The Section.text field is used to store narrative to be rendered, as described above in CDA Conformance (§ 1.3 ), and is therefore referred to as the CDA Narrative Block. The narrative schema defined for CDA R3 has been aligned with a subset of the elements found in HTML, in order to simplify content generation and presentation. One notable exception is the continued reliance on <footnote> and <footnoteRef>, which are typically not included in clinical notes, but were retained for backwards comparability and continued support of SPL.
The CDA Narrative Block schema can be found here.
The content model of the CDA Narrative Block schema is specially hand crafted to meet the requirements outlined above (see Human Readability and Rendering CDA Documents (§ 1.2.3 )). The schema is will be registered as a MIME type (text/x-hl7-text+xml-r2), which is the fixed media type for Section.text. Components of the schema are described in the sections that follow.
4.3.5.1 / <contentspan> - content wrapping
The CDA <contentspan> 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 <contentspan> element can nest recursively, which enables wrapping a string of plain text down to as small a chunk as desired.
The <contentspan> 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.
Example 5
<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 span IDid="a1">Asthma</contentspan>
</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.
4.3.5.2 / <linkHtmla> - anchor element
The CDA <linkHtmla> 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 a supporting reference to an ObservationMedia CDA entry, which is referenced by the <renderMultiMediaimg> narrative element (see <renderMultiMediaimg> (§ 4.3.5.6 7 )).
Multimedia that is simply referenced by the document and not an integral part of the attested document can use the <linkHtml<img> element without a corresponding reference to an ObservationMedia or RegionOfInterest CDA entry.
The source of a link uses the linkHtmla.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 attribute of type xs:ID attributes that have been added to the <section>, <ObservationMedia>, or <renderMultiMedia>any narrative elements of the CDA Narrative Schema providing an attribute of type xs:ID. The use of the linkHtmla.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.
Example 6
<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 a href="#SECT001">above</linkHtmla>.</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 anchor link, or the target of an external link.
4.3.5.3 / <sub> and <sup> - superscript & subscript
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.
4.3.5.4 / <br> - line break
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.
4.3.5.5 / <ins> and <del> - Deprecated
The CDA <ins> and <del> elements can be used to indicate narrative changes from the last version of a CDA document. The usage of the elements 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 <ins> and / or <del> elements to show the delta in the narrative. Receivers are required to interpret the <del> element when rendering by visually distinguishing or suppressing deleted narrative.
We proposal to deprecate the use of <ins> and <del> with this revision, as it is redundant with the normal versioning supported in the CDA header using the relatedDocument / parentDocument elements.
4.3.5.65 / <footnote> and <footnoteRef>
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.
Use Cases for footnote in clinical documents; have not been identified over the course of the CDA R2. As a result, the use of <footnote> and <footnoteRef> elements is deprecated in CDA R3.
Note: Implementation Guides are encouraged to prohibit the use of these two elements in CDA R3 Implementation Guides, in order to simply the processing requirements for narrative text.
4.3.5.6 7 / <renderMultiMediaimg> - multimedia references
The CDA <renderMultiMediaimg> element is used to references external multimedia. Direct references to external multimedia using <img> are not assumed to be integral to or attested in the document and maybe excluded in CDA document exchanges. Multimedia that is integral to a document, and part of the attestable content of the document, must therefore reference either a contained ObservationMedia or RegionOfInterest entry to flag the multimedia as attested and and serves to show where the referenced multimedia is to be rendered.
The <renderMultiMediaimg> element has an optional <caption>, and contains a required referencedObjectsrc attribute (of type XML IDREFSURI), the values of which must equal the XML ID value(s) of ObservationMedia or RegionOfInterest CDA entries within the same document when flagging the content as authenticated and integral to the documents interpretation. The <img> element also contains a required alt attribute that needs to specify the alternate text for an image.
Example 7
<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 img referencedObjectsrc="#MM1" alt="image of: left_hand_image.jpg" />
</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 can use <linkHtmlaimg> or <img>, but must not reference observationMedia or RegionOfInterest elements.
