If a groups membership is calculated periodically from the memberFilter criteria, a server SHALL populate a valueDateTime with the date the group's membership was last updated. When a date element is populated for the Group, the valueDateTime element SHALL NOT be later than the date in that element, but may be the same datetime or an earlier datetime. If members are calculated dynamically for the group (for example, when a Bulk Export operation is kicked off) this value SHALL be omitted. The server's refresh cycle capabilities and relevent configuration options SHOULD be described in the server's documentation.

A server SHALL support the inclusion of one or more memberFilter modifier extensions containing a valueExpression with a language of application/x-fhir-query and an expression populated with a FHIR REST API query for a resource type included in the Patient or Practitioner compartment. If multiple memberFilter extensions are provided that contain criteria for different resource types, servers SHALL filter the group to only include Patients or Practitioners that have resources in their compartments that meet the conditions in all of the expressions. If multiple memberFilter extensions are provided that contain criteria for a single resource type, the server SHALL include Patients or Practitioners who have resources in their compartments that meet the criteria for that resource type in any of those expressions (a logical "or"). A server MAY also support other expression languages such as text/cql. When more than one lanugage is supported by a server a client SHALL use a single language type for all of the memberFilter expressions included in a single Group.

FHIR search result parameters (such as _sort, _include, and _elements) SHALL NOT be used as memberFilter criteria. Clients should consult the server's capability statement to identify supported search parameters. Servers SHALL reject Group creation requests that include unsupported search parameters in a memberFilter expression. Implementation guides that reference the Bulk Cohort API, should specify required search parameters must be supported for their use case. Other implementations guides that incorporate the Bulk Export operation MAY provide a set of core search parameters that servers implementing the guide need to support.

A client SHALL populate this element with person when creating a group of Patients, or practitioner when creating a group of Practitioners.

A server MAY support the inclusion of one or more member elements that contain an entity element with a reference to a Patient resource, Practitioner resource, or Group resource that is a group of Patient resources or Practitioner resources. When members are provided, the expression in the memberFilter extension for the Group SHALL only be applied to the compartments of the referenced resources, or those of the members of referenced Group resources. When members are not provided and the Group's type element is set to person, the expression in the memberFilter extension SHALL be applied to all of the Patient compartments the client is authorized to access. When members are not provided and the Group's type element is set to practitioner, the expression in the memberFilter extension SHALL be applied to all of the Practitioner compartments the client is authorized to access.

Represents a defined collection of entities that may be discussed or acted upon collectively but which are not expected to act collectively, and are not formally or legally recognized; i.e. a collection of entities that isn't an Organization.

If both Group.characteristic and Group.member are present, then the members are the individuals who were found who met the characteristic. It's possible that there might be other candidate members who meet the characteristic and aren't (yet) in the list. All members SHALL have the listed characteristics.

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.

If a groups membership is calculated periodically from the memberFilter criteria, a server SHALL populate a valueDateTime with the date the group's membership was last updated. When a date element is populated for the Group, the valueDateTime element SHALL NOT be later than the date in that element, but may be the same datetime or an earlier datetime. If members are calculated dynamically for the group (for example, when a Bulk Export operation is kicked off) this value SHALL be omitted. The server's refresh cycle capabilities and relevent configuration options SHOULD be described in the server's documentation.

Extension used by a server to indicate to a client when the members in a dynamic group were last updated

A server SHALL support the inclusion of one or more memberFilter modifier extensions containing a valueExpression with a language of application/x-fhir-query and an expression populated with a FHIR REST API query for a resource type included in the Patient or Practitioner compartment. If multiple memberFilter extensions are provided that contain criteria for different resource types, servers SHALL filter the group to only include Patients or Practitioners that have resources in their compartments that meet the conditions in all of the expressions. If multiple memberFilter extensions are provided that contain criteria for a single resource type, the server SHALL include Patients or Practitioners who have resources in their compartments that meet the criteria for that resource type in any of those expressions (a logical "or"). A server MAY also support other expression languages such as text/cql. When more than one lanugage is supported by a server a client SHALL use a single language type for all of the memberFilter expressions included in a single Group.

FHIR search result parameters (such as _sort, _include, and _elements) SHALL NOT be used as memberFilter criteria. Clients should consult the server's capability statement to identify supported search parameters. Servers SHALL reject Group creation requests that include unsupported search parameters in a memberFilter expression. Implementation guides that reference the Bulk Cohort API, should specify required search parameters must be supported for their use case. Other implementations guides that incorporate the Bulk Export operation MAY provide a set of core search parameters that servers implementing the guide need to support.

Extension to define the population of the group using FHIR REST API parameters

A client SHALL populate this element with person when creating a group of Patients, or practitioner when creating a group of Practitioners.

Group members SHALL be of the appropriate resource type (Patient for person or animal; or Practitioner, Device, Medication or Substance for the other types.).

Identifies what type of resources the group is made up of.

If true, indicates that the resource refers to a specific group of real individuals. If false, the group defines a set of intended individuals.

There are use-cases for groups that define specific collections of individuals, and other groups that define "types" of intended individuals. The requirements for both kinds of groups are similar, so we use a single resource, distinguished by this flag.

A label assigned to the group for human identification and communication.

Used to identify the group in human communication.

Identifies traits whose presence r absence is shared by members of the group.

All the identified characteristics must be true for an entity to a member of the group.

Needs to be a generic mechanism for identifying what individuals can be part of a group.

