The detailed description of a substance, typically at a level beyond what is used for prescribing.

## Elements

| Name | Required | Type | Description |
| --- | --- | --- | --- |
| identifier |  | [Identifier](/content/docs/api/fhir/datatypes/identifier/index.html) | Identifier by which this substance is known<br>Details<br>Identifier by which this substance is known. |
| type |  | [CodeableConcept](/content/docs/api/fhir/datatypes/codeableconcept/index.html) | High level categorization, e.g. polymer or nucleic acid<br>Details<br>High level categorization, e.g. polymer or nucleic acid. |
| status |  | [CodeableConcept](/content/docs/api/fhir/datatypes/codeableconcept/index.html) | Status of substance within the catalogue e.g. approved<br>Details<br>Status of substance within the catalogue e.g. approved. |
| domain |  | [CodeableConcept](/content/docs/api/fhir/datatypes/codeableconcept/index.html) | If the substance applies to only human or veterinary use<br>Details<br>If the substance applies to only human or veterinary use. |
| description |  | string | Textual description of the substance<br>Details<br>Textual description of the substance. |
| source |  | Reference< [DocumentReference](/content/docs/api/fhir/resources/documentreference/index.html) >\[\] | Supporting literature<br>Details<br>Supporting literature. |
| comment |  | string | Textual comment about this record of a substance<br>Details<br>Textual comment about this record of a substance. |
| moiety |  | SubstanceSpecificationMoiety\[\] | Moiety, for structural modifications<br>Details<br>Moiety, for structural modifications. |
| id |  | string | Unique id for inter-element referencing<br>Details<br>Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces. |
| extension |  | [Extension](/content/docs/api/fhir/datatypes/extension/index.html)\[\] | Additional content defined by implementations<br>Details<br>May be used to represent additional information that is not part of the basic definition of the element. |
| modifierExtension |  | [Extension](/content/docs/api/fhir/datatypes/extension/index.html)\[\] | Extensions that cannot be ignored even if unrecognized<br>Details<br>May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. |
| role |  | [CodeableConcept](/content/docs/api/fhir/datatypes/codeableconcept/index.html) | Role that the moiety is playing<br>Details<br>Role that the moiety is playing. |
| identifier |  | [Identifier](/content/docs/api/fhir/datatypes/identifier/index.html) | Identifier by which this moiety substance is known<br>Details<br>Identifier by which this moiety substance is known. |
| name |  | string | Textual name for this moiety substance<br>Details<br>Textual name for this moiety substance. |
| stereochemistry |  | [CodeableConcept](/content/docs/api/fhir/datatypes/codeableconcept/index.html) | Stereochemistry type<br>Details<br>Stereochemistry type. |
| opticalActivity |  | [CodeableConcept](/content/docs/api/fhir/datatypes/codeableconcept/index.html) | Optical activity type<br>Details<br>Optical activity type. |
| molecularFormula |  | string | Molecular formula<br>Details<br>Molecular formula. |
| amount[x] |  | [Quantity](/content/docs/api/fhir/datatypes/quantity/index.html), string | Quantitative value for this moiety<br>Details<br>Quantitative value for this moiety. |
| property |  | SubstanceSpecificationProperty\[\] | General specifications for this substance, including how it is related to other substances<br>Details<br>General specifications for this substance, including how it is related to other substances. |
| id |  | string | Unique id for inter-element referencing<br>Details<br>Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces. |
| extension |  | [Extension](/content/docs/api/fhir/datatypes/extension/index.html)\[\] | Additional content defined by implementations<br>Details<br>May be used to represent additional information that is not part of the basic definition of the element. |
| modifierExtension |  | [Extension](/content/docs/api/fhir/datatypes/extension/index.html)\[\] | Extensions that cannot be ignored even if unrecognized<br>Details<br>May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. |
| molecularWeight |  | SubstanceSpecificationStructureMolecularWeight | The molecular weight or weight range (for proteins, polymers or nucleic acids)<br>Details<br>The molecular weight or weight range (for proteins, polymers or nucleic acids). |
| source |  | Reference< [DocumentReference](/content/docs/api/fhir/resources/documentreference/index.html) >\[\] | Supporting literature<br>Details<br>Supporting literature. |
| representation |  | SubstanceSpecificationStructureRepresentation\[\] | Molecular structural representation<br>Details<br>Molecular structural representation. |

## Search Parameters

| Name | Type | Description | Expression |
| --- | --- | --- | --- |
| code | token | The specific code | SubstanceSpecification.code.code |

## Inherited Elements

| Name | Required | Type | Description |
| --- | --- | --- | --- |
| id |  | string | Logical id of this artifact<br>Details<br>The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.  |
| meta |  | [Meta](/content/docs/api/fhir/datatypes/meta/index.html) | Metadata about the resource<br>Details<br>The metadata about the resource. |
| implicitRules |  | uri | A set of rules under which this content was created<br>Details<br>A reference to a set of rules that were followed when the resource was constructed. |
| language |  | code | Language of the resource content<br>Details<br>The base language in which the resource is written. |
| text |  | [Narrative](/content/docs/api/fhir/datatypes/narrative/index.html) | Text summary of the resource, for human interpretation<br>Details<br>A human-readable narrative that contains a summary of the resource. |
| contained |  | Resource\[\] | Contained, inline Resources<br>Details<br>These resources do not have an independent existence apart from the resource that contains them. |
| extension |  | [Extension](/content/docs/api/fhir/datatypes/extension/index.html)\[\] | Additional content defined by implementations<br>Details<br>May be used to represent additional information that is not part of the basic definition of the resource. |
| modifierExtension |  | [Extension](/content/docs/api/fhir/datatypes/extension/index.html)\[\] | Extensions that cannot be ignored<br>Details<br>May be used to represent additional information that is not part of the basic definition of the resource. |

> **This resource is still undergoing development and review by the appropriate Workgroups. At this time, it is considered only a draft resource not suitable for production implementation**