A request to convey information; e.g. the CDS system proposes that an alert be sent to a responsible provider, the CDS system proposes that the public health agency be notified about a reportable condition.

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.

An Extension

Present on web CRs (medium=web). Set by the orchestrator at dispatch time. Read by web-functions to validate the bearer token on the POST that submits the QR.

Present on outbound CRs. Set by handleTaskDue at dispatch: deliveryTime + REMINDER_THRESHOLD_MINUTES (default 60). Updated by the sweeper in three scenarios: (1) bootstrap if absent (CR.meta.lastUpdated + threshold); (2) reset when the patient is active (last-inbound-message-timestamp + threshold); (3) advanced after a successful reminder send (last reminder completion + REMINDER_INTERVAL_MINUTES default 24h). Read only by the orchestrator sweeper; the sidecar never reads or writes this extension.

Present on outbound CRs after the first inbound reply. Set by the sidecar's stampLastActivity on every patient interaction (answer, constraint re-prompt, resume signal). Read by the orchestrator sweeper to reset the reminder schedule when the patient is active. Best-effort: a missed stamp means a reminder might fire one cycle early, which is self-correcting on the next interaction.

Present on web CRs. Set by the orchestrator at dispatch time. Read by the sidecar to embed in the WhatsApp invitation template payload so the patient can click through to the browser.

Present on reverse CRs. Set by the sidecar from the Meta webhook's from_user_id. Read by the orchestrator to resolve identity (scanSenderIdentities by BSUID). BSUID persists across phone-number changes.

Present on reverse CRs. Set by the sidecar from the Meta webhook's contacts.profile.name. Read by the orchestrator as a hint for identity resolution and as input to Patient.name when creating a new Patient.

Present on reverse CRs. Set by the sidecar from the Meta webhook's metadata.phone_number_id. Read by the orchestrator to upsert a stub Organization on the unresolved-receiver path.

Present on reverse CRs. Set by the sidecar. Read by the orchestrator to cache wa-phone-number-id onto the upserted stub Organization.

Present on reverse CRs. Set by the sidecar from the Meta webhook timestamp. Preserves the original event time across identity-resolution latency.

Present on reverse CRs. Set by the sidecar. Codes: no-match, multiple-matches, non-conversational-only, no-active-cr, unresolved-receiver. Read by the orchestrator to decide its response (create identity, refuse, walk Person.link, reattach, upsert stub Organization).

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it 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 is allowed to 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).

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.

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.

Present on reverse CRs for dedup. Set by the sidecar from the inbound sender's phone and/or BSUID. Used with If-None-Exist conditional create to prevent duplicate reverse CRs for the same sender.

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.

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

Outbound CRs: set to 'active' by handleTaskDue at dispatch; promoted to 'completed' by the sidecar when the QR finishes; revoked by the orchestrator sweeper when the deadline or reminder cap is reached. Reverse CRs: set to 'active' by the sidecar; promoted to 'completed' by the orchestrator on successful resolution; set to 'entered-in-error' on multiple-matches. Reminder CRs: set to 'active' by the sweeper; promoted to 'completed' by the sidecar after sending the template. Web CRs: set to 'active' by the orchestrator; promoted to 'completed' by web-functions on browser POST; revoked by the session sweeper on TTL expiry.

The status of the communication request.

Only set on reverse CRs (category=identity-resolution-required, written by the sidecar) and reminder CRs (category=reminder, written by the orchestrator sweeper). Absent on standard outbound CRs. Read by the Subscription criteria to route CRs to the correct queue.

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

Codes for general categories of communications such as alerts, instruction, etc.

If true indicates that the CommunicationRequest is asking for the specified action to not occur.

The attributes provided with the request qualify what is not to be done.

Always present. Set by handleTaskDue from COMMUNICATION_MEDIUM_CODE (default 'whatsapp'). The sidecar's cr-events Subscription filters on medium=whatsapp; web CRs are delivered via a separate path. Configurable via COMMUNICATION_MEDIUM_SYSTEM and COMMUNICATION_MEDIUM_CODE.

