A homogeneous material with a definite composition.

Unique identifier for the substance.

This identifier is associated with the kind of substance in contrast to the Substance.instance.identifier which is associated with the package/container.

A code that classifies the the general type of substance. This is used for searching, sorting and display purposes.

The level of granularity is defined by the category concepts in the value set. More fine-grained filtering can be performed using the metadata and/or terminology hierarchy in Substance.code.

A code (or set of codes) that identify this substance.

This could be a reference to an externally defined code. It could also be a locally assigned code (e.g. a formulary), optionally with translations to the standard drug codes.

A description of the substance - its appearance, handling requirements, and other usage notes.

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

Identifier associated with the package/container (usually a label affixed directly).

When the substance is no longer valid to use. For some substances, a single arbitrary date is used for expiry.

The amount of the substance.

A substance can be composed of other substances.

The amount of the ingredient in the substance - a concentration ratio.

Another substance that is a component of this substance.