Characterizes potential impact of the condition on life, durable physiological function, or quality of life. May include concepts such as self-resolving, life-threatening, requires hospitalization, or potential loss of function or capacity. Different from severity in that a moderate subarachnoid hemorrhage is likely to be highly critical, whereas a moderate headache is not as important.

What is the value set for this?

unique id for the element within a resource (for internal references).

An Extension

Source of the definition for the extension code - a logical name or a URL.

The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition should be version specific. This will ideally be the URI for the Resource Profile defining the extension, with the code for the extension after a #.

Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).