Codes for communication mediums such as phone, fax, email, in person, etc.

A reference to a code defined by a terminology system.

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.

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

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

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.

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

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.

Present on outbound CRs: set by handleTaskDue to Task.for. May be absent on reverse CRs where the identity is unresolved.

Outbound CRs: set by handleTaskDue to the originating Task reference. Reverse CRs: set by the sidecar to sender hint resources. Not indexed by HAPI (HAPI-0524); the Task↔CR link is carried on Task.output instead.

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

Outbound CRs: initial payload set by handleTaskDue to the Questionnaire reference (contentReference). The sidecar appends the QuestionnaireResponse reference once the QR is created (ensureCRPayloadCarriesQRRef). Reverse CRs: payload set by the sidecar to the inbound message text (contentString). The CR↔QR link lives here because QuestionnaireResponse.basedOn is NOT used (HAPI rejects non-CarePlan/ServiceRequest basedOn with HAPI-0931).

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).

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.

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.

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

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

CRUCIAL: QuestionnaireResponse.basedOn is NOT used (HAPI rejects non-CarePlan/ServiceRequest basedOn with HAPI-0931). The CR<->QR link lives on cr.payload[].contentReference.

The time when this communication is to occur.

Present on outbound CRs. Computed by buildDeliveryAnchoredPeriod: start = deliveryTime (when the CR was actually dispatched, not the scheduled time); end = deliveryTime + intended window length (restriction.period.end - restriction.period.start, or TASK_DEFAULT_RESPONSE_WINDOW_MINUTES default 24h). Absent on reminder CRs and reverse CRs. Read by the deadline sweeper to auto-revoke CRs past their response window.

occurrencePeriod.end = deliveryTime + intended-window-length (issue #157). Under queue backpressure, delivery time diverges from scheduled time; anchoring to delivery ensures every reached patient gets the full intended response window.

Outbound CRs: set by handleTaskDue to Task.for (resolved Reference). Reverse CRs: set by the sidecar to a resolved Reference when identity is known, or an identifier-only Reference (phone or BSUID system) when identity is unresolved. Read by the sidecar to address outbound WhatsApp messages.

Present on web CRs (medium=web). Set by the orchestrator at dispatch time. Read by web-functions to validate the bearer token on the POST that submits the QR.

Present on outbound CRs. Set by handleTaskDue at dispatch: deliveryTime + REMINDER_THRESHOLD_MINUTES (default 60). Updated by the sweeper in three scenarios: (1) bootstrap if absent (CR.meta.lastUpdated + threshold); (2) reset when the patient is active (last-inbound-message-timestamp + threshold); (3) advanced after a successful reminder send (last reminder completion + REMINDER_INTERVAL_MINUTES default 24h). Read only by the orchestrator sweeper; the sidecar never reads or writes this extension.

Present on outbound CRs after the first inbound reply. Set by the sidecar's stampLastActivity on every patient interaction (answer, constraint re-prompt, resume signal). Read by the orchestrator sweeper to reset the reminder schedule when the patient is active. Best-effort: a missed stamp means a reminder might fire one cycle early, which is self-correcting on the next interaction.

Present on web CRs. Set by the orchestrator at dispatch time. Read by the sidecar to embed in the WhatsApp invitation template payload so the patient can click through to the browser.

Present on reverse CRs. Set by the sidecar from the Meta webhook's from_user_id. Read by the orchestrator to resolve identity (scanSenderIdentities by BSUID). BSUID persists across phone-number changes.

Present on reverse CRs. Set by the sidecar from the Meta webhook's contacts.profile.name. Read by the orchestrator as a hint for identity resolution and as input to Patient.name when creating a new Patient.

Present on reverse CRs. Set by the sidecar from the Meta webhook's metadata.phone_number_id. Read by the orchestrator to upsert a stub Organization on the unresolved-receiver path.

