HL7 Clinical Document Architecture, Release 2.0

• CDA Schema
  • CDA Schema :: Progress Note section-level template applied.
    • CDA Schema :: Progress Note section-level and Vital Signs entry-level template applied.
      • CDA Schema :: Endocrinology Progress Note section-level and Vital Signs entry-level template applied.
      • CDA Schema :: Progress Note section-level and ICU Vital Signs entry-level template applied.
  • CDA Schema :: Cardiology Progress Note section-level template applied
    • CDA Schema :: Cardiology Progress Note section-level and Cardiac Exam entry-level template applied.
  • CDA Schema :: Endocrinology Progress Note section-level template applied.
    • CDA Schema :: Endocrinology Progress Note section-level and Vital Signs entry-level template applied.

Represents the unique instance identifier of a clinical document.

The code specifying the particular kind of document (e.g. History and Physical, Discharge Summary, Progress Note). The value set is drawn from LOINC, and has a CWE coding strength.

Within the LOINC database, beginning with version 2.09, May 2003, document type codes are those that have a value of "DOC" in the Scale component. This subset of LOINC is included in the appendix (see LOINC Document Codes).

Note: The hierarchical relationship among LOINC document codes is in evolution. Per the LOINC version 2.14 (December 2004) manual: As soon as possible, the component terms used in the creation of the names of document type codes will be mapped to either the UMLS Metathesaurus or SNOMED CT. This mapping will help to establish the meaning of the terms and will allow aggregation and classification of document type codes based on definitions, computable relationships, and subsumption hierarchies that exist in the reference terminology.

Represents the title of the document. It's commonly the case that clinical documents do not have a title, and are collectively referred to by the display name of ClinicalDocument.code (e.g. a "consultation" or "progress note"). Where these display names are rendered to the clinician, or where the document has a unique title, the ClinicalDocument.title component should be used. In the example document in the appendix (see Sample Document), the value of ClinicalDocument.title = "Good Health Clinic Consultation Note".

Signifies the document creation time, when the document first came into being. Where the CDA document is a transform from an original document in some other format, the ClinicalDocument.effectiveTime is the time the original document is created. The time when the transform occurred is not currently represented in CDA.

Confidentiality is a required contextual component of CDA, where the value expressed in the header holds true for the entire document, unless overridden by a nested value (as further described in CDA Context).

* The codeSystem value is included here because confidentialityCode is of type CE, and therefore must carry both a code and a codeSystem.

Specifies the human language of character data (whether they be in contents or attribute values). The values of the attribute are language identifiers as defined by the IETF (Internet Engineering Task Force) RFC 3066 for the Identification of Languages, ed. H. Alvestrand. 1995, which obsoletes RFC 1766. The HL7 code system for these values is "2.16.840.1.113883.6.121". Language is a contextual component of CDA, where the value expressed in the header holds true for the entire document, unless overridden by a nested value (as further described in CDA Context).

Represents an identifier that is common across all document revisions.

An integer value used to version successive replacement documents.

Represents the time a document is released (i.e. copied or sent to a display device) from a document management system that maintains revision control over the document. Once valued, it cannot be changed. The intent is to give the viewer of the document some notion as to how long the document has been out of the safe context of its document management system.

Included for backwards compatibility with CDA, Release One. ClinicalDocument.copyTime has been deprecated because it is not part of the document at the time it is authenticated, but instead represents metadata about the document, applied at some variable time after authentication. Further use is discouraged.

Represents a participant who has attested to the accuracy of the document, but who does not have privileges to legally authenticate the document. An example would be a resident physician who sees a patient and dictates a note, then later signs it. (See also legalAuthenticator)

A clinical document can have zero to many authenticators. While electronic signatures are not captured in a CDA document, both authentication and legal authentication require that a document has been signed manually or electronically by the responsible individual. An authenticator has a required authenticator.time indicating the time of authentication, and a required authenticator.signatureCode, indicating that a signature has been obtained and is on file.

An authenticator is a person in the role of an assigned entity (AssignedEntity class). An assigned entity is a person assigned to the role by the scoping organization. The entity playing the role is a person (Person class). The entity scoping the role is an organization (Organization class). (See here for a description of "player" and "scoper" role associations.)

A scoping organization can be part of a larger organization. Where there is a need to include whole-part relationships, the OrganizationPartOf role can be used. OrganizationPartOf.statusCode indicates the state of the whole-part relationship (e.g. "active", "terminated"). OrganizationPartOf.effectiveTime is an interval of time specifying the period during which the whole-part relationhship is in effect, if such time limit is applicable and known.

Represents the humans and/or machines that authored the document.

In some cases, the role or function of the author is inherent in the ClinicalDocument.code, such as where ClinicalDocument.code is "Medical Student Progress Note". The role of the author can also be recorded in the Author.functionCode or AssignedAuthor.code attribute. If either of these attributes is included, they should be equivalent to or further specialize the role inherent in the ClinicalDocument.code (such as where the ClinicalDocument.code is simply "Physician Progress Note" and the value of Author.functionCode is "rounding physician"), and shall not conflict with the role inherent in the ClinicalDocument.code, as such a conflict would constitute an ambiguous situation.

An author is a person in the role of an assigned author (AssignedAuthor class). The entity playing the role is a person (Person class) or a device (AuthoringDevice class). The entity scoping the role is an organization (Organization class), and is the organization from which the document originates.

Note: In CDA, Release One, it was possible to specify those individuals responsible for the device. This functionality has been deprecated in CDA, Release Two. The MaintainedEntity class is present for backwards compatibility, and its use is discouraged, except where needed to support the transformation of CDA, Release One documents.

Represents the organization that is in charge of maintaining the document. The custodian is the steward that is entrusted with the care of the document. Every CDA document has exactly one custodian.

The custodian participation satisfies the CDA definition of Stewardship (see What is the CDA). Because CDA is an exchange standard and may not represent the original form of the authenticated document, the custodian represents the steward of the original source document.

A custodian is a scoping organization in the role of an assigned custodian (AssignedCustodian class). The steward organization (CustodianOrganization class) is an entity scoping the role of AssignedCustodian, and has a required CustodianOrganization.id.

Represents the participant who has transformed a dictated note into text.

See EncompassingEncounter for a description of the encounterParticipant participant.

