The last thing I want to do here is to spark another debate around the so-called “failure” of HL7 version 3, instead, I want to provide some points of views to those who have not had exposure to anything beyond HL7 version 2.
So first, as I understand the debate, the blanket criticism around “HL7 version 3”, is largely around the HL7 version 3 messages. Often in the same sentence around HL7 version 3 also seems to suggest the success of CDA, Clinical Document Architecture, more specifically CDA level 3.
For those who have been around the block [HL7] for long enough, it’s pretty easy and straight forward to understand what is meant by this. However, increasingly, I speak to people are just starting to get themselves acquainted to the realm of HL7 version 3, CDA, RIM, et al, some of the recent debates has created a confusion I am hoping to shed some light.
Perhaps one of the things to highlight is that HL7 version 3 isn’t just messaging as you have in the world of HL7 version 3. It might be worth looking into some of the Foundation and Infrastructure components of HL7 version 3 that includes things like the Reference Information Model (RIM).
I also recently found it interesting that some of the newbies around CDA didn’t realize that CDA and v3 are related:
“CDA is based on the RIM (..), uses the V3 datatypes and methodology. The core of the CDA R2 body for machine processing (semantic interoperability) is the “clinical statement” model which is used across V3.” (Source: HL7)
“XML tags on their own do not have the precision required for clinical system interoperability. For example, does <provider> mean a person or an organization? Is it the person who created the document, signed it or performed some service? The XML tags in a CDA document are defined by the HL7 Reference Information Model (RIM) which is based on a variant of Unified Modeling Language (UML) and has been developed by literally hundreds of thousands of hours of collaborative work by practitioners, informaticists, vendors and implementers over the past decade. Each release of CDA is based on the version of the RIM current at the time of the ballot. The CDA specification details the relationship of the documents to the model and contains a refined model (RMIM) which takes RIM classes and further constrains them to define the precise parameters of a clinical document.” (Source: HL7)
With that background, the key question I ask, how is to do you actually work with CDA that’s meaningful for use for specific intentions? Surprisingly, I see some of the newbies haven’t had the opportunity to understand the overall background to design by constraint or the overall Health Level 7 Development Framework (HDF).
Take CCD for example, which uses the framework and methodology of HL7 with CDA as the baseline to constrain for specific use, which is further constrained by ONC for the US. “The Continuity of Care Document (CCD®) is a CDA® implementation of the continuity of care record (CCR), created by the American Society for Testing and Materials (ASTM). Disparate information systems can employ the CCD to exchange clinical summaries that contain key data about individual patients, such as diagnoses, medications, and allergies.” (Source: HL7)
Given the inter-relationship and dependencies, such claims perhaps need to more specific in nature to avoid confusion.