Activity Definition
An activity definition is a reusable, facility-scoped template for a clinical activity — a lab test, an imaging study, a counselling session — holding every default needed to order it. A facility defines the activity once, then turns it into a real order for a specific patient with a single "apply" action.
What it represents
In Care's FHIR-aligned model, an activity definition maps to the ActivityDefinition resource: a reusable description of an action to perform, defined independently of any patient.
The key distinction is that an activity definition is a blueprint, not a record of anything that happened. It carries the defaults — the procedure code, the specimens to collect, the observations to result, the locations and charges — but no patient. It belongs to a facility's catalog of services; the actual work for a patient lives in the service request it generates. Define "Complete Blood Count" once and apply it to twenty patients, and you get twenty separate orders, all sharing the same template.
Classification
Every activity definition carries one classification describing the nature of the work:
| Classification | Typical use |
|---|---|
laboratory | Blood panels, cultures, and other lab investigations |
imaging | X-ray, ultrasound, CT, and similar studies |
counselling | Structured counselling or advisory sessions |
surgical_procedure | Operative and bedside procedures |
education | Patient education and instruction activities |
How it connects
An activity definition is the assembly point that wires a facility's reusable pieces together, so a single order carries everything it needs without anyone reassembling it by hand:
- What to collect and measure — specimen definitions and observation definitions
- Where it happens — the locations and healthcare service the activity runs under
- What it costs — charge item definitions, so applying the activity can raise the right billing lines automatically
Patient and encounter are supplied at apply time, never stored on the template. The definition is applied against an encounter, which binds the result to a specific patient. Applying merges the stored defaults with that encounter context to produce a draft service request — plus a charge item for each linked charge, tied back to the same request.
Lifecycle
draft → active → retired
- draft — being authored, not yet ready for routine use
- active — published and available to apply to encounters
- retired — withdrawn from use but kept for history and reference
A separate unknown status covers definitions whose state cannot be determined. Activity definitions are also versioned: editing a definition appends a new version to a chain rather than overwriting it, with one marked as the latest. Older order templates stay referenceable even after the catalog moves on.
Permissions
Access is governed at the facility level — whether a role can author the catalog or only read from it and apply.
| Permission | Description | System Roles |
|---|---|---|
can_write_activity_definition | Create and edit activity definitions on a facility | Facility Admin, Admin |
can_read_activity_definition | List and view activity definitions on a facility | Facility Admin, Administrator, Admin, Staff, Doctor, Nurse, Volunteer |
Roles are granted through a user's organization and facility memberships, and cascade down the organization tree — a role held higher up applies to the facilities and resources beneath it.
Related
- Reference: Activity Definition (technical)
- Concept: Service Request
- Concept: Specimen Definition
- Concept: Observation Definition
- Concept: Charge Item Definition
- Concept: Encounter