An informant (or source of information) is a person that provides relevant information, such as the parent of a comatose patient who describes the patient's behavior prior to the onset of coma.

An informant can be a person in one of two roles. The RelatedEntity role is used to represent an informant without a role.id (e.g. a parent or guy on the street). The informant in this case bears some formal or personal relationship to the patient. The role is unscoped, with the assumption that the patient is always the implied scoper. RelatedEntity.code can be used to specify the nature of the relationship. The AssignedEntity role is used for an identified informant, and is scoped by an Organization.

Represents a recipient who should receive a copy of the document.

Note: The information recipient is an entity to whom a copy of a document is directed, at the time of document authorship. It is not the same as the cumulative set of persons to whom the document has subsequently been disclosed, over the life-time of the patient. Such a disclosure list would not be contained within the document, and it outside the scope of CDA.

Where a person is the intended recipient (IntendedRecipient class), the playing entity is a person (Person class), optionally scoped by an organization (Organization class). Where the intended recipient is an organization, the IntendedRecipient.classCode is valued with "ASSIGNED", and the recipient is reflected by the presence of a scoping Organization, without a playing entity. Where a health chart is the intended recipient, the IntendedRecipient.classCode is valued with "HLTHCHRT" (health chart). In this case there is no playing entity, and an optional scoping organization (Organization class).

Represents a participant who has legally authenticated the document.

The CDA is a standard that specifies the structure of exchanged clinical documents. In the case where a local document is transformed into a CDA document for exchange, authentication occurs on the local document, and that fact is reflected in the exchanged CDA document. A CDA document can reflect the unauthenticated, authenticated, or legally authenticated state. The unauthenticated state exists when no authentication information has been recorded (i.e., it is the absence of being either authenticated or legally authenticated).

While electronic signatures are not captured in a CDA document, both authentication and legal authentication require that a document has been signed manually or electronically by the responsible individual. A legalAuthenticator has a required legalAuthenticator.time indicating the time of authentication, and a required legalAuthenticator.signatureCode, indicating that a signature has been obtained and is on file.

A legalAuthenticator is a person in the role of an assigned entity (AssignedEntity class). An assigned entity is a person assigned to the role by the scoping organization. The entity playing the role is a person (Person class). The entity scoping the role is an organization (Organization class).

Used to represent other participants not explicitly mentioned by other classes, that were somehow involved in the documented acts.

A participant is a person or organization in the role of a participating entity (AssociatedEntity class). The entity playing the role is a person (Person class). The entity scoping the role is an organization (Organization class).

When the participating entity is an organization, this is reflected by the presence of a scoping Organization, without a playing entity.

See ServiceEvent for a description of the performer participant.

The recordTarget represents the medical record that this document belongs to.

A clinical document typically has exactly one recordTarget participant. In the uncommon case where a clinical document (such as a group encounter note) is placed into more than one patient chart, more than one recordTarget participants can be stated.

The recordTarget(s) of a document are stated in the header and propagate to nested content, where they cannot be overridden (see See CDA Context).

A recordTarget is represented as a relationship between a person and an organization, where the person is in a patient role (PatientRole class). The entity playing the role is a patient (Patient class). The entity scoping the role is an organization (Organization class). A patient is uniquely identified via the PatientRole.id attribute.

CDA Release One allowed for additional person identifiers, corresponding to the Patient.id attribute in CDA Release Two. This attribute is included for backwards compatibility and has been deprecated because having two different ways to identify a patient can result in inconsistent usage. Further use of Patient.id is discouraged.

A patient's language communication skills can be expressed in the associated LanguageCommunication class. A Patient's birthplace is represented as a relationship between a patient and a place. The Birthplace class is played by a place (Place class), and scoped by the patient (Patient class).

A patient's guardian is a person or organization in the role of guardian (Guardian class). The entity playing the role of guardian is a person (Person class) or organization (Organization class). The entity scoping the role is the patient (Patient class).

Where a guardian is not explicitly stated, the value should default to local business practice (e.g. the patient makes their own health care decisions unless incapacitated in which case healthcare decisions are made by the patient's spouse).

See EncompassingEncounter for a description of the responsibleParty participant.

Several CDA Header participations can be played by the same person. In such cases, the person should be identified as the player for each appropriate participation. For instance, if a person is both the author and the authenticator of a document, the CDA Header should identify that person as both the author participant and the authenticator participant.

On other occasions, CDA Header participants are played by different people. The following table shows a number of scenarios and the values for various participants.

* Note that the ability of one clinician to co-sign or to sign on behalf of another clinician is subject to regulatory and local practice constraints.

The ParentDocument represents the source of a document revision, addenda, or transformation. ParentDocument.text is modeled as an ED data type - allowing for the expression of the MIME type of the parent document. It is not to be used to embed the related document, and thus ParentDocument.text.BIN is precluded from use.

Allowable values for the intervening relatedDocument.typeCode are shown in the following table.

A conformant CDA document can have a single relatedDocument with typeCode "APND"; a single relatedDocument with typeCode "RPLC"; a single relatedDocument with typeCode "XFRM"; a combination of two relatedDocuments with typeCodes "XFRM" and "RPLC"; or a combination of two relatedDocuments with typeCodes "XFRM" and "APND". No other combinations are allowed.

Document Identification, Revisions, and Addenda

A clinical document can be replaced by a new document and/or appended with an addendum.

A replacement document is a new version of the parent document. The parent document is considered superseded, but a system may retain it for historical or auditing purposes. The parent document being replaced is referenced via act relationship relatedDocument, where relatedDocument.typeCode is set to equal "RPLC" (for "replaces"). An example is a report found to contain an error that is subsequently replaced by the corrected report.

An addendum is a separate document that references the parent document, and may extend or alter the observations in the prior document. The parent document remains a current component of the patient record, and the addendum and its parent are both read by report recipients. The parent report (represented by the ParentDocument class) being appended is referenced via act relationship relatedDocument, where relatedDocument.typeCode is set to equal "APND" (for "appends").

Every CDA document must have a unique ClinicalDocument.id, and thus the replacement or addendum documents each have ClinicalDocument.id that is different from that of the parent document.

