UsageContext 
Specifies clinical/business/etc metadata that can be used to retrieve, index and/or categorize an artifact. This metadata can either be specific to the applicable population (e.g., age category, DRG) or the specific context of care (e.g., venue, care setting, provider of care).
= Must Support, = Is Modifier, = QiCore defined extension
| Field | Card. | Type | Description |
|---|---|---|---|
| code | 1..1 | Code | A code that identifies the type of context being specified by this usage context. |
| value[x] | 1..1 | Concept | Quantity | Interval<Quantity> | A value that defines the context specified in this context of use. The interpretation of the value is defined by the code. |