A container for a collection of resources.

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

The base language in which the resource is written.

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

A persistent identifier for the bundle that won't change as a bundle is copied from server to server.

Persistent identity generally only matters for batches of type Document, Message, and Collection. It would not normally be populated for search and history results and servers ignore Bundle.identifier when processing batches and transactions. For Documents the .identifier SHALL be populated such that the .identifier is globally unique.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

• value @ url

The purpose of this identifier.

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

Allows users to make use of identifiers when the identifier system is not known.

This element deals only with general categories of identifiers. It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage. Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

Establishes the namespace for the value - that is, a URL that describes a set values that are unique.

There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

Identifier.system is always case sensitive.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

Time period during which identifier is/was valid for use.

Organization that issued/manages the identifier.

The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.

Indicates the purpose of this bundle - how it is intended to be used.

It's possible to use a bundle for other purposes (e.g. a document can be accepted as a transaction). This is primarily defined so that there can be specific rules for some of the bundle types.

The date/time that the bundle was assembled - i.e. when the resources were placed in the bundle.

For many bundles, the timestamp is equal to .meta.lastUpdated, because they are not stored (e.g. search results). When a bundle is placed in a persistent store, .meta.lastUpdated will be usually be changed by the server. When the bundle is a message, a middleware agent altering the message (even if not stored) SHOULD update .meta.lastUpdated. .timestamp is used to track the original time of the Bundle, and SHOULD be populated.

Usage:

• document : the date the document was created. Note: the composition may predate the document, or be associated with multiple documents. The date of the composition - the authoring time - may be earlier than the document assembly time
• message : the date that the content of the message was assembled. This date is not changed by middleware engines unless they add additional data that changes the meaning of the time of the message
• history : the date that the history was assembled. This time would be used as the _since time to ask for subsequent updates
• searchset : the time that the search set was assembled. Note that different pages MAY have different timestamps but need not. Having different timestamps does not imply that subsequent pages will represent or include changes made since the initial query
• transaction | transaction-response | batch | batch-response | collection : no particular assigned meaning

The timestamp value should be greater than the lastUpdated and other timestamps in the resources in the bundle, and it should be equal or earlier than the .meta.lastUpdated on the Bundle itself.

If a set of search matches, this is the total number of entries of type 'match' across all pages in the search. It does not include search.mode = 'include' or 'outcome' entries and it does not provide a count of the number of entries in the Bundle.

Only used if the bundle is a search result set. The total does not include resources such as OperationOutcome and included resources, only the total number of matching resources.

A series of links that provide context to this bundle.

Both Bundle.link and Bundle.entry.link are defined to support providing additional context when Bundles are used (e.g. HATEOAS).

Bundle.entry.link corresponds to links found in the HTTP header if the resource in the entry was read directly.

This specification defines some specific uses of Bundle.link for searching and paging, but no specific uses for Bundle.entry.link, and no defined function in a transaction - the meaning is implementation specific.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

A name which details the functional use for this link - see http://www.iana.org/assignments/link-relations/link-relations.xhtml#link-relations-1.

The reference details for the link.

An entry in a bundle resource - will either contain a resource or information about a resource (transactions and history only).

• profile @ resource

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

A series of links that provide context to this entry.

The Absolute URL for the resource. The fullUrl SHALL NOT disagree with the id in the resource - i.e. if the fullUrl is not a urn:uuid, the URL shall be version-independent URL consistent with the Resource.id. The fullUrl is a version independent reference to the resource. The fullUrl element SHALL have a value except that:

• fullUrl can be empty on a POST (although it does not need to when specifying a temporary id for reference in the bundle)
• Results from operations might involve resources that are not identified.

fullUrl might not be unique in the context of a resource. Note that since FHIR resources do not need to be served through the FHIR API, the fullURL might be a URN or an absolute URL that does not end with the logical id of the resource (Resource.id). However, but if the fullUrl does look like a RESTful server URL (e.g. meets the regex, then the 'id' portion of the fullUrl SHALL end with the Resource.id.

