronic document written in the HL7 Clinical Document Architecture.

Is every C-CDA a CDA?

Yes. C-CDA is set of rules for CDAs to follow so that they are easy to exchange.

Is every CDA a C-CDA?

No. C-CDA is an implementation guide. It sets very specific rules about how to use CDA. C-CDA originated around the 2010/Meaningful Use timeframe, and CDA is about 10 years older than that.

Is every C-CDA a CCD?

No. C-CDA spells out many different documents including CCD, but also Progress Note, Diagnostic Imaging Report, and Discharge Summary. Each of those has different rules for what it should include.

Are there CCDs that aren't C-CDAs?

Yes. There have been many iterations of the CCD concept, most notably C32, which was the de-facto standard before C-CDA was published.

What's in CCD and why does it keep changing?

Medications, Problems, Allergies, and Results are the required sections in C-CDA version 1.1, but there are many more optional pieces.

Social History and Vital Signs are added to the required information for C-CDA version 2.1.

The C-CDA specification evolves to fit new use cases and also meet federal standards like USCDI.

Wait, there are versions?

Yes, but most people only care about C-CDA v2.1 because it's written into federal rules.

Does FHIR replace CDA?

For some use cases, yes. But CDA is the backbone of networks like Carequality and TEFCA. Those networks are exploring ways to use FHIR to exchange data, but CDA will be here for a long time. 

If you only want to deal with FHIR (I don’t blame you!) Redox can convert CDA to FHIR and FHIR back to CDA.

Does FHIR replace CCD?

It can, but there need to be rules put in place, just like with C-CDA. Think C-FHIR. The closest equivalent to C-CDA is the US Core Implementation Guide. 

What is USCDI? 

USCDI is a standardized set of data elements and terminologies intended to make interoperability more successful. It’s not coupled to a particular data model like FHIR or CDA so it can be implemented by both. Newer versions of C-CDA will align with newer versions of USCDI. 

If you have any questions about these terms (or anything else healthcare related), feel free to reach out—we're happy to clarify.

This blog post is an updated version of the original, which was published in March 2017.