Out of hospital care spans longer periods of time than in Acute and Ambulatory settings of care. Where a patient may have a 1 hour check up with their PCP - a Home Health nurse may be seeing that same patient at the same time for months. Within these extended periods of time that make up a Post-Acute admission, there are sub units of time already defined and driven by payer requirements, regulation, or internal processes that organize updates and changes to care being provided. For example - at the start of a Home Health admission, the patient may be coming off of an acute event and have care plans, and other clinical considerations to meet that need; whereas at the end of the admission (several weeks later) the patient may have rehabilitated and the care plan, meds, diagnosis, and other key clinical data points may have changed significantly. Currently there is no FHIR structure to build out these sub-units of a broader home health admission to properly define the progression of care. This project has been under discussion with the PACIO Project for several months. We have selected the Encounter Resource for our profile, and have begun the conversation with the broader PACIO group around field usages and requirements. Contributors to this discussion include providers, health IT organizations, other FHIR workgroups, and governing bodies like CMS. LOINC and others.