One of the challenges with reading and understanding how CDA templates link together in PCC is that we are continuing to create new content templates, and have several still in Public Comment or Trial Implementation state. This means that we have document, section and entry content templates in several different published documents instead of neatly wrapped up in a single technical framework document. A single technical framework document (volume 2) is the end goal, but we must eat this elephant one bite at a time and deal with the complexities that come with such a task. Basically templates can be documented in one of 3 places: PCC Technical Framework Volume 2 (hereafter referred to as PCC-TF–2), CDA Content Modules Supplement, or profile supplements to the PCC-TF–2. Where templates are documented depends on their current state in the IHE development and publication process: Public Comment, Trial Implementation or Final Text. So yes, it is a bit confusing to navigate at first, but once you understand the makeup it is actually fairly straightforward. First let us cover these 3 locations, then we will talk about specifics of the types of templates and where each might be found.
PCC Technical Framework Volume 2
This contains all templates that are in Final Text state. That is, those templates that have been released into production. It is certainly possible that document templates in profile supplements may reference templates here.
CDA Content Modules Supplement
This is a holding tank for section and entry templates that are in the Public Comment or Trial Implementation state. PCC created this document several years ago to accomodate the need to share templates in draft state (Public Comment or Trial Implementation) across and between various profile supplements. At the time we had a lot of duplication across profile supplements and it quickly became very complicated to manage so this was a nice change. As it turned out this also became a great tool for other IHE domains to use as well. The QRPH domain has several templates in this same published document.
New IHE profiles are written initially as supplements to the Final Text version of the technical framework. This was intentionally designed in this way so that profiles must go through a period of implementation and testing to determine if they are ready to be released into the wild, which in IHE is defined as Final Text. More information on the process can be found on the IHE wiki. Getting back to the topic at hand, only document content templates will be found in profile supplements. Those document templates will reference section and/or entry templates that will be found in either the PCC-TF–2 or CDA Content Modules. So now that you understand a bit about where templates can be found here is a quick breakdown of the different types of templates that are found in these locations.
Document templates contain a list of section (and sometimes entry) templates and are identified by a name and a LOINC code. Document templates may be found in either the PCC-TF–2 or in profile supplements.
Section templates may contain other sections or entries, or both. These templates may be found in either the PCC-TF–2 or the CDA Content Modules Supplement, however are typically not found in profile supplements.
Entry templates are essentially the same as Section templates, in that they may be found in PCC-TF–2 or CDA Content Modules, but typically not in profile supplements.
In summary consider the matrix below that shows where each type of template may be found. Note the the PCC-TF–2 is the only location where all three are found, and this makes sense as the ultimate goal is to roll everything into the technical framework.
Finding a Template
To find a particular template of interest the best way is to look in the table of contents in the appropriate document, alternately one could search by name, or better yet by the template identifier. Every template in PCC (as well as other domains) is assigned a unique template identifier. The registry for these templates is available on the wiki, however these template identifiers also appear in the three document locations covered in this post (reference above matrix for which ones appear in which document). So while searching by name will get you most of the way there, searching by the unique template identifier is gaurenteed an exact match.
This revised approach of template management has certainly helped PCC (and QRPH) to manage the influx of new templates over the past several years, with the trade-off that finding the template you are looking for takes a bit of understanding of where to look. Hopefully this post fills in some of the gaps for folks who need it.