Present on reverse CRs. Set by the sidecar. Read by the orchestrator to cache wa-phone-number-id onto the upserted stub Organization.

Present on reverse CRs. Set by the sidecar from the Meta webhook timestamp. Preserves the original event time across identity-resolution latency.

Present on reverse CRs. Set by the sidecar. Codes: no-match, multiple-matches, non-conversational-only, no-active-cr, unresolved-receiver. Read by the orchestrator to decide its response (create identity, refuse, walk Person.link, reattach, upsert stub Organization).

Present on reverse CRs for dedup. Set by the sidecar from the inbound sender's phone and/or BSUID. Used with If-None-Exist conditional create to prevent duplicate reverse CRs for the same sender.

Outbound CRs: set to 'active' by handleTaskDue at dispatch; promoted to 'completed' by the sidecar when the QR finishes; revoked by the orchestrator sweeper when the deadline or reminder cap is reached. Reverse CRs: set to 'active' by the sidecar; promoted to 'completed' by the orchestrator on successful resolution; set to 'entered-in-error' on multiple-matches. Reminder CRs: set to 'active' by the sweeper; promoted to 'completed' by the sidecar after sending the template. Web CRs: set to 'active' by the orchestrator; promoted to 'completed' by web-functions on browser POST; revoked by the session sweeper on TTL expiry.

Only set on reverse CRs (category=identity-resolution-required, written by the sidecar) and reminder CRs (category=reminder, written by the orchestrator sweeper). Absent on standard outbound CRs. Read by the Subscription criteria to route CRs to the correct queue.

Always present. Set by handleTaskDue from COMMUNICATION_MEDIUM_CODE (default 'whatsapp'). The sidecar's cr-events Subscription filters on medium=whatsapp; web CRs are delivered via a separate path. Configurable via COMMUNICATION_MEDIUM_SYSTEM and COMMUNICATION_MEDIUM_CODE.

Present on outbound CRs: set by handleTaskDue to Task.for. May be absent on reverse CRs where the identity is unresolved.

Outbound CRs: set by handleTaskDue to the originating Task reference. Reverse CRs: set by the sidecar to sender hint resources. Not indexed by HAPI (HAPI-0524); the Task↔CR link is carried on Task.output instead.

Outbound CRs: initial payload set by handleTaskDue to the Questionnaire reference (contentReference). The sidecar appends the QuestionnaireResponse reference once the QR is created (ensureCRPayloadCarriesQRRef). Reverse CRs: payload set by the sidecar to the inbound message text (contentString). The CR↔QR link lives here because QuestionnaireResponse.basedOn is NOT used (HAPI rejects non-CarePlan/ServiceRequest basedOn with HAPI-0931).

CRUCIAL: QuestionnaireResponse.basedOn is NOT used (HAPI rejects non-CarePlan/ServiceRequest basedOn with HAPI-0931). The CR<->QR link lives on cr.payload[].contentReference.

Present on outbound CRs. Computed by buildDeliveryAnchoredPeriod: start = deliveryTime (when the CR was actually dispatched, not the scheduled time); end = deliveryTime + intended window length (restriction.period.end - restriction.period.start, or TASK_DEFAULT_RESPONSE_WINDOW_MINUTES default 24h). Absent on reminder CRs and reverse CRs. Read by the deadline sweeper to auto-revoke CRs past their response window.

occurrencePeriod.end = deliveryTime + intended-window-length (issue #157). Under queue backpressure, delivery time diverges from scheduled time; anchoring to delivery ensures every reached patient gets the full intended response window.

Outbound CRs: set by handleTaskDue to Task.for (resolved Reference). Reverse CRs: set by the sidecar to a resolved Reference when identity is known, or an identifier-only Reference (phone or BSUID system) when identity is unresolved. Read by the sidecar to address outbound WhatsApp messages.

A request to convey information; e.g. the CDS system proposes that an alert be sent to a responsible provider, the CDS system proposes that the public health agency be 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 language.