CDA documents may also contain a ClinicalDocument.setId and a ClinicalDocument.versionNumber, which together support a document identification and versioning scheme used in some document management systems. In this scheme, all documents in a chain of replacements have the same ClinicalDocument.setId and are distinguished by an incrementing ClinicalDocument.versionNumber. The initial version of a document gets, in addition to a new unique value for ClinicalDocument.id, a new value for ClinicalDocument.setId, and has the value of ClinicalDocument.versionNumber set to equal "1". A replacement document gets a new globally unique ClinicalDocument.id value, and uses the same value for ClinicalDocument.setId as the parent report being replaced, and increments the value of ClinicalDocument.versionNumber by 1. (Note that version number must be incremented by one when a report is replaced, but can also be incremented more often to meet local requirements.)

These relationships are illustrated in the following exhibit "Document Identification, Revisions, and Addenda Scenarios". Typical scenarios are a simple relacement (e.g. ClinicalDocument.id "1.2.345.6789.266" replacing ClinicalDocument.id "1.2.345.6789.123") and a simple append (e.g. ClinicalDocument.id "1.2.345.6789.456" appends ClinicalDocument.id "1.2.345.6789.123"). More complex scenarios that might be anticipated include: [1] replacement of an addendum (e.g. ClinicalDocument.id "1.2.345.6789.224" replaces ClinicalDocument.id "1.2.345.6789.456", which itself is an addendum to ClinicalDocument.id "1.2.345.6789.123") - expected behavior would be to render the replacement as the addendum (e.g. render ClinicalDocument.id "1.2.345.6789.224" as the addendum to ClinicalDocument.id "1.2.345.6789.123"); [2] addendum to a replaced document (e.g. ClinicalDocument.id "1.2.345.6789.456" appends ClinicalDocument.id "1.2.345.6789.123", which has been replaced by ClinicalDocument.id "1.2.345.6789.266") - expected behavior would be to render the addendum along with the replacement (e.g. render ClinicalDocument.id "1.2.345.6789.456" as an addendum to ClinicalDocument.id "1.2.345.6789.266").

Document transformations

A CDA document can be a transformation from some other format, meaning that it has undergone a machine translation from some other format (such as DICOM SR). In this case, relatedDocument.typeCode should be set to "XFRM".

A proper transformation must ensure that the human readable clinical content of the report is not impacted. Local business rules determine whether or not a transformed report replaces the source, but typically this would not be the case. If it is, an additional relationship of type "RPLC" is to be used. The "XFRM" relationship can also be used when translating a document in a local format into CDA for the purpose of exchange. In this case, the target of the "XFRM" relationship is the local document identifier.

This class represents the main Act, such as a colonoscopy or an appendectomy, being documented.

In some cases, the ServiceEvent is inherent in the ClinicalDocument.code, such as where ClinicalDocument.code is "History and Physical Report" and the procedure being documented is a "History and Physical" act. A ServiceEvent can further specialize the act inherent in the ClinicalDocument.code, such as where the ClinicalDocument.code is simply "Procedure Report" and the procedure was a "colonoscopy". If ServiceEvent is included, it must be equivalent to or further specialize the value inherent in the ClinicalDocument.code, and shall not conflict with the value inherent in the ClinicalDocument.code, as such a conflict would constitute an ambiguous situation.

ServiceEvent.effectiveTime can be used to indicate the time the actual event (as opposed to the encounter surrounding the event) took place.

The performer participant represents clinicians who actually and principally carry out the ServiceEvent. Performer.time can be used to specify the time during which the performer is involved in the activity. Performer.functionCode can be used to specify addition detail about the function of the performer (e.g. scrub nurse, third assistant). Its value set is drawn from the ParticipationFunction vocabulary domain, and has a CWE coding strength.

A performer is an entity in the role of assigned entity (AssignedEntity class). An assigned entity is a person assigned to the role by the scoping organization. The entity playing the role is a person (Person class). The entity scoping the role is an organization (Organization class).

This class represents those orders that are fulfilled by this document. For instance, a provider orders an X-Ray. The X-Ray is performed. A radiologist reads the X-Ray and generates a report. The X-Ray order identifier is transmitted in the Order class, the performed X-Ray procedure is transmitted in the ServiceEvent class, and the ClinicalDocument.code would be valued with "Diagnostic Imaging Report".

This class references the consents associated with this document. The type of consent (e.g. a consent to perform the related ServiceEvent, a consent for the information contained in the document to be released to a third party) is conveyed in Consent.code. Consents referenced in the CDA Header have been finalized (Consent.statusCode must equal "completed") and should be on file.

This optional class represents the setting of the clinical encounter during which the documented act(s) or ServiceEvent occurred. Documents are not necessarily generated during an encounter, such as when a clinician, in response to an abnormal lab result, attempts to contact the patient but can't, and writes a Progress Note.

In some cases, the setting of the encounter is inherent in the ClinicalDocument.code, such as where ClinicalDocument.code is "Diabetes Clinic Progress Note". The setting of an encounter can also be transmitted in the HealthCareFacility.code attribute. If HealthCareFacility.code is sent, it should be equivalent to or further specialize the value inherent in the ClinicalDocument.code (such as where the ClinicalDocument.code is simply "Clinic Progress Note" and the value of HealthCareFacility.code is "cardiology clinic"), and shall not conflict with the value inherent in the ClinicalDocument.code, as such a conflict would constitute an ambiguous situation.

EncompassingEncounter.dischargeDispositionCode can be used to depict the disposition of the patient at the time of hospital discharge (e.g., discharged to home, expired, against medical advice, etc.).

The location participant (location class) relates a healthcare facility (HealthCareFacility class) to the encounter to indicate where the encounter took place. The entity playing the role of HealthCareFacility is a place (Place class). The entity scoping the HealthCareFacility role is an organization (Organization class).

The setting of an encounter (e.g. cardiology clinic, primary care clinic, rehabilitation hospital, skilled nursing facility) can be expressed in HealthCareFacility.code. Note that setting and physical location are not the same. There is a many-to-many relationship between setting and the physical location where care is delivered. Thus, a particular room can provide the location for cardiology clinic one day, and for primary care clinic another day; and cardiology clinic today might be held in one physical location, but in another physical location tomorrow.

When the location is an organization, this is indicated by the presence of a scoping Organization, without a playing Place.

