Semantic scope of a code

The EMS project is creating a section for “injury event description.” We have been given a trial use code for this section. We are also interested in leveraging what we can from existing specifications in the interest of interoperability. We think that specializing the CCDA “history of present illness” section template would be good way to indicate that our injury section is a subtype of theirs. However, their section has its own LOINC code: if we specialize their template, we still use their code. So we can write a template that makes its relationship to the CCDA template explicit, or we can have a LOINC code that is specific to our semantics, but we can’t do both. What are the criteria for determining which way to go?

(If the answer is “an injury isn’t an illness: these are different,” we have several other sections and questions that face the same underlying issue.)

From LOINC’s perspective, I think it is probably your choice. (Not sure what HL7 SDWG would say). The LOINC code is meant to identify the expected information contents of that item. LOINC’s definition of HPI (which could be improved) is based on the general use of the phrase in medicine…which employs a broad definition of “illness” that would include trauma. In the context of trauma, an HPI might include things like the mechanism of injury, timing of the injury, situational details (entrapment, airbag deployment, etc), other prehospital assessments,etc (per The trauma manual: trauma and acute care surgery). So, I think it would be reasonable to use the HPI template if it fits your needs. The advantage of using an injury-specific code would be that you could find it much more easily amidst all the other HPI’s.