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

Present on web CRs (medium=web). Set by the orchestrator at dispatch time. Read by web-functions to validate the bearer token on the POST that submits the QR.

Present on outbound CRs. Set by handleTaskDue at dispatch: deliveryTime + REMINDER_THRESHOLD_MINUTES (default 60). Updated by the sweeper in three scenarios: (1) bootstrap if absent (CR.meta.lastUpdated + threshold); (2) reset when the patient is active (last-inbound-message-timestamp + threshold); (3) advanced after a successful reminder send (last reminder completion + REMINDER_INTERVAL_MINUTES default 24h). Read only by the orchestrator sweeper; the sidecar never reads or writes this extension.

Present on outbound CRs after the first inbound reply. Set by the sidecar's stampLastActivity on every patient interaction (answer, constraint re-prompt, resume signal). Read by the orchestrator sweeper to reset the reminder schedule when the patient is active. Best-effort: a missed stamp means a reminder might fire one cycle early, which is self-correcting on the next interaction.

Present on web CRs. Set by the orchestrator at dispatch time. Read by the sidecar to embed in the WhatsApp invitation template payload so the patient can click through to the browser.

Present on reverse CRs. Set by the sidecar from the Meta webhook's from_user_id. Read by the orchestrator to resolve identity (scanSenderIdentities by BSUID). BSUID persists across phone-number changes.

Present on reverse CRs. Set by the sidecar from the Meta webhook's contacts.profile.name. Read by the orchestrator as a hint for identity resolution and as input to Patient.name when creating a new Patient.

Present on reverse CRs. Set by the sidecar from the Meta webhook's metadata.phone_number_id. Read by the orchestrator to upsert a stub Organization on the unresolved-receiver path.

Present on reverse CRs. Set by the sidecar. Read by the orchestrator to cache wa-phone-number-id onto the upserted stub Organization.

Present on reverse CRs. Set by the sidecar from the Meta webhook timestamp. Preserves the original event time across identity-resolution latency.

Present on reverse CRs. Set by the sidecar. Codes: no-match, multiple-matches, non-conversational-only, no-active-cr, unresolved-receiver. Read by the orchestrator to decide its response (create identity, refuse, walk Person.link, reattach, upsert stub Organization).

May be used to represent additional information that is not part of the basic definition of the resource and that modifies the understanding of the element that contains it 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 is allowed to 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).

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.

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.

Present on reverse CRs for dedup. Set by the sidecar from the inbound sender's phone and/or BSUID. Used with If-None-Exist conditional create to prevent duplicate reverse CRs for the same sender.

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.

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

A plan or proposal that is fulfilled in whole or in part by this request.

Allows tracing of authorization for the request and tracking whether proposals/recommendations were acted upon.

Completed or terminated request(s) whose function is taken by this new request.

The replacement could be because the initial request was immediately rejected (due to an issue) or because the previous request was completed, but the need for the action described by the request remains ongoing.

Allows tracing the continuation of a therapy or administrative process instantiated through multiple requests.

A shared identifier common to all requests that were authorized more or less simultaneously by a single author, representing the identifier of the requisition, prescription or similar form.

Requests are linked either by a "basedOn" relationship (i.e. one request is fulfilling another) or by having a common requisition. Requests that are part of the same requisition are generally treated independently from the perspective of changing their state or maintaining them after initial creation.

Outbound CRs: set to 'active' by handleTaskDue at dispatch; promoted to 'completed' by the sidecar when the QR finishes; revoked by the orchestrator sweeper when the deadline or reminder cap is reached. Reverse CRs: set to 'active' by the sidecar; promoted to 'completed' by the orchestrator on successful resolution; set to 'entered-in-error' on multiple-matches. Reminder CRs: set to 'active' by the sweeper; promoted to 'completed' by the sidecar after sending the template. Web CRs: set to 'active' by the orchestrator; promoted to 'completed' by web-functions on browser POST; revoked by the session sweeper on TTL expiry.