The responsibleParty participant represents the participant having primary legal responsibility for the encounter. This differs from the legalAuthenticator participant in that the legalAuthenticator may or may not be the responsible party, and is serving a medical records function by signing off on the document, moving it into a completed state.

A responsibleParty is a person or organization in the role of an assigned entity (AssignedEntity class). An assigned entity is a person assigned to the role by the scoping organization. The entity playing the role is a person (Person class). The entity scoping the role is an organization (Organization class).

When the responsible party is an organization, the value for AssignedEntity.classCode is "ASSIGNED", and the responsible party is reflected by the presence of a scoping Organization, without a playing entity.

The encounterParticipant participant represents clinicians directly associated with the encounter (e.g. by initiating, terminating, or overseeing it).

An encounterParticipant is an entity in the role of assigned entity (AssignedEntity class). An assigned entity is a person assigned to the role by the scoping organization. The entity playing the role is a person (Person class). The entity scoping the role is an organization (Organization class).

The NonXMLBody class represents a document body that is in some format other than XML. NonXMLBody.text is used to reference data that is stored externally to the CDA document or to encode the data directly inline.

Rendering a referenced non-XML body requires a software tool that recognizes the particular MIME media type of the blob.

* The codeSystem value is included here because confidentialityCode is of type CE, and therefore must carry both a code and a codeSystem.

The StructuredBody class represents a CDA document body that is comprised of one or more document sections.

* The codeSystem value is included here because confidentialityCode is of type CE, and therefore must carry both a code and a codeSystem.

The StructuredBody class is associated with one or more Section classes through a component relationship.

The unique instance identifier of a particular document section.

The code specifying the particular kind of section (e.g. Chief Complaint, Review of Systems, Assessment). The value set is drawn from LOINC, and has a CWE coding strength.

Represents the label of a section. If valued, it is to be rendered as part of the narrative content of the clinical document body.

Used to store narrative to be rendered. Also referred to as the CDA Narrative Block. See Section Narrative Block for details.

A value for Section.confidentialityCode overrides the value propagated from StructuredBody. See CDA Context for more details.

* The codeSystem value is included here because confidentialityCode is of type CE, and therefore must carry both a code and a codeSystem.

Specifies the human language of character data (whether they be in contents or attribute values). The values of the attribute are language identifiers as defined by the IETF (Internet Engineering Task Force) RFC 3066: Tags for the Identification of Languages, ed. H. Alvestrand. 1995 , which obsoletes RFC 1766. The HL7 code system for these values is "2.16.840.1.113883.6.121".

A value for Section.languageCode overrides the value propagated from StructuredBody. See CDA Context for more details.

The author participant (described above, see author), can be ascribed to a CDA section, where it overrides the value(s) propagated from the CDA header.

The informant participant (described above, see informant), can be ascribed to a CDA section where it overrides the value(s) propagated from the CDA header.

The subject participant represents the primary target of the entries recorded in the document. Most of the time the subject is the same as the recordTarget (see recordTarget), but need not be, for instance when the subject is a fetus observed in an obstetrical ultrasound.

The subject participant can be ascribed to a CDA section or a CDA entry. It propagates to nested components, unless overridden. The subject of a document is presumed to be the patient.

A subject is a person playing one of several possible roles (RelatedSubject class). The entity playing the role is a person (SubjectPerson class).

The "component" Act Relationship is used to nest a Section within a Section. Context propagates to nested sections (see CDA Context).

The relationship between a section and its entries is encoded in the intervening "entry" Act Relationship.

Note: See Referencing in and out of the narrative block for a discussion of referencing in and out of a section's narrative block.

The narrative of each Section, together with the multimedia content referenced in the narrative, comprises the complete authenticated content of the Section. This multimedia content consists of ObservationMedia and RegionOfInterest entries referenced by <renderMultimedia> tags in the Section.text. This is the only case where the entries contain authenticated content that must be rendered with the narrative.

In terms of the relationship between a section and its entries, CDA defines a default general case, and a more specific case that can be used when applicable.

The entry relationship is defaulted to "COMP" (component), for the general case where the only assertion is that the related entries are contained within the source section and no other semantics are implied. In this case, the narrative is the original authenticated content. The CDA entries are created by various techniques (e.g., natural language processing, a human coder, a structured data entry tool that outputs both entries and a text report). The method of entry creation may be indicated by the entry participants (e.g., by identifying the algorithm or person that generated them). Relationships between various entries (such as two Observations or an Observation and an ObservationMedia) are encoded using the relationship types defined in entryRelationship.

A section may also have no narrative content in the case where the entries represent information that is not part of the clinical content of the document. A report may embed information referencing evidence data, reagents, calibration or other information that may be used for later processing but is not part of the clinical content. Such entries are also linked to the Section with ActRelationships possessing typeCode="COMP".

The entry relationship "DRIV" (is derived from) can be used in the special case where the narrative is fully derived from CDA Entries. When a report consisting entirely of structured entries is transformed into CDA, the encoding application must ensure that the authenticated content (narrative plus multimedia) is a faithful and complete rendering of the clinical content of the structured source data. This ensures that the narrative plus multimedia represents, as in all CDA documents, the complete authenticated content of the Section. In this case, narrative plus multimedia does not contain any clinical content that is not present in the Entries. An example of this case is a DICOM Structured Reporting document of obstetrical measurements made by ultrasound, rendered into a tabular report by a program converting it to CDA narrative block. If the typeCode of the ActRelationship linking these Entries to the Section was "DRIV", it would indicate to a receiving application: 1) the source of the narrative block is the Entries; 2) the contents of the two are equivalent.

The entries sourced from a Section may have a mix of ActRelationship typeCodes. In such a case, the union of the targets with a "DRIV" relationship are those used to generate the narrative block, and are those that, taken in total, are equivalent to the narrative block. Additional entries with "COMP" relationships are contained within the same section, with no implied semantics.

The CDA <content> element is used to wrap a string of text so that it can be explicitly referenced, or so that it can suggest rendering characteristics. The <content> element can nest recursively, which enables wrapping a string of plain text down to as small a chunk as desired.

The <content> element contains an optional identifier, that can serve as the target of a reference. All values of attributes of type XML ID must be unique within the document (per the W3C XML specification). The originalText component of a RIM attribute present in any CDA entry can make explicit reference to the identifier, thereby indicating the original text associated with the attribute in the CDA entry.