Note that the fullUrl is not the same as the canonical URL - it's an absolute url for an endpoint serving the resource (these will happen to have the same value on the canonical server for the resource with the canonical URL).

The Resource for the entry. The purpose/meaning of the resource is determined by the Bundle.type.

Information about the search process that lead to the creation of this entry.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Why this entry is in the result set - whether it's included as a match or because of an _include requirement, or to convey information or warning information about the search process.

There is only one mode. In some corner cases, a resource may be included because it is both a match and an include. In these circumstances, 'match' takes precedence.

When searching, the server's search ranking score for the entry.

Servers are not required to return a ranking score. 1 is most relevant, and 0 is least relevant. Often, search results are sorted by score, but the client may specify a different sort order.

See Patient Match for the EMPI search which relates to this element.

Additional information about how this entry should be processed as part of a transaction or batch. For history, it shows how the entry was processed to create the version contained in the entry.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

In a transaction or batch, this is the HTTP action to be executed for this entry. In a history bundle, this indicates the HTTP action that occurred.

The URL for this entry, relative to the root (the address to which the request is posted).

E.g. for a Patient Create, the method would be "POST" and the URL would be "Patient". For a Patient Update, the method would be PUT and the URL would be "Patient/[id]".

If the ETag values match, return a 304 Not Modified status. See the API documentation for "Conditional Read".

Only perform the operation if the last updated date matches. See the API documentation for "Conditional Read".

Only perform the operation if the Etag value matches. For more information, see the API section "Managing Resource Contention".

Instruct the server not to perform the create if a specified resource already exists. For further information, see the API documentation for "Conditional Create". This is just the query portion of the URL - what follows the "?" (not including the "?").

Indicates the results of processing the corresponding 'request' entry in the batch or transaction being responded to or what the results of an operation where when returning history.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

The status code returned by processing this entry. The status SHALL start with a 3 digit HTTP code (e.g. 404) and may contain the standard HTTP description associated with the status code.

The location header created by processing this operation, populated if the operation returns a location.

The Etag for the resource, if the operation for the entry produced a versioned resource (see Resource Metadata and Versioning and Managing Resource Contention).

Etags match the Resource.meta.versionId. The ETag has to match the version id in the header if a resource is included.

The date/time that the resource was modified on the server.

This has to match the same time in the meta header (meta.lastUpdated) if a resource is included.

An OperationOutcome containing hints and warnings produced as part of processing this entry in a batch or transaction.

For a POST/PUT operation, this is the equivalent outcome that would be returned for prefer = operationoutcome - except that the resource is always returned whether or not the outcome is returned.

This outcome is not used for error responses in batch/transaction, only for hints and warnings. In a batch operation, the error will be in Bundle.entry.response, and for transaction, there will be a single OperationOutcome instead of a bundle in the case of an error.

An entry in a bundle resource - will either contain a resource or information about a resource (transactions and history only).

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

A series of links that provide context to this entry.

The Absolute URL for the resource. The fullUrl SHALL NOT disagree with the id in the resource - i.e. if the fullUrl is not a urn:uuid, the URL shall be version-independent URL consistent with the Resource.id. The fullUrl is a version independent reference to the resource. The fullUrl element SHALL have a value except that:

• fullUrl can be empty on a POST (although it does not need to when specifying a temporary id for reference in the bundle)
• Results from operations might involve resources that are not identified.

fullUrl might not be unique in the context of a resource. Note that since FHIR resources do not need to be served through the FHIR API, the fullURL might be a URN or an absolute URL that does not end with the logical id of the resource (Resource.id). However, but if the fullUrl does look like a RESTful server URL (e.g. meets the regex, then the 'id' portion of the fullUrl SHALL end with the Resource.id.

Note that the fullUrl is not the same as the canonical URL - it's an absolute url for an endpoint serving the resource (these will happen to have the same value on the canonical server for the resource with the canonical URL).

