This is a wonderful question. Right now, we only allow fully pre-coordinated Concepts that exist in SNOMED. The list is in the vocabulary CONCEPT table. If you want to combine Concepts, you have to put several records into the CONDITION table at the same day.
However, SNOMED is build in a multi-dimensional bases, and all pre-coordinated Concepts have a link to their components. So, “Fracture of femur” is linked to “Fracture” and to “Femur”. But not all combinations exist. So, we could do a couple of things:
- We create all combinations people need and SNOMED doesn’t have.
- We put three new fields into CONDITION_OCCURENCE: anatomical_site, pathology, cause
- We somehow allow different concepts to be combined. Theoretically we have the FACT_RELATIONSHIP table for that, but nobody uses it