A server MAY support the inclusion of one or more member elements that contain an entity element with a reference to a Patient resource, Practitioner resource, or Group resource that is a group of Patient resources or Practitioner resources. When members are provided, the expression in the memberFilter extension for the Group SHALL only be applied to the compartments of the referenced resources, or those of the members of referenced Group resources. When members are not provided and the Group's type element is set to person, the expression in the memberFilter extension SHALL be applied to all of the Patient compartments the client is authorized to access. When members are not provided and the Group's type element is set to practitioner, the expression in the memberFilter extension SHALL be applied to all of the Practitioner compartments the client is authorized to access.

Often the only thing of interest about a group is "who's in it".

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.

A reference to the entity that is a member of the group. Must be consistent with Group.type. If the entity is another group, then the type must be the same.

Represents a defined collection of entities that may be discussed or acted upon collectively but which are not expected to act collectively, and are not formally or legally recognized; i.e. a collection of entities that isn't an Organization.

If both Group.characteristic and Group.member are present, then the members are the individuals who were found who met the characteristic. It's possible that there might be other candidate members who meet the characteristic and aren't (yet) in the list. All members SHALL have the listed characteristics.

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.

If a groups membership is calculated periodically from the memberFilter criteria, a server SHALL populate a valueDateTime with the date the group's membership was last updated. When a date element is populated for the Group, the valueDateTime element SHALL NOT be later than the date in that element, but may be the same datetime or an earlier datetime. If members are calculated dynamically for the group (for example, when a Bulk Export operation is kicked off) this value SHALL be omitted. The server's refresh cycle capabilities and relevent configuration options SHOULD be described in the server's documentation.

Extension used by a server to indicate to a client when the members in a dynamic group were last updated

A server SHALL support the inclusion of one or more memberFilter modifier extensions containing a valueExpression with a language of application/x-fhir-query and an expression populated with a FHIR REST API query for a resource type included in the Patient or Practitioner compartment. If multiple memberFilter extensions are provided that contain criteria for different resource types, servers SHALL filter the group to only include Patients or Practitioners that have resources in their compartments that meet the conditions in all of the expressions. If multiple memberFilter extensions are provided that contain criteria for a single resource type, the server SHALL include Patients or Practitioners who have resources in their compartments that meet the criteria for that resource type in any of those expressions (a logical "or"). A server MAY also support other expression languages such as text/cql. When more than one lanugage is supported by a server a client SHALL use a single language type for all of the memberFilter expressions included in a single Group.

FHIR search result parameters (such as _sort, _include, and _elements) SHALL NOT be used as memberFilter criteria. Clients should consult the server's capability statement to identify supported search parameters. Servers SHALL reject Group creation requests that include unsupported search parameters in a memberFilter expression. Implementation guides that reference the Bulk Cohort API, should specify required search parameters must be supported for their use case. Other implementations guides that incorporate the Bulk Export operation MAY provide a set of core search parameters that servers implementing the guide need to support.

Extension to define the population of the group using FHIR REST API parameters

A unique business identifier for this group.

Allows the group to be referenced from external specifications.

Indicates whether the record for the group is available for use or is merely being retained for historical purposes.

Need to be able to mark a group record as not to be used because it was created in error or is otherwise no longer available (e.g. a herd that no longer exists).

A client SHALL populate this element with person when creating a group of Patients, or practitioner when creating a group of Practitioners.

Group members SHALL be of the appropriate resource type (Patient for person or animal; or Practitioner, Device, Medication or Substance for the other types.).

Identifies what type of resources the group is made up of.

If true, indicates that the resource refers to a specific group of real individuals. If false, the group defines a set of intended individuals.

There are use-cases for groups that define specific collections of individuals, and other groups that define "types" of intended individuals. The requirements for both kinds of groups are similar, so we use a single resource, distinguished by this flag.

Provides a specific type of resource the group includes; e.g. "cow", "syringe", etc.

This would generally be omitted for Person resources.

Kind of particular resource; e.g. cow, syringe, lake, etc.

A label assigned to the group for human identification and communication.

Used to identify the group in human communication.

A count of the number of resource instances that are part of the group.

Note that the quantity may be less than the number of members if some of the members are not active.

Group size is a common defining characteristic.

Entity responsible for defining and maintaining Group characteristics and/or registered members.

This does not strictly align with ownership of a herd or flock, but may suffice to represent that relationship in simple cases. More complex cases will require an extension.

Identifies traits whose presence r absence is shared by members of the group.

All the identified characteristics must be true for an entity to a member of the group.

Needs to be a generic mechanism for identifying what individuals can be part of a group.

A server MAY support the inclusion of one or more member elements that contain an entity element with a reference to a Patient resource, Practitioner resource, or Group resource that is a group of Patient resources or Practitioner resources. When members are provided, the expression in the memberFilter extension for the Group SHALL only be applied to the compartments of the referenced resources, or those of the members of referenced Group resources. When members are not provided and the Group's type element is set to person, the expression in the memberFilter extension SHALL be applied to all of the Patient compartments the client is authorized to access. When members are not provided and the Group's type element is set to practitioner, the expression in the memberFilter extension SHALL be applied to all of the Practitioner compartments the client is authorized to access.

Often the only thing of interest about a group is "who's in it".

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.

A reference to the entity that is a member of the group. Must be consistent with Group.type. If the entity is another group, then the type must be the same.

The period that the member was in the group, if known.

Need to track who was in a group at a particular time.

A flag to indicate that the member is no longer in the group, but previously may have been a member.

Sometimes you don't know when someone stopped being in a group, but not when.