A set of healthcare-related information that is assembled together into a single logical package that provides a single coherent statement of meaning, establishes its own context and that has clinical attestation with regard to who is making the statement. A Composition defines the structure and narrative content necessary for a document. However, a Composition alone does not constitute a document. Rather, the Composition must be the first entry in a Bundle where Bundle.type=document, and any other resources referenced from Composition must be included as subsequent entries in the Bundle (for example Patient, Practitioner, Encounter, etc.).

While the focus of this specification is on patient-specific clinical statements, this resource can also apply to other healthcare-related statements such as study protocol designs, healthcare invoices and other activities that are not necessarily patient-specific or clinical.

Information about the search process that lead to the creation of this entry.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Why this entry is in the result set - whether it's included as a match or because of an _include requirement, or to convey information or warning information about the search process.

There is only one mode. In some corner cases, a resource may be included because it is both a match and an include. In these circumstances, 'match' takes precedence.

When searching, the server's search ranking score for the entry.

Servers are not required to return a ranking score. 1 is most relevant, and 0 is least relevant. Often, search results are sorted by score, but the client may specify a different sort order.

See Patient Match for the EMPI search which relates to this element.

Additional information about how this entry should be processed as part of a transaction or batch. For history, it shows how the entry was processed to create the version contained in the entry.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

In a transaction or batch, this is the HTTP action to be executed for this entry. In a history bundle, this indicates the HTTP action that occurred.

The URL for this entry, relative to the root (the address to which the request is posted).

E.g. for a Patient Create, the method would be "POST" and the URL would be "Patient". For a Patient Update, the method would be PUT and the URL would be "Patient/[id]".

If the ETag values match, return a 304 Not Modified status. See the API documentation for "Conditional Read".

Only perform the operation if the last updated date matches. See the API documentation for "Conditional Read".

Only perform the operation if the Etag value matches. For more information, see the API section "Managing Resource Contention".

Instruct the server not to perform the create if a specified resource already exists. For further information, see the API documentation for "Conditional Create". This is just the query portion of the URL - what follows the "?" (not including the "?").

Indicates the results of processing the corresponding 'request' entry in the batch or transaction being responded to or what the results of an operation where when returning history.

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

The status code returned by processing this entry. The status SHALL start with a 3 digit HTTP code (e.g. 404) and may contain the standard HTTP description associated with the status code.

The location header created by processing this operation, populated if the operation returns a location.

The Etag for the resource, if the operation for the entry produced a versioned resource (see Resource Metadata and Versioning and Managing Resource Contention).

Etags match the Resource.meta.versionId. The ETag has to match the version id in the header if a resource is included.

The date/time that the resource was modified on the server.

This has to match the same time in the meta header (meta.lastUpdated) if a resource is included.

An OperationOutcome containing hints and warnings produced as part of processing this entry in a batch or transaction.

For a POST/PUT operation, this is the equivalent outcome that would be returned for prefer = operationoutcome - except that the resource is always returned whether or not the outcome is returned.

This outcome is not used for error responses in batch/transaction, only for hints and warnings. In a batch operation, the error will be in Bundle.entry.response, and for transaction, there will be a single OperationOutcome instead of a bundle in the case of an error.

Digital Signature - base64 encoded. XML-DSig or a JWT.

A Signature holds an electronic representation of a signature and its supporting context in a FHIR accessible form. The signature may either be a cryptographic type (XML DigSig or a JWS), which is able to provide non-repudiation proof, or it may be a graphical image that represents a signature or a signature process. This element allows capturing signatures on documents, messages, transactions or even search responses, to support content-authentication, non-repudiation or other business cases. This is primarily relevant where the bundle may travel through multiple hops or via other mechanisms where HTTPS non-repudiation is insufficient.

The signature could be created by the "author" of the bundle or by the originating device. Requirements around inclusion of a signature, verification of signatures and treatment of signed/non-signed bundles is implementation-environment specific.