DocumentReference serves as a metadata wrapper for clinical documents, providing indexing, discovery, and context for documents such as PDFs, reports, referral letters, and other healthcare documentation. In Polaris, all document content must be included inline as base64-encoded data to ensure reliable access and simplified security management.

The resource captures:

• Document identification and categorization
• Clinical context and temporal relevance
• Authorship and authentication details
• The actual document content (inline)
• Relationships to other documents

Usually, this is used for documents other than those defined by FHIR.

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 URI that identifies the EMR pipeline and version from which this resource originated. This tells you which EMR instance (recommend using the instance identifier), and the version of the pipeline code/transformations.

In the provenance resource, this corresponds to Provenance.entity.what[x]. The exact use of the source (and the implied Provenance.entity.role) is left to implementer discretion. Only one nominated source is allowed; for additional provenance details, a full Provenance resource should be used.

This element can be used to indicate where the current master source of a resource that has a canonical URL if the resource is no longer hosted at the canonical URL.

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.

A human-readable narrative that contains a summary of the document reference. This narrative should provide key information about the document for human interpretation, including document type, date, and key clinical context.

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.

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.

Unique business identifiers assigned to this document reference.

At least one identifier MUST follow the Polaris naming pattern for cross-system tracking and validation.

When a source/local 'raw code' identifier exists (e.g. from source EMR), it SHOULD be included as an additional identifier.

If the raw code's system is known and appropriate, use that. If no recognized system exists, implementers MAY: • invent a URI for the system, OR • use the fallback URI template: https://fhir.apps.health/NamingSystem/<instance-id>-documentreference-raw-code

The primary Polaris identifier for this document reference, following the standard Polaris naming pattern

The purpose of this identifier.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Identifies the purpose for this identifier, if known .

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

Must match the pattern: https://fhir.apps.health/NamingSystem/<instance-id>-documentreference-identifier

Example: https://fhir.apps.health/NamingSystem/oscar-ab5c8d9f-documentreference-identifier

There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

The original raw identifier(s) from the source EMR system

The purpose of this identifier.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Identifies the purpose for this identifier, if known .

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

URI identifying the code system for the raw code. If the system is known, use the appropriate URI. If unknown, use a constructed URI or the fallback: https://fhir.apps.health/NamingSystem/\<instance-id>-documentreference-raw-code

Identifier.system is always case sensitive.

There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

The status of this document reference. Allowed values:

• current: The document is active and current
• superseded: The document has been replaced by a newer version
• entered-in-error: The document was created in error and should not be used (deleted)

When a document is updated, the previous version can be marked as 'superseded' and a new DocumentReference created with status 'current'. This approach:

• Maintains immutable document history
• Provides clear version tracking
• Enables audit trails
• Supports document lifecycle management

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.

The status of the document reference.

Specifies the precise type of clinical document referenced (e.g., specific LOINC code for document type). While this field is supported for backward compatibility with systems expecting it, Polaris strongly recommends using 'category' instead because:

• Category supports multiple classifications per document
• Category allows both clinical and administrative taxonomies
• Type is limited to a single classification

If used, prefer LOINC codes for interoperability.

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.

LOINC document type codes

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.

LOINC code for document type when available

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.

Original document type code from source EMR 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.

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.

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.

High-level categorization of the document. This is the PREFERRED method for document classification in Polaris. Multiple categories can be assigned to provide different perspectives on the document's purpose and content.

Common categories include:

• Clinical notes (progress notes, consultation notes)
• Diagnostic reports (lab results, imaging reports)
• Administrative documents (referrals, discharge summaries)
• Legal documents (consent forms, advance directives)

Use standard terminologies (LOINC, SNOMED CT) for maximum interoperability.

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.

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.

Standard terminology code for document category. Not required, but helpful if available.

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.

Original category code from source EMR 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.

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.

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.

The patient that this document pertains to. This is a required field that must reference a valid PolarisCorePatient resource. The reference should use the patient's identifier for reliable cross-system identification.

While the FHIR standard allows documents about other subjects (Device, Practitioner, Group), Polaris currently only supports patient-centric documents to align with Canadian healthcare requirements.

When this DocumentReference resource was created in the system. This is NOT necessarily when the document itself was created or when the documented service occurred.