<section>
   <code code="10153-2" 
    codeSystem="2.16.840.1.113883.6.1" 
    codeSystemName="LOINC"/>
   <title>Past Medical History</title>
   <text>
    There is a history of <content ID="a1">Asthma</content>
   </text>
   <entry>
      <observation classCode="OBS" moodCode="EVN">
         <code code="195967001" 
          codeSystem="2.16.840.1.113883.6.96" 
          codeSystemName="SNOMED CT" 
          displayName="Asthma">
            <originalText>
               <reference value="#a1"/>
            </originalText>
         </code>
         <statusCode code="completed"/>
      </observation>
   </entry>
</section>

There is no requirement that CDA entries must reference into the CDA Narrative Block. The referencing mechanism can be used where it is important to represent the original text component of a coded CDA entry.

The <content> element contains an optional "revised" attribute that can be valued with "insert" or "delete", which can be used to indicate narrative changes from the last version of a CDA document. The attribute is limited to a single generation, in that it only reflects the changes from the preceding version of a document. If applied, it needs to be used in conjunction with standard CDA revision tracking. Changes to a CDA document that has been released for patient care still require a formal versioning and revision, and the revised document can optionally carry the "revised" attribute to show the delta in the narrative. Receivers are required to interpret the "revised" attribute when rendering by visually distinguishing or suppressing deleted narrative.

The CDA <linkHtml> is a generic referencing mechanism, similar, but not identical, to the HTML anchor tag. It can be used to reference identifiers that are either internal or external to the document.

Multimedia that is integral to a document, and part of the attestable content of the document requires the use of the ObservationMedia CDA entry, which is referenced by the <renderMultiMedia> element (see <renderMultiMedia>). Multimedia that is simply referenced by the document and not an integral part of the document can use <linkHtml>.

The source of a link uses the linkHtml.href attribute. The target of an internal reference is an identifier of type XML ID, which can exist on other elements in the same or a different narrative block, or XML ID attributes that have been added to the <section>, <ObservationMedia>, or <renderMultiMedia> elements of the CDA Schema. The linkHtml.name attribute is deprecated, because attributes of type XML ID provide an alternative and more consistent target for referencing. Following the conventions of HTML, an internal link is prefaced with the pound sign, as shown in the following example.

<section ID="SECT001">
   <code code="10164-2" codeSystem="2.16.840.1.113883.6.1" 
    codeSystemName="LOINC"/>
   <title>History of Present Illness</title>
   <text>Mr. Smith is a 57 year old male presenting with 
    chest pain. He sustained a myocardial infarction 3 years 
    ago, ...
   </text>
</section>

...

<section ID="SECT003">
   <code code="10153-2" codeSystem="2.16.840.1.113883.6.1" 
    codeSystemName="LOINC"/>
   <title>Past Medical History</title>
   <text>History of coronary artery disease, as noted
    <linkHtml href="#SECT001">above</linkHtml>.</text>
</section>

CDA links do not convey shareable meaning. Shareable semantics are only achieved by the inclusion of CDA entries and their associated formalized relationships. There is no requirement that a receiver render an internal or external link, or the target of an external link.

The CDA <sub> and <sup> elements are used to indicate subscripts and superscripts, respectively.

Receivers are required to interpret these elements when rendering by visually distinguishing subscripted and superscripted characters.

The CDA <br/> element is used to indicate a hard line break. It differs from the CDA <paragraph> element in that the <br/> element has no content. Receivers are required to interpret this element when rendering so as to represent a line break.

The CDA <footnote> element is used to indicate a footnote. The element contains the footnote, inline with the flow of text to which it is applied.

The <footnoteRef> element can reference an existing footnote in the same or different CDA Narrative Block of the same document. It can be used when the same footnote is being used multiple times. The value of the footnoteRef.IDREF must be an footnote.ID value in the same document.

Receivers are required to interpret these elements when rendering by visually distinguishing footnoted text. The exact rendition is at the discretion of the recipient, and might include a mark at the location of the footnote with a hyperlink to the footnoted text, a simple demarcation (such as "This is the text [this is the footnote] that is being footnoted"), etc.

The CDA <renderMultiMedia> element references external multimedia that is integral to a document, and part of the attestable content of the document, and serves to show where the referenced multimedia is to be rendered.

The <renderMultiMedia> element has an optional <caption>, and contains a required referencedObject attribute (of type XML IDREFS), the values of which must equal the XML ID value(s) of ObservationMedia or RegionOfInterest CDA entries within the same document.

<section>
   <code code="8709-8" codeSystem="2.16.840.1.113883.6.1" 
    codeSystemName="LOINC"/>
   <title>Skin exam</title>
   <text>Erythematous rash, palmar surface, left index 
    finger.<renderMultiMedia referencedObject="MM1"/>
   </text>
   <entry>
      <observationMedia classCode="OBS" moodCode="EVN" ID="MM1">
         <id root="2.16.840.1.113883.19.2.1"/>
         <value xsi:type="ED" mediaType="image/jpeg">
            <reference value="left_hand_image.jpeg"/>
         </value>
      </observationMedia>
   </entry>
</section>

Multimedia that is simply referenced by the document and not an integral part of the document must use <linkHtml>.

The expected behavior is that the referenced multimedia should be rendered or referenced at the point of reference. Where a caption is present, it must also be rendered. <renderMultiMedia> can either reference a single ObservationMedia, or one or more RegionOfInterest. If <renderMultiMedia> references a single ObservationMedia, that ObservationMedia should be rendered or referenced at the point of reference. If <renderMultiMedia> references one or more RegionOfInterest, all RegionOfInterests should be rendered or referenced at the point of reference, atop the multimedia they are regions of. If <renderMultiMedia> references more than one RegionOfInterest, each RegionOfInterest must be a region on the same multimedia.

A CDA <paragraph> is similar to the HTML paragraph, which allows blocks of narrative to be broken up into logically consistent structures. A CDA <paragraph> element contains an optional caption, which if present must come first before any other character data.

A CDA <list> is similar to the HTML list. A CDA <list> has an optional caption, and contains one or more <item> elements. A CDA <item> element contains an optional caption, which if present must come first before any other character data. The required listType attribute specifies whether the <list> is ordered or unordered (with unordered being the default). Unordered lists are typically rendered with bullets, whereas ordered lists are typically rendered with numbers, although this is not a requirement.

