US rules and regulations now require US Core. As US Core evolves, mCODE has had to re-evaluate the parent classes of certain profiles. For example, in US Core 5.0 there are now two profile on Condition instead of one, and involve different categories (Condition.category), and a new profile for clinical examination results. To maintain alignment, the parent profiles of KarnofskyPerformanceStatus  and  ECOGPerformanceStatus  were switched from Observation to the newly-introduced  US Core Observation Clinical Test Result Profile .  Another issue is that there is no US Core generic observation profile in 5.0. Observations that can in different circumstances derive from clinical examination, imaging, or laboratory results do not cleanly fall into any US Core profile's catchment. This is the case with CancerDiseaseStatus. In addition, certain profiles will not inherit from US Core, for example, those that come from the Genomics Reporting IG or do not fit a US Core profile. These will have to be explicitly waived by FMG.