Timing relationships:

• date: When DocumentReference was created (this field)
• content.attachment.creation: When document was created
• context.period: When clinical service occurred

Example: A discharge summary for April 10-15 admission might be:

• Service period: 2025-04-10 to 2025-04-15
• Document created: 2025-04-15T14:00:00
• DocumentReference created: 2025-04-16T09:00:00 (next day upload)

This field is primarily for technical/audit purposes.

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

Identifies who was responsible for writing the document content. Can include multiple authors for collaborative documents. Note the distinction:

• Author: Who wrote/created the content

• Authenticator: Who legally verified/signed the document

• Custodian: Organization maintaining the document

• in EMRs, you probably want to be using 'authenticator' rather than 'author' here.

  • eg: 'author' may be a medical student, 'authenticator' could be the doc signing off.
  • 'authenticator' is the person who is medically responsible for the content of this document.

Authors can only be EMR users in this context (represented by PolarisCorePractitionerRole)

Order matters - list primary author first.

Not necessarily who did the actual data entry (i.e. typist) or who was the source (informant).

The practitioner who has legally authenticated or verified this document, taking responsibility for its content. This represents medical/legal responsibility rather than authorship. The authenticator:

• Must have appropriate authority/credentials
• Takes responsibility for document accuracy
• May or may not be the document author
• Should be a single practitioner (not multiple)

Typically the attending physician, consultant, or supervising practitioner. Reference must be to a PolarisCorePractitionerRole to capture both practitioner and their role.

Represents a participant within the author institution who has legally authenticated or attested the document. Legal authentication implies that a document has been signed manually or electronically by the legal Authenticator.

The organization that is responsible for maintaining the authoritative source of this document and controlling access to it. This is a REQUIRED field that identifies:

• Who has stewardship of the document
• Where to direct queries about the document
• Who is responsible for retention policies
• Who manages access permissions

Typically the organization that created the document or currently manages the patient's care. Must reference a valid PolarisCoreOrganization resource.

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.

A human-readable description of the document's content and purpose. While optional, this field is strongly recommended as it:

• Provides quick context without opening the document
• Improves searchability and discoverability
• Helps users identify relevant documents quickly
• Supports accessibility requirements

Should be concise but informative (typically 1-2 sentences).

Examples:

• "Complete blood count showing mild anemia, hemoglobin 10.2"
• "Cardiology consultation for chest pain, recommending stress test"
• "Discharge summary following 5-day admission for pneumonia"

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

Helps humans to assess whether the document is of interest.

The actual document content and associated metadata. Each content element represents one attachment. While Polaris supports multiple attachments per DocumentReference (e.g., referral letter plus supporting test results), most use cases involve a single document.

IMPORTANT: All content MUST be provided inline as base64-encoded data. External URLs are NOT supported due to:

• Security concerns with external resource access
• Reliability issues with external dependencies
• Simplified access control management
• Guaranteed content availability

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 document attachment containing the actual content. This is a REQUIRED element that must include the document data inline. The attachment data type provides:

• Binary content storage via base64 encoding
• MIME type identification
• Human-readable titles
• Size tracking
• Language specification

No URL field should be populated - all data must be in the 'data' element.

MIME type identifying the document format. This is REQUIRED to ensure proper handling and display of the document. Common values:

• 'application/pdf' - PDF documents (most common)
• 'text/plain' - Plain text documents
• 'text/html' - HTML formatted documents
• 'text/rtf' - Rich text format
• 'image/jpeg' - JPEG images (scanned documents)
• 'image/png' - PNG images
• 'application/msword' - Microsoft Word
• 'application/vnd.openxmlformats-officedocument.wordprocessingml.document' - Word DOCX

The MIME type must accurately reflect the actual content format.

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

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

BCP-47 language tag indicating the human language of the document content. Important for:

• Multilingual healthcare settings
• Accessibility requirements
• Content filtering/searching
• Translation workflows

Common values:

• 'en-CA' - Canadian English
• 'fr-CA' - Canadian French
• 'en' - English (generic)
• 'fr' - French (generic)
• 'es' - Spanish

Example: A discharge summary in French would have language = 'fr-CA'

A human language.

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

The actual document content as base64-encoded binary data. This is a REQUIRED field containing the complete document. Base64 encoding converts binary data to ASCII text for safe transport in JSON/XML.