The CDA <table> is similar to the HTML table. The table markup is for presentation purposes only and, unlike a database table, does not possess meaningful field names.

CDA modifies the strict XHTML table model by removing formatting tags and by setting the content model of cells to be similar to the contents of other elements in the CDA Narrative Block.

The table.border, table.cellspacing, and table.cellpadding attributes are deprecated, because the styleCode attribute (see styleCode attribute provides a more consistent way for senders to suggest rendering characteristics.

The CDA <caption> is a label for a paragraph, list, list item, table, or table cell. It can also be used within the <renderMultiMedia> element to indicate a label for referenced ObservationMedia and RegionOfInterest entries. A <caption> contains plain text and may contain links and footnotes.

The styleCode attribute is used within the CDA Narrative Block to give the instance author the ability to suggest rendering characteristics of the nested character data. Receivers are not required to render documents using the style hints provided and can present stylized text in accordance with their local style conventions.

The value set is drawn from the HL7 styleType vocabulary domain, and has a CWE coding strength.

Local extensions to the styleType vocabulary domain must follow the following convention: [x][A-Za-z][A-Za-z0-9]* (first character is "x", second character is an upper or lower case A-Z, remaining characters are any combination of upper and lower case letters or numbers).

The styleCode attribute can contain multiple values, separated by white space. Where an element containing a styleCode attribute is nested within another element containing a styleCode attribute, the style effects are additive, as in the following example:

<section>
   <text><content styleCode="Bold">This is rendered bold, 
    <content styleCode="Italics">this is rendered bold and 
    italicized,</content> this is rendered bold. </content>
    <content styleCode="Bold Italics">This is also rendered 
    bold and italicized.</content>
   </text>
</section>

Note: See entry for a discussion of the relationships between a section and its contained entries.

To summarize the mechanisms for referencing in and out of the CDA Narrative Block:

• CDA entries can point in to the <content> element of the CDA Narrative Block (see <content>).
• The <linkHtml> element of the CDA Narrative Block can reference targets that are either internal or external to the document (see <linkHtml>).
• The <footnoteRef> element of the CDA Narrative Block can reference a <footnote> element in the same or different CDA Narrative Block of the same document (see <footnote> and <footnoteRef>).
• The <renderMultiMedia> element of the CDA Narrative Block can point out to CDA ObservationMedia and RegionOfInterest entries of the same document (see <renderMultiMedia>).

A derivative of the RIM Act class, to be used when the other more specific classes aren't appropriate.

Act.negationInd, when set to "true", is a positive assertion that the Act as a whole is negated. Some properties such as Act.id, Act.moodCode, and the participations are not affected. These properties always have the same meaning: i.e., the author remains the author of the negative Act. An act statement with negationInd is still a statement about the specific fact described by the Act. For instance, a negated "finding of wheezing on July 1" means that the author positively denies that there was wheezing on July 1, and that he takes the same responsibility for such statement and the same requirement to have evidence for such statement than if he had not used negation.

A derivative of the RIM PatientEncounter class, used to represent related encounters, such as follow-up visits or referenced past encounters.

Note: The EncompassingEncounter class in the CDA Header (see Header Relationships) represents the setting of the clinical encounter during which the documented act occurred. The Encounter class in the CDA Body is used to represent other related encounters.

A derivative of the RIM Observation class, used for representing coded and other observations.

Observation.negationInd, when set to "true", is a positive assertion that the Observation as a whole is negated. Some properties such as Observation.id, Observation.moodCode, and the participations are not negated. These properties always have the same meaning: i.e., the author remains the author of the negative Observation. An observation statement with negationInd is still a statement about the specific fact described by the Observation. For instance, a negated "finding of wheezing on July 1" means that the author positively denies that there was wheezing on July 1, and that he takes the same responsibility for such statement and the same requirement to have evidence for such statement than if he had not used negation.

An Observation can have zero to many referenceRange relationships, which relate an Observation to the ObservationRange class, where the expected range of values for a particular observation can be specified.

A derivative of the RIM Observation class that represents multimedia that is logically part of the current document. This class is only for multimedia that is logically part of the attested content of the document. Rendering a referenced ObservationMedia requires a software tool that recognizes the particular MIME media type.

An XML attribute "ID" of type XML ID, is added to ObservationMedia within the CDA Schema. This attribute serves as the target of a <renderMultiMedia> reference (see <renderMultiMedia>). All values of attributes of type XML ID must be unique within the document (per the W3C XML specification).

The distinction between ObservationMedia and ExternalObservation is that ObservationMedia entries are part of the attested content of the document whereas ExternalObservations are not. For instance, when a clinician draws a picture as part of a progress note, that picture is represented as a CDA ObservationMedia. If that clinician is also describing a finding seen on a chest-x-ray, the referenced chest-x-ray is represented as a CDA ExternalObservation.

A derivative of the RIM Act class, which can be used to create arbitrary groupings of other CDA entries that share a common context. An Organizer can contain other Organizers and/or other CDA entries, by traversing the component relationship. An Organizer can refer to external acts by traversing the reference relationship. An Organizer cannot be the source of an entryRelationship relationship.

Note: CDA entries such as Observation can also contain other CDA entries by traversing the entryRelationship class. There is no requirement that the Organizer entry be used in order to group CDA entries.

A derivative of the RIM Procedure class, used for representing procedures.

Procedure.negationInd, when set to "true", is a positive assertion that the Procedure as a whole is negated. Some properties such as Procedure.id, Procedure.moodCode, and the participations are not affected. These properties always have the same meaning: i.e., the author remains the author of the negative Procedure. A procedure statement with negationInd is still a statement about the specific fact described by the Procedure. For instance, a negated "appendectomy performed" means that the author positively denies that there was ever an appendectomy performed, and that he takes the same responsibility for such statement and the same requirement to have evidence for such statement than if he had not used negation.

