3. Artifact index

An identifier - identifies some entity uniquely and unambiguously. Typically this is used for business identifiers.

The structure and format of this Id shall be consistent with the specification corresponding to the formatCode attribute. (e.g. for a DICOM standard document a 64-character numeric UID, for an HL7 CDA format a serialization of the CDA Document Id extension and root in the form "oid^extension", where OID is a 64 digits max, and the Id is a 16 UTF-8 char max. If the OID is coded without the extension then the '^' character shall not be included.).

CDA Document Id extension and root.

An identifier - identifies some entity uniquely and unambiguously. Typically this is used for business identifiers.

The status of this document reference.

This is the status of the DocumentReference object, which might be independent from the docStatus element.

This element is labeled as a modifier because the status contains the codes that mark the document or reference as not currently valid.

Specifies the particular kind of document referenced (e.g. History and Physical, Discharge Summary, Progress Note). This usually equates to the purpose of making the document referenced.

Key metadata element describing the document that describes he exact type of document. Helps humans to assess whether the document is of interest when viewing a list of documents.

Precise type of clinical document.

A categorization for the type of document referenced - helps for indexing and searching. This may be implied by or derived from the code specified in the DocumentReference.type.

Key metadata element describing the the category or classification of the document. This is a broader perspective that groups similar documents based on how they would be used. This is a primary key used in searching.

High-level kind of a clinical document at a macro level.

Who or what the document is about. The document can be about a person, (patient or healthcare practitioner), a device (e.g. a machine) or even a group of subjects (such as a document about a herd of farm animals, or a set of patients that share a common exposure).

When the document reference was created.

Referencing/indexing time is used for tracking, organizing versions and searching.

Identifies the organization or group who is responsible for ongoing maintenance of and access to the document.

Identifies the logical organization (software system, vendor, or department) to go to find the current version, where to report issues, etc. This is different from the physical location (URL, disk drive, or server) of the document, which is the technical location of the document, which host may be delegated to the management of some other organization.

The type of relationship that this document has with anther document.

If this document appends another document, then the document cannot be fully understood without also accessing the referenced document.

The type of relationship between documents.

The target document of this relationship.

Human-readable description of the source document.

Helps humans to assess whether the document is of interest.

What the document is about, a terse summary of the document.

A set of Security-Tag codes specifying the level of privacy/security of the Document. Note that DocumentReference.meta.security contains the security labels of the "reference" to the document, while DocumentReference.securityLabel contains a snapshot of the security labels on the document the reference refers to.

Use of the Health Care Privacy/Security Classification (HCS) system of security-tag use is recommended.

The confidentiality codes can carry multiple vocabulary items. HL7 has developed an understanding of security and privacy tags that might be desirable in a Document Sharing environment, called HL7 Healthcare Privacy and Security Classification System (HCS). The following specification is recommended but not mandated, as the vocabulary bindings are an administrative domain responsibility. The use of this method is up to the policy domain such as the XDS Affinity Domain or other Trust Domain where all parties including sender and recipients are trusted to appropriately tag and enforce.

In the HL7 Healthcare Privacy and Security Classification (HCS) there are code systems specific to Confidentiality, Sensitivity, Integrity, and Handling Caveats. Some values would come from a local vocabulary as they are related to workflow roles and special projects.

Security Labels from the Healthcare Privacy and Security Classification System.

Identifies the type of the data in the attachment and allows a method to be chosen to interpret or render the data. Includes mime type parameters such as charset where appropriate.

Processors of the data need to be able to know how to interpret the data.

The mime type of an attachment. Any valid mime type is allowed.

The human language of the content. The value can be any valid value according to BCP 47.

Users need to be able to choose between the languages in a set of attachments.

A human language.

A location where the data can be accessed.

The data needs to be transmitted by reference.

If both data and url are provided, the url SHALL point to the same content as the data contains. Urls may be relative references or may reference transient locations such as a wrapping envelope using cid: though this has ramifications for using signatures. Relative URLs are interpreted relative to the service url, like a resource reference, rather than relative to the resource itself. If a URL is provided, it SHALL resolve to actual data.

The number of bytes of data that make up this attachment (before base64 encoding, if that is done).

Representing the size allows applications to determine whether they should fetch the content automatically in advance, or refuse to fetch it at all.

The number of bytes is redundant if the data is provided as a base64binary, but is useful if the data is provided as a url reference.

The calculated hash of the data using SHA-1. Represented using base64.

Included so that applications can verify that the contents of a location have not changed due to technical failures (e.g., storage rot, transport glitch, incorrect version).

The hash is calculated on the data prior to base64 encoding, if the data is based64 encoded. The hash is not intended to support digital signatures. Where protection against malicious threats a digital signature should be considered, see Provenance.signature for mechanism to protect a resource with a digital signature.

A label or set of text to display in place of the data.

Applications need a label to display to a human user in place of the actual data if the data cannot be rendered or perceived by the viewer.

The date that the attachment was first created.

This is often tracked as an integrity issue for use of the attachment.

An identifier of the document encoding, structure, and template that the document conforms to beyond the base format indicated in the mimeType.

Note that while IHE mostly issues URNs for format types, not all documents can be identified by a URI.

Describes the clinical encounter or type of care that the document content is associated with.

This list of codes represents the main clinical acts, such as a colonoscopy or an appendectomy, being documented. In some cases, the event is inherent in the type Code, such as a "History and Physical Report" in which the procedure being documented is necessarily a "History and Physical" act.

An event can further specialize the act inherent in the type, such as where it is simply "Procedure Report" and the procedure was a "colonoscopy". If one or more event codes are included, they shall not conflict with the values inherent in the class or type elements as such a conflict would create an ambiguous situation.

This list of codes represents the main clinical acts being documented.

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

If the end of the period is missing, it means that the period is ongoing

The kind of facility where the patient was seen.

XDS Facility Type.

This property may convey specifics about the practice setting where the content was created, often reflecting the clinical specialty.

This is an important piece of metadata that providers often rely upon to quickly sort and/or filter out to find specific content.

This element should be based on a coarse classification system for the class of specialty practice. Recommend the use of the classification system for Practice Setting, such as that described by the Subject Matter Domain in LOINC.

Additional details about where the content was created (e.g. clinical specialty).

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.

The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.

The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).

This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.

Aa resource (or, for logical models, the URI of the logical model).

An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

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.

Related identifiers or resources associated with the DocumentReference.

May be identifiers or resources that caused the DocumentReference or referenced Document to be created.