Implementation notes:

• Maximum recommended size: 5MB (larger documents should be compressed first)
• Line breaks in base64 string should be avoided
• Standard base64 alphabet (A-Z, a-z, 0-9, +, /)

Example encoding (JavaScript):

const base64Data = Buffer.from(fileContent).toString('base64');

Example encoding (Python):

import base64
base64_data = base64.b64encode(file_content).decode('utf-8')

The base64-encoded data SHALL be expressed in the same character set as the base resource XML or JSON.

The data needs to able to be transmitted inline.

Human-readable title for the document. While optional, this field is strongly recommended for user experience. The title should be:

• Descriptive and meaningful
• Suitable for display in document lists
• Include relevant context (e.g., date, type)
• 50-100 characters typically

Examples:

• "Discharge Summary - April 15, 2025"
• "CBC Results - Hemoglobin 10.2"
• "Cardiology Referral - Dr. Smith"
• "Chest X-Ray Report - Normal"

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/time when the document was originally created (not when the DocumentReference was created). Useful for:

• Distinguishing between multiple versions
• Understanding document timeline
• Sorting documents chronologically
• Audit trail purposes

Format: FHIR dateTime (e.g., "2025-04-20T10:00:00-06:00")

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

The clinical context in which the document was prepared.

These values are primarily added to help with searching for interesting/relevant documents.

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.

Encounter(s) related to the document content. Links the document to specific clinical visits, admissions, or other healthcare interactions. Multiple encounters can be referenced if the document spans multiple visits.

Examples:

• Discharge summary → Inpatient admission encounter
• Consultation note → Outpatient consultation encounter
• Operative report → Surgical encounter
• Progress note → Daily hospital round encounter

Providing encounter context enables:

• Grouping documents by visit
• Understanding care continuity
• Encounter-based searches
• Billing/administrative workflows

The time period over which the service described by the document was provided. This represents the clinical relevance timeframe, not when the document was created. Critical for understanding temporal context.

Examples:

• Discharge summary: Admission to discharge dates
• Consultation note: Consultation appointment time
• Progress note: Specific day of care
• Procedure report: Surgery start to end time

If only a point in time is relevant, use 'start' only. For ongoing care, 'end' may be absent.

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.

DocumentReference serves as a metadata wrapper for clinical documents, providing indexing, discovery, and context for documents such as PDFs, reports, referral letters, and other healthcare documentation. In Polaris, all document content must be included inline as base64-encoded data to ensure reliable access and simplified security management.

The resource captures:

• Document identification and categorization
• Clinical context and temporal relevance
• Authorship and authentication details
• The actual document content (inline)
• Relationships to other documents

A URI that identifies the EMR pipeline and version from which this resource originated. This tells you which EMR instance (recommend using the instance identifier), and the version of the pipeline code/transformations.

A human-readable narrative that contains a summary of the document reference. This narrative should provide key information about the document for human interpretation, including document type, date, and key clinical context.

Unique business identifiers assigned to this document reference.

At least one identifier MUST follow the Polaris naming pattern for cross-system tracking and validation.

When a source/local 'raw code' identifier exists (e.g. from source EMR), it SHOULD be included as an additional identifier.

If the raw code's system is known and appropriate, use that. If no recognized system exists, implementers MAY: • invent a URI for the system, OR • use the fallback URI template: https://fhir.apps.health/NamingSystem/<instance-id>-documentreference-raw-code

The primary Polaris identifier for this document reference, following the standard Polaris naming pattern

Must match the pattern: https://fhir.apps.health/NamingSystem/<instance-id>-documentreference-identifier

Example: https://fhir.apps.health/NamingSystem/oscar-ab5c8d9f-documentreference-identifier

The original raw identifier(s) from the source EMR system

URI identifying the code system for the raw code. If the system is known, use the appropriate URI. If unknown, use a constructed URI or the fallback: https://fhir.apps.health/NamingSystem/\<instance-id>-documentreference-raw-code

The status of this document reference. Allowed values:

• current: The document is active and current
• superseded: The document has been replaced by a newer version
• entered-in-error: The document was created in error and should not be used (deleted)

When a document is updated, the previous version can be marked as 'superseded' and a new DocumentReference created with status 'current'. This approach:

• Maintains immutable document history
• Provides clear version tracking
• Enables audit trails
• Supports document lifecycle management

Specifies the precise type of clinical document referenced (e.g., specific LOINC code for document type). While this field is supported for backward compatibility with systems expecting it, Polaris strongly recommends using 'category' instead because:

• Category supports multiple classifications per document
• Category allows both clinical and administrative taxonomies
• Type is limited to a single classification

If used, prefer LOINC codes for interoperability.