A derivative of the RIM Observation class that represents a region of interest on an image, using an overlay shape. RegionOfInterest is used to make reference to specific regions in images, e.g., to specify the site of a physical finding by "circling" a region in a schematic picture of a human body. The units of the coordinate values in RegionOfInterest.value are in pixels, expressed as a list of integers. The origin is in the upper left hand corner, with positive X values going to the right and positive Y values going down. The relationship between a RegionOfInterest and its referenced ObservationMedia or ExternalObservation is specified by traversing the entryRelationship or reference class, respectively, where typeCode equals "SUBJ". A RegionOfInterest must reference exactly one ObservationMedia or one ExternalObservation. If the RegionOfInterest is the target of a <renderMultimedia> reference, then it shall only reference an ObservationMedia and not an ExternalObservation.

An XML attribute "ID" of type XML ID, is added to RegionOfInterest within the CDA Schema. This attribute serves as the target of a <renderMultiMedia> reference (see <renderMultiMedia>). All values of attributes of type XML ID must be unique within the document (per the W3C XML specification).

The following example illustrates one sample use of RegionOfInterest. In this case, the clinician has identified a rash upon physical examination of the skin, and indicates this by creating a region of interest atop a hand image taken from an image library. The narrative block references the RegionOfInterest via the <renderMultiMedia> tag, and the referenced RegionOfInterest references the hand image.

<section>
   <code code="8709-8" codeSystem="2.16.840.1.113883.6.1" 
    codeSystemName="LOINC"/>
   <title>Skin Exam</title>
   <text>Erythematous rash, palmar surface, left index 
    finger.<renderMultiMedia referencedObject="MM2"/>
   </text>
   <entry>
      <observation classCode="OBS" moodCode="EVN">
         <code code="271807003" 
          codeSystem="2.16.840.1.113883.6.96" 
          codeSystemName="SNOMED CT" 
          displayName="Rash"/>
         <statusCode code="completed"/>
         <targetSiteCode code="48856004" 
          codeSystem="2.16.840.1.113883.6.96" 
          codeSystemName="SNOMED CT" 
          displayName="Skin of palmer surface of index finger">
            <qualifier>
               <name code="78615007" 
                codeSystem="2.16.840.1.113883.6.96" 
                displayName="with laterality"/>
               <value code="7771000" 
                codeSystem="2.16.840.1.113883.6.96" 
                displayName="left"/>
            </qualifier>
         </targetSiteCode>
         <entryRelationship typeCode="SPRT">
            <regionOfInterest classCode="ROIOVL" moodCode="EVN" ID="MM2">
               <id root="2.16.840.1.113883.19.3.1"/>
               <code code="ELLIPSE"/>
               <value value="3"/>
               <value value="1"/>
               <value value="3"/>
               <value value="7"/>
               <value value="2"/>
               <value value="4"/>
               <value value="4"/>
               <value value="4"/>
               <entryRelationship typeCode="SUBJ">
                  <observationMedia classCode="OBS" moodCode="EVN">
                     <id root="2.16.840.1.113883.19.2.1"/>
                     <value mediaType="image/jpeg">
                        <reference value="lefthand.jpeg"/>
                     </value>
                  </observationMedia>
               </entryRelationship>
            </regionOfInterest>
         </entryRelationship>
      </observation>
   </entry>
</section>

A derivative of the RIM SubstanceAdministration class, used for representing medication-related events such as medication history or planned medication administration orders.

SubstanceAdministration.negationInd, when set to "true", is a positive assertion that the SubstanceAdministration as a whole is negated. Some properties such as SubstanceAdministration.id, SubstanceAdministration.moodCode, and the participations are not affected. These properties always have the same meaning: i.e., the author remains the author of the negative SubstanceAdministration. A substance administration statement with negationInd is still a statement about the specific fact described by the SubstanceAdministration. For instance, a negated "aspirin administration" means that the author positively denies that aspirin is being administered, and that he takes the same responsibility for such statement and the same requirement to have evidence for such statement than if he had not used negation.

SubstanceAdministration.priorityCode categorizes the priority of a substance administration. SubstanceAdministration.doseQuantity indicates how much medication is given per dose. SubstanceAdministration.rateQuantity can be used to indicate the rate at which the dose is to be administered (e.g., the flow rate for intravenous infusions). SubstanceAdministration.maxDoseQuantity is used to capture the maximum dose of the medication that can be given over a stated time interval (e.g., maximum daily dose of morphine, maximum lifetime dose of doxorubicin). SubstanceAdministration.effectiveTime is used to describe the timing of administration. It is modeled using the GTS data type to accommodate various dosing scenarios, as illustrated in the following example.

<section>
   <text>Take captopril 25mg PO every 12 hours, starting on 
    Jan 01, 2002, ending on Feb 01, 2002.
   </text>
   <entry>
      <substanceAdministration classCode="SBADM" moodCode="RQO">
         <effectiveTime xsi:type="IVL_TS">
            <low value="20020101"/>
            <high value="20020201"/>
         </effectiveTime>
         <effectiveTime xsi:type="PIVL_TS" operator="A">
            <period value="12" unit="h"/>
         </effectiveTime>
         <routeCode code="PO" 
          codeSystem="2.16.840.1.113883.5.112" 
          codeSystemName="RouteOfAdministration"/>
         <doseQuantity value="1"/>
         <consumable>
            <manufacturedProduct>
               <manufacturedLabeledDrug>
                  <code code="318821008" 
                   codeSystem="2.16.840.1.113883.6.96" 
                   codeSystemName="SNOMED CT" 
                   displayName="Captopril 25mg tablet"/>
               </manufacturedLabeledDrug>
            </manufacturedProduct>
         </consumable>
      </substanceAdministration>
   </entry>
</section>

The capture of medication-related information also involves the interrelationship of SubstanceAdministration with several other classes. The consumable participation is used to bring in the LabeledDrug or Material entity that describes the administered substance. The LabeledDrug class, which is an Entity class playing the Role of Manufactured Product, identifies the drug that is consumed in the substance administration. The medication is identified by means of the LabeledDrug.code or the LabeledDrug.name. The Material entity is used to identify non-drug administered substances such as vaccines and blood products.

A derivative of the RIM Supply class, used for representing the provision of a material by one entity to another.

The dispensed product is associated with the Supply act via a product participant, which connects to the same ManufacturedProduct role used for SubstanceAdministration.

