May be used to represent additional information that is not part of the basic definition of the resource. To make the use of extensions safe and managable, 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 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 managable, 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).

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 property covers the general availability of the resource, not the current value which may be covered by the operationStatus, or by a schedule/slots if they are configured for the location.

Indicates whether the location is still in use.

The operational status covers operation values most relevant to beds (but can also apply to rooms/units/chairs/etc. such as an isolation unit/dialysis chair). This typically covers concepts such as contamination, housekeeping, and other activities like maintenance.

The operational status if the location (where typically a bed/room).

A list of alternate names that the location is known as, or was known as, in the past.

Over time locations and organizations go through many changes and can be known by different names.

For searching knowing previous names that the location was known by can be very useful.

There are no dates associated with the alias/historic names, as this is not intended to track when names were used, but to assist in searching so that older names can still result in identifying the location.

Description of the Location, which helps in finding or referencing the place.

Humans need additional information to verify a correct location has been identified.

Indicates whether a resource instance represents a specific location or a class of locations.

When using a Location resource for scheduling or orders, we need to be able to refer to a class of Locations instead of a specific Location.

This is labeled as a modifier because whether or not the location is a class of locations changes how it can be used and understood.

Indicates whether a resource instance represents a specific location or a class of locations.

Physical location.

If locations can be visited, we need to keep track of their address.

Additional addresses should be recorded using another instance of the Location resource, or via the Organization.

Physical form of the location, e.g. building, room, vehicle, road, virtual.

For purposes of showing relevant locations in queries, we need to categorize locations.

Physical form of the location.

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

A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

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

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.

Identifies the purpose for this identifier, if known .

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.

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

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.

Plain text narrative that identifies the resource in addition to the resource reference.

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

Another Location of which this Location is physically a part of.

For purposes of location, display and identification, knowing which locations are located within other locations is important.

Collection of characteristics (attributes).

These could be such things as is wheelchair accessible.

A custom attribute that could be provided at a service (e.g. Wheelchair accessibiliy).

What days/times during a week is this location usually open, and any exceptions where the location is not available.

This type of information is commonly found published in directories and on websites informing customers when the facility is available.

Specific services within the location may have their own hours which could be shorter (or longer) than the locations hours.

Systems may choose to render availability differently than it is exchanged on the interface. For example, rather than "Mon, Tue, Wed, Thur, Fri from 9am-12am; Mon, Tue, Wed, Thur, Fri from 1pm-5pm" as would be implied by two availableTime repetitions, an application could render this information as "Mon-Fri 9-12am and 1-5pm".

The availableStartTime is the opening time, and the availableEndTime is the closing time.

Connection details of a virtual service (e.g. shared conference call facility with dedicated number/details).

There are two types of virtual meetings that often exist:

• a persistent, virtual meeting room that can only be used for a single purpose at a time,
• and a dynamic virtual meeting room that is generated on demand for a specific purpose.

Implementers may consider using Appointment.virtualService for virtual meeting rooms that are generated on-demand.

Technical endpoints providing access to services operated for the location.

Organizations may have different systems at different locations that provide various services and need to be able to define the technical connection details for how to connect to them, and for what purpose.