LOINC document type codes

LOINC code for document type when available

Original document type code from source EMR system

High-level categorization of the document. This is the PREFERRED method for document classification in Polaris. Multiple categories can be assigned to provide different perspectives on the document's purpose and content.

Common categories include:

• Clinical notes (progress notes, consultation notes)
• Diagnostic reports (lab results, imaging reports)
• Administrative documents (referrals, discharge summaries)
• Legal documents (consent forms, advance directives)

Use standard terminologies (LOINC, SNOMED CT) for maximum interoperability.

Standard terminology code for document category. Not required, but helpful if available.

Original category code from source EMR system

The patient that this document pertains to. This is a required field that must reference a valid PolarisCorePatient resource. The reference should use the patient's identifier for reliable cross-system identification.

While the FHIR standard allows documents about other subjects (Device, Practitioner, Group), Polaris currently only supports patient-centric documents to align with Canadian healthcare requirements.

When this DocumentReference resource was created in the system. This is NOT necessarily when the document itself was created or when the documented service occurred.

Timing relationships:

• date: When DocumentReference was created (this field)
• content.attachment.creation: When document was created
• context.period: When clinical service occurred

Example: A discharge summary for April 10-15 admission might be:

• Service period: 2025-04-10 to 2025-04-15
• Document created: 2025-04-15T14:00:00
• DocumentReference created: 2025-04-16T09:00:00 (next day upload)

This field is primarily for technical/audit purposes.

Identifies who was responsible for writing the document content. Can include multiple authors for collaborative documents. Note the distinction:

• Author: Who wrote/created the content

• Authenticator: Who legally verified/signed the document

• Custodian: Organization maintaining the document

• in EMRs, you probably want to be using 'authenticator' rather than 'author' here.

  • eg: 'author' may be a medical student, 'authenticator' could be the doc signing off.
  • 'authenticator' is the person who is medically responsible for the content of this document.

Authors can only be EMR users in this context (represented by PolarisCorePractitionerRole)

Order matters - list primary author first.

The practitioner who has legally authenticated or verified this document, taking responsibility for its content. This represents medical/legal responsibility rather than authorship. The authenticator:

• Must have appropriate authority/credentials
• Takes responsibility for document accuracy
• May or may not be the document author
• Should be a single practitioner (not multiple)

Typically the attending physician, consultant, or supervising practitioner. Reference must be to a PolarisCorePractitionerRole to capture both practitioner and their role.

The organization that is responsible for maintaining the authoritative source of this document and controlling access to it. This is a REQUIRED field that identifies:

• Who has stewardship of the document
• Where to direct queries about the document
• Who is responsible for retention policies
• Who manages access permissions

Typically the organization that created the document or currently manages the patient's care. Must reference a valid PolarisCoreOrganization resource.

A human-readable description of the document's content and purpose. While optional, this field is strongly recommended as it:

• Provides quick context without opening the document
• Improves searchability and discoverability
• Helps users identify relevant documents quickly
• Supports accessibility requirements

Should be concise but informative (typically 1-2 sentences).

Examples:

• "Complete blood count showing mild anemia, hemoglobin 10.2"
• "Cardiology consultation for chest pain, recommending stress test"
• "Discharge summary following 5-day admission for pneumonia"

The actual document content and associated metadata. Each content element represents one attachment. While Polaris supports multiple attachments per DocumentReference (e.g., referral letter plus supporting test results), most use cases involve a single document.

IMPORTANT: All content MUST be provided inline as base64-encoded data. External URLs are NOT supported due to:

• Security concerns with external resource access
• Reliability issues with external dependencies
• Simplified access control management
• Guaranteed content availability

The document attachment containing the actual content. This is a REQUIRED element that must include the document data inline. The attachment data type provides:

• Binary content storage via base64 encoding
• MIME type identification
• Human-readable titles
• Size tracking
• Language specification

No URL field should be populated - all data must be in the 'data' element.

