Substance.instance

Substance may be used to describe a kind of substance, or a specific package/container of the substance: an instance.

= Must Support, = Is Modifier, = QiCore defined extension

Field	Card.	Type	Description
identifier	0..1	Identifier	Identifier associated with the package/container (usually a label affixed directly).
expiry	0..1	DateTime	When the substance is no longer valid to use. For some substances, a single arbitrary date is used for expiry.
quantity	0..1	Quantity	The amount of the substance.