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. <renderMultiMediaimg> elements can either reference a single ObservationMedia, or one or morea single RegionOfInterest. If <renderMultiMedia> references a singleIn either case the multimedia ObservationMedia, that ObservationMedia should be rendered or referenced at the point of reference in the narrative text. 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 the <renderMultiMediaimg> needs to references more than one RegionOfInterest, each RegionOfInterest must be a region on the same multimedia and contained within a single Organizer element with a classCode =”GROUPER”. The <img> will then reference the Organizer entry.
4.3.5.7 8 / <paragraph> - paragraphs
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.
4.3.5.8 9 / <list>Various list types
4.3.5.9.1 / <ol> - ordered lists
A CDA <ol> is similar to the HTML order list element. The <ol> element will contain 1 or more <li> list item elements.
4.3.5.9.2 / <ul> - unordered lists
A CDA <ul> is similar to the HTML unordered list element. The <ul> element will contain 1 or more <li> list item elements.
4.3.5.9.3 / <dl> - definition lists
A CDA <dl> is similar to the HTML definition list element. The <dl> element will contain 1 or more <dt> definition items and/or <dd> item definitions. Together these elements can be used to construct lists of terms with definitions.
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.
4.3.5.9 10 / <table>
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 (§ 4.3.5.11 ) provides a more consistent way for senders to suggest rendering characteristics.
4.3.5.10 11 / <caption>
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. Captions required for other CDA narrative elements will need to be expressed as explicit narrative content with the document. E.g. <p>Caption Text</p> any other narrative element here.
4.3.5.1211 / styleCode attribute
The styleCode style 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 styles hints provided and can present stylized text in accordance with their local style conventions.
The CDA R3 style attribute values will be one or more cascading style sheet properties = value pairs, separated by semicolons, similar to HTML. E.g. style=”font-weight:bold;color:red” - for red bold text.
The value set is drawn from the HL7 styleType vocabulary domain, and has a CWE coding strength.
Table 89: Value set for styleCode (CWE)
Code / Definition
Font style (Defines font rendering characteristics.)
Bold / Render with a bold font.
Underline / Render with an underlines font.
Italics / Render italicized.
Emphasis / Render with some type of emphasis.
Table rule style (Defines table cell rendering characteristics.)
Lrule / Render cell with left-sided rule.
Rrule / Render cell with right-sided rule.
Toprule / Render cell with rule on top.
Botrule / Render cell with rule on bottom.
Ordered list style (Defines rendering characteristics for ordered lists.)
Arabic / List is ordered using Arabic numerals: 1, 2, 3.
LittleRoman / List is ordered using little Roman numerals: i, ii, iii.
BigRoman / List is ordered using big Roman numerals: I, II, III.
LittleAlpha / List is ordered using little alpha characters: a, b, c.
BigAlpha / List is ordered using big alpha characters: A, B, C.
Unordered list style (Defines rendering characteristics for unordered lists.)
Disc / List bullets are simple solid discs.
Circle / List bullets are hollow discs.
Square / List bullets are solid squares.
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:
Example 8
<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>
4.3.5.13 / Other CDA Elements & Attributes
The remaining elements and attributes used are modeled after the XHTML 1.0 Strict Schema. Conformant implementations will only use the elements listed below:
4.3.5.12 / Referencing in and out of the narrative block
NOTE: See entry (§ 4.3.4.2 ) 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 <contentspan> element of the CDA Narrative Block (see <contentspan> - content wrapping (§ 4.3.5.1 )).
- The <linkHtmla> - anchor element of the CDA Narrative Block can reference targets that are either internal or external to the document (see <linkHtmla> - anchor element (§ 4.3.5.2 )).
- 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> (§ 4.3.5.5 6 )).
- The <renderMultiMediaimg> -multimedia references element of the CDA Narrative Block can point out to CDA ObservationMedia and RegionOfInterest entries of the same document (see <renderMultiMediaimg> - multimedia references (§ 4.3.5.6 7 )).