The Supply class represents dispensing, whereas the SubstanceAdministration class represents administration. Prescriptions are complex activities that involve both an administration request to the patient (e.g. take digoxin 0.125mg by mouth once per day) and a supply request to the pharmacy (e.g. dispense 30 tablets, with 5 refills). This should be represented in CDA by a SubstanceAdministration entry that has a component Supply entry. The nested Supply entry can have Supply.independentInd set to "false" to signal that the Supply cannot stand alone, without it's containing SubstanceAdministration. The following example illustrates a prescription representation in CDA.

<section>
   <text>Digoxin 0.125mg, 1 PO qDay, #30, 5 refills.</text>
   <entry>
      <substanceAdministration classCode="SBADM" moodCode="RQO">
         <effectiveTime xsi:type="PIVL_TS">
            <period value="24" unit="h"/>
         </effectiveTime>
         <routeCode code="PO" 
          codeSystem="2.16.840.1.113883.5.112" 
          codeSystemName="RouteOfAdministration"/>
         <doseQuantity value="1"/>
         <consumable>
            <manufacturedProduct>
               <manufacturedLabeledDrug>
                  <code code="317896006" 
                   codeSystem="2.16.840.1.113883.6.96" 
                   codeSystemName="SNOMED CT" 
                   displayName="Digoxin 125micrograms tablet"/>
               </manufacturedLabeledDrug>
            </manufacturedProduct>
         </consumable>
         <entryRelationship typeCode="COMP">
            <supply classCode="SPLY" moodCode="RQO">
               <repeatNumber>
                  <low value="0"/>
                  <high value="5"/>
               </repeatNumber>
               <independentInd value="false"/>
               <quantity value="30"/>
            </supply>
         </entryRelationship>
      </substanceAdministration>
   </entry>
</section>

The author participant (described above, see author), can be ascribed to a CDA section where it overrides the value(s) propagated from the CDA header, or can be ascribed to a CDA entry, where it overrides the value(s) propagated from a CDA section and propagates to nested entries.

The consumable participant is described above (see Entry Acts).

The informant participant (described above, see informant), can be ascribed to a CDA section where it overrides the value(s) propagated from the CDA header, or can be ascribed to a CDA entry, where it overrides the value(s) propagated from a CDA section and propagates to nested entries.

Can be used to represent any other participant that cannot be represented with one of the more specific participants. The participant can be ascribed to a CDA entry, and propagates to nested CDA entries, unless overridden.

A participant is an entity playing one of several possible roles (ParticipantRole class). The entity playing the role is a device (Device class) or other entity (PlayingEntity class). The scoper is any entity (Entity class).

The performer is a person who carries out or will carry out a particular act. The performer need not be the principal responsible participant, e.g. a surgery resident operating under supervision of attending surgeon is a performer.

The product participant is described above (see Entry Acts).

A specimen is a part of some entity, typically the subject, that is the target of focused laboratory, radiology or other observations. In many clinical observations, such as physical examination of a patient, the patient is the subject of the observation, and there is no specimen. The specimen participant is only used when observations are made against some substance or object that is taken or derived from the subject.

The subject participant (described above, see subject), can be ascribed to a CDA section, or it can be ascribed to a CDA entry, where it overrides the value(s) propagated from a CDA section and propagates to nested entries.

The component relationship has a source of Organizer (see Organizer, and a target that is another CDA entry, and is used to create groupings of CDA entries within an Organizer.

The precondition class, derived from the ActRelationship class, is used along with the Criterion class to express a condition that must hold true before some over activity occurs.

The referenceRange relationship (described above, see Observation), has a source of Observation, and a target of ObservationRange.

CDA has identified and modeled various link and reference scenarios. These scenarios enable CDA entries to be semantically linked to entries that exist within the same document (by traversing the entryRelationship class) or to objects external to it (by traversing the reference class).

Note: The CDA specification permits any CDA entry to relate to any CDA entry using any of the following relationship types. In many cases, this would result in nonsensical relationships. The following table is a guideline for reasonable relationships between CDA entries, and is not a conformance constraint.

The entryRelationship.inversionInd can be set to "true" to indicate that the relationship should be interpreted as if the roles of the source and target entries were reversed. In the example in the table above, "treadmill test" RSON (has reason) "chest pain". Inverted, this would have "chest pain" as the source and "treadmill test" as the target: "chest pain" RSON (inverted) "treadmill test". Inversion can be useful when the current context is describing the target of an act relationship that needs to be related back to the source.

The entryRelationship.contextConductionInd differs from the otherwise common use of this attribute (see CDA Context) in that in all other cases where this attribute is used, the value is fixed at "true", whereas here the value is defaulted to "true", and can be changed to "false" when referencing an entry in the same document. Setting the context conduction to false when referencing an entry in the same document keeps clear the fact that the referenced object retains its original context.

CDA entries can reference external objects such as external images and prior reports. These external objects are not part of the authenticated document content. They contain sufficient attributes to enable an explicit reference rather than duplicating the entire referenced object. The CDA entry that wraps the external reference can be used to encode the specific portions of the external reference that are addressed in the narrative block.

Each object allows for an identifier and a code, and contains the RIM Act.text attribute, which can be used to store the URL and MIME type of the object. External objects always have a fixed moodCode of "EVN".

The reference class contains the attribute reference.seperatableInd, which indicates whether or not the source is intended to be interpreted independently of the target. The indicator cannot prevent an individual or application from separating the source and target, but indicates the author's desire and willingness to attest to the content of the source if separated from the target. Typically, where seperatableInd is "false", the exchanged package should include the target of the reference so that the recipient can render it.

A description of allowable reference.typeCode values are shown in the following table. As in the table above (CDA entryRelationship Types), the following table is a guideline for reasonable relationships between CDA entries and external objects, and is not a conformance constraint.

Target classes of the reference relationship include ExternalAct, ExternalDocument, ExternalObservation, and External Procedure.

ExternalAct is a derivative of the RIM Act class, to be used when the other more specific classes are not appropriate.

ExternalDocument is a derivative of the RIM Document class, used for representing external documents. ExternalDocument.text is modeled as an ED data type - allowing for the expression of the MIME type of the external document.

ExternalObservation is a derivative of the RIM Observation class, used for representing external coded and other observations.

ExternalProcedure is a derivative of the RIM Procedure class, used for representing external procedures.

(ancestor-or-self::*/author)[position()=last()]