An occurrence of information being transmitted; e.g. an alert that was sent to a responsible provider, a public health agency that was notified about a reportable condition.

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 human-readable narrative that contains a summary of the resource and can be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

An Extension

• value @ url

An Extension

An Extension

• value @ url

Indicates the event was not performed, or did not occur for a specified reason.

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

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 SHALL be a URI for the Structure Definition defining the extension.

Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

Business identifiers assigned to this communication by the performer or other systems which remain constant as the resource is updated and propagates from server to server.

Allows identification of the communication as it is known by various participating systems and in a way that remains consistent across servers.

This is a business identifier, not a resource identifier (see discussion). It is best practice for the identifier to only appear on a single resource instance, however business practices may occasionally dictate that multiple resource instances with the same identifier can exist - possibly even with different resource types. For example, multiple Patient and a Person resource instance might share the same social insurance number.

The URL pointing to a FHIR-defined protocol, guideline, orderset or other definition that is adhered to in whole or in part by this Communication.

The URL pointing to an externally maintained protocol, guideline, orderset or other definition that is adhered to in whole or in part by this Communication.

This might be an HTML page, PDF, etc. or could just be a non-resolvable URI identifier.

An order, proposal or plan fulfilled in whole or in part by this Communication.

This must point to some sort of a 'Request' resource, such as CarePlan, CommunicationRequest, ServiceRequest, MedicationRequest, etc.

Part of this action.

Prior communication that this communication is in response to.

The status of the transmission.

This element is labeled as a modifier because the status contains the codes aborted and entered-in-error that mark the communication as not currently valid.

Captures the reason for the current state of the Communication.

This is generally only used for "exception" statuses such as "not-done", "suspended" or "aborted". The reason for performing the event at all is captured in reasonCode, not here.

The type of message conveyed such as alert, notification, reminder, instruction, etc.

There may be multiple axes of categorization and one communication may serve multiple purposes.

Characterizes how quickly the planned or in progress communication must be addressed. Includes concepts such as stat, urgent, routine.

Used to prioritize workflow (such as which communication to read first) when the communication is planned or in progress.

A channel that was used for this communication (e.g. email, fax).

The patient or group that was the focus of this communication.

Description of the purpose/content, similar to a subject line in an email.

Communication.topic.text can be used without any codings.

Other resources that pertain to this communication and to which this communication should be associated.

Don't use Communication.about element when a more specific element exists, such as basedOn or reasonReference.

The Encounter during which this Communication was created or to which the creation of this record is tightly associated.

This will typically be the encounter the event occurred within, but some activities may be initiated prior to or after the official completion of an encounter but still be tied to the context of the encounter.

The time when this communication was sent.

The time when this communication arrived at the destination.

The entity (e.g. person, organization, clinical information system, care team or device) which was the target of the communication. If receipts need to be tracked by an individual, a separate resource instance will need to be created for each recipient. Multiple recipient communications are intended where either receipts are not tracked (e.g. a mass mail-out) or a receipt is captured in aggregate (all emails confirmed received by a particular time).

The entity (e.g. person, organization, clinical information system, or device) which was the source of the communication.

The reason or justification for the communication.

Textual reasons can be captured using reasonCode.text.

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

A reference to a code defined by a terminology system.

Allows for alternative encodings within a code system, and translations to other code systems.

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

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

A logical reference (e.g. a reference to ValueSet.url) that identifies the value set/version that identifies the set of possible coded values this coding was chosen from or constrained by.

If this extension is used with an extensible binding, and the concept comes from outside the bound valueset, the value set SHALL be different from the bound valueset.

The identification of the code system that defines the meaning of the symbol in the code.

Need to be unambiguous about the source of the definition of the symbol.

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should reference to some definition that establishes the system clearly and unambiguously.

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured, and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Need to refer to a particular code in the system.

A representation of the meaning of the code in the system, following the rules of the system.

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Very often the text is the same as a displayName of one of the codings.

Indicates another resource whose existence justifies this communication.

Text, attachment(s), or resource(s) that was communicated to the recipient.

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 communicated content (or for multi-part communications, one portion of the communication).

Additional notes or commentary about the communication by the sender, receiver or other interested parties.