MIME type identifying the document format. This is REQUIRED to ensure proper handling and display of the document. Common values:

• 'application/pdf' - PDF documents (most common)
• 'text/plain' - Plain text documents
• 'text/html' - HTML formatted documents
• 'text/rtf' - Rich text format
• 'image/jpeg' - JPEG images (scanned documents)
• 'image/png' - PNG images
• 'application/msword' - Microsoft Word
• 'application/vnd.openxmlformats-officedocument.wordprocessingml.document' - Word DOCX

The MIME type must accurately reflect the actual content format.

BCP-47 language tag indicating the human language of the document content. Important for:

• Multilingual healthcare settings
• Accessibility requirements
• Content filtering/searching
• Translation workflows

Common values:

• 'en-CA' - Canadian English
• 'fr-CA' - Canadian French
• 'en' - English (generic)
• 'fr' - French (generic)
• 'es' - Spanish

Example: A discharge summary in French would have language = 'fr-CA'

The actual document content as base64-encoded binary data. This is a REQUIRED field containing the complete document. Base64 encoding converts binary data to ASCII text for safe transport in JSON/XML.

Implementation notes:

• Maximum recommended size: 5MB (larger documents should be compressed first)
• Line breaks in base64 string should be avoided
• Standard base64 alphabet (A-Z, a-z, 0-9, +, /)

Example encoding (JavaScript):

const base64Data = Buffer.from(fileContent).toString('base64');

Example encoding (Python):

import base64
base64_data = base64.b64encode(file_content).decode('utf-8')

Human-readable title for the document. While optional, this field is strongly recommended for user experience. The title should be:

• Descriptive and meaningful
• Suitable for display in document lists
• Include relevant context (e.g., date, type)
• 50-100 characters typically

Examples:

• "Discharge Summary - April 15, 2025"
• "CBC Results - Hemoglobin 10.2"
• "Cardiology Referral - Dr. Smith"
• "Chest X-Ray Report - Normal"

The date/time when the document was originally created (not when the DocumentReference was created). Useful for:

• Distinguishing between multiple versions
• Understanding document timeline
• Sorting documents chronologically
• Audit trail purposes

Format: FHIR dateTime (e.g., "2025-04-20T10:00:00-06:00")

Encounter(s) related to the document content. Links the document to specific clinical visits, admissions, or other healthcare interactions. Multiple encounters can be referenced if the document spans multiple visits.

Examples:

• Discharge summary → Inpatient admission encounter
• Consultation note → Outpatient consultation encounter
• Operative report → Surgical encounter
• Progress note → Daily hospital round encounter

Providing encounter context enables:

• Grouping documents by visit
• Understanding care continuity
• Encounter-based searches
• Billing/administrative workflows

The time period over which the service described by the document was provided. This represents the clinical relevance timeframe, not when the document was created. Critical for understanding temporal context.

Examples:

• Discharge summary: Admission to discharge dates
• Consultation note: Consultation appointment time
• Progress note: Specific day of care
• Procedure report: Surgery start to end time

If only a point in time is relevant, use 'start' only. For ongoing care, 'end' may be absent.

DocumentReference serves as a metadata wrapper for clinical documents, providing indexing, discovery, and context for documents such as PDFs, reports, referral letters, and other healthcare documentation. In Polaris, all document content must be included inline as base64-encoded data to ensure reliable access and simplified security management.

The resource captures:

• Document identification and categorization
• Clinical context and temporal relevance
• Authorship and authentication details
• The actual document content (inline)
• Relationships to other documents

Usually, this is used for documents other than those defined by FHIR.

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.

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 version specific identifier, as it appears in the version portion of the URL. This value changes when the resource is created, updated, or deleted.

The server assigns this value, and ignores what the client specifies, except in the case that the server is imposing version integrity on updates/deletes.

When the resource last changed - e.g. when the version changed.

This value is always populated except when the resource is first being created. The server / resource manager sets this value; what a client provides is irrelevant. This is equivalent to the HTTP Last-Modified and SHOULD have the same value on a read interaction.

A URI that identifies the EMR pipeline and version from which this resource originated. This tells you which EMR instance (recommend using the instance identifier), and the version of the pipeline code/transformations.

In the provenance resource, this corresponds to Provenance.entity.what[x]. The exact use of the source (and the implied Provenance.entity.role) is left to implementer discretion. Only one nominated source is allowed; for additional provenance details, a full Provenance resource should be used.

This element can be used to indicate where the current master source of a resource that has a canonical URL if the resource is no longer hosted at the canonical URL.