The status of the communication request.

Captures the reason for the current state of the CommunicationRequest.

This is generally only used for "exception" statuses such as "suspended" or "cancelled". The reason why the CommunicationRequest was created at all is captured in reasonCode, not here. [distinct reason codes for different statuses can be enforced using invariants if they are universal bindings].

Codes identifying the reason for the current state of a request.

Only set on reverse CRs (category=identity-resolution-required, written by the sidecar) and reminder CRs (category=reminder, written by the orchestrator sweeper). Absent on standard outbound CRs. Read by the Subscription criteria to route CRs to the correct queue.

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

Codes for general categories of communications such as alerts, instruction, etc.

Characterizes how quickly the proposed act must be initiated. Includes concepts such as stat, urgent, routine.

Codes indicating the relative importance of a communication request.

If true indicates that the CommunicationRequest is asking for the specified action to not occur.

The attributes provided with the request qualify what is not to be done.

Always present. Set by handleTaskDue from COMMUNICATION_MEDIUM_CODE (default 'whatsapp'). The sidecar's cr-events Subscription filters on medium=whatsapp; web CRs are delivered via a separate path. Configurable via COMMUNICATION_MEDIUM_SYSTEM and COMMUNICATION_MEDIUM_CODE.

Codes for communication mediums such as phone, fax, email, in person, etc.

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.

A reference to a code defined by a terminology system.

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.

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

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.

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

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.

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

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).

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.

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.

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.

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

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.

Present on outbound CRs: set by handleTaskDue to Task.for. May be absent on reverse CRs where the identity is unresolved.

Outbound CRs: set by handleTaskDue to the originating Task reference. Reverse CRs: set by the sidecar to sender hint resources. Not indexed by HAPI (HAPI-0524); the Task↔CR link is carried on Task.output instead.

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

The Encounter during which this CommunicationRequest 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.

Outbound CRs: initial payload set by handleTaskDue to the Questionnaire reference (contentReference). The sidecar appends the QuestionnaireResponse reference once the QR is created (ensureCRPayloadCarriesQRRef). Reverse CRs: payload set by the sidecar to the inbound message text (contentString). The CR↔QR link lives here because QuestionnaireResponse.basedOn is NOT used (HAPI rejects non-CarePlan/ServiceRequest basedOn with HAPI-0931).

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).

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.

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.

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

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

CRUCIAL: QuestionnaireResponse.basedOn is NOT used (HAPI rejects non-CarePlan/ServiceRequest basedOn with HAPI-0931). The CR<->QR link lives on cr.payload[].contentReference.

The time when this communication is to occur.

Present on outbound CRs. Computed by buildDeliveryAnchoredPeriod: start = deliveryTime (when the CR was actually dispatched, not the scheduled time); end = deliveryTime + intended window length (restriction.period.end - restriction.period.start, or TASK_DEFAULT_RESPONSE_WINDOW_MINUTES default 24h). Absent on reminder CRs and reverse CRs. Read by the deadline sweeper to auto-revoke CRs past their response window.

occurrencePeriod.end = deliveryTime + intended-window-length (issue #157). Under queue backpressure, delivery time diverges from scheduled time; anchoring to delivery ensures every reached patient gets the full intended response window.

For draft requests, indicates the date of initial creation. For requests with other statuses, indicates the date of activation.

The device, individual, or organization who initiated the request and has responsibility for its activation.

Outbound CRs: set by handleTaskDue to Task.for (resolved Reference). Reverse CRs: set by the sidecar to a resolved Reference when identity is known, or an identifier-only Reference (phone or BSUID system) when identity is unresolved. Read by the sidecar to address outbound WhatsApp messages.

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

Describes why the request is being made in coded or textual form.

Textual reasons can be captured using reasonCode.text.

Codes for describing reasons for the occurrence of a communication.

Indicates another resource whose existence justifies this request.

Comments made about the request by the requester, sender, recipient, subject or other participants.