A list of profiles (references to StructureDefinition resources) that this resource claims to conform to. The URL is a reference to StructureDefinition.url.

It is up to the server and/or other infrastructure of policy to determine whether/how these claims are verified and/or updated over time. The list of profile URLs is a set.

Security labels applied to this resource. These tags connect specific resources to the overall security policy and infrastructure.

The security labels can be updated without changing the stated version of the resource. The list of security labels is a set. Uniqueness is based the system/code, and version and display are ignored.

Security Labels from the Healthcare Privacy and Security Classification System.

Tags applied to this resource. Tags are intended to be used to identify and relate resources to process and workflow, and applications are not required to consider the tags when interpreting the meaning of a resource.

The tags can be updated without changing the stated version of the resource. The list of tags is a set. Uniqueness is based the system/code, and version and display are ignored.

Codes that represent various types of tags, commonly workflow-related; e.g. "Needs review by Dr. Jones".

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 document reference. This narrative should provide key information about the document for human interpretation, including document type, date, and key clinical context.

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.

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 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 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.

Document identifier as assigned by the source of the document. This identifier is specific to this version of the document. This unique identifier may be used elsewhere to identify this version of the document.

CDA Document Id extension and root.

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.).

Unique business identifiers assigned to this document reference.

At least one identifier MUST follow the Polaris naming pattern for cross-system tracking and validation.

When a source/local 'raw code' identifier exists (e.g. from source EMR), it SHOULD be included as an additional identifier.

If the raw code's system is known and appropriate, use that. If no recognized system exists, implementers MAY: • invent a URI for the system, OR • use the fallback URI template: https://fhir.apps.health/NamingSystem/<instance-id>-documentreference-raw-code

The primary Polaris identifier for this document reference, following the standard Polaris naming pattern

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 purpose of this identifier.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Identifies the purpose for this identifier, if known .

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

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

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.

Allows users to make use of identifiers when the identifier system is not known.

Must match the pattern: https://fhir.apps.health/NamingSystem/<instance-id>-documentreference-identifier

Example: https://fhir.apps.health/NamingSystem/oscar-ab5c8d9f-documentreference-identifier

There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

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.

The original raw identifier(s) from the source EMR system

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 purpose of this identifier.

Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

Identifies the purpose for this identifier, if known .

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

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

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.

Allows users to make use of identifiers when the identifier system is not known.

URI identifying the code system for the raw code. If the system is known, use the appropriate URI. If unknown, use a constructed URI or the fallback: https://fhir.apps.health/NamingSystem/\<instance-id>-documentreference-raw-code

Identifier.system is always case sensitive.

There are many sets of identifiers. To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

The portion of the identifier typically relevant to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986. The value's primary purpose is computational mapping. As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.) A value formatted for human display can be conveyed using the Rendered Value extension. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

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.

The status of this document reference. Allowed values:

• current: The document is active and current
• superseded: The document has been replaced by a newer version
• entered-in-error: The document was created in error and should not be used (deleted)

When a document is updated, the previous version can be marked as 'superseded' and a new DocumentReference created with status 'current'. This approach:

• Maintains immutable document history
• Provides clear version tracking
• Enables audit trails
• Supports document lifecycle management

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.

The status of the document reference.

The status of the underlying document.

The document that is pointed to might be in various lifecycle states.

Status of the underlying document.

Specifies the precise type of clinical document referenced (e.g., specific LOINC code for document type). While this field is supported for backward compatibility with systems expecting it, Polaris strongly recommends using 'category' instead because:

• Category supports multiple classifications per document
• Category allows both clinical and administrative taxonomies
• Type is limited to a single classification

If used, prefer LOINC codes for interoperability.

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.

LOINC document type codes

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.

LOINC code for document type when available

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.

Original document type code from source EMR 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.

High-level categorization of the document. This is the PREFERRED method for document classification in Polaris. Multiple categories can be assigned to provide different perspectives on the document's purpose and content.

Common categories include:

• Clinical notes (progress notes, consultation notes)
• Diagnostic reports (lab results, imaging reports)
• Administrative documents (referrals, discharge summaries)
• Legal documents (consent forms, advance directives)

Use standard terminologies (LOINC, SNOMED CT) for maximum interoperability.

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.

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.

Standard terminology code for document category. Not required, but helpful if available.

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.