Structured Document Architecture

(main entry to be created)

FAQ

CDA R2 using a non-XML ITS

• In how far is CDA R2 "abstract"? - In other words: if one were to attempt to apply a different ITS (assuming there was one, e.g. ASN.1 or CORBA), what would the "open issues list" look like?

There are 3 known issues:

• Structure of the Narrative Block
• IIref mechanism
• typeId and templateId

(CDA R2 Documentation) "Specific enhancements to the CDA Schema, above and beyond those defined in the HL7 V3 XML ITS, are described [..] in CDA XML Implementation (§ 6 )." Section 6 states: "The CDA Narrative Block, which is the XML content model of section.text, is manually crafted, as described above (see Section Narrative Block (§ 4.3.5 ))."

(Charlie McKay) The way that references between parts of the narrative block and the structured content are done in an XML specific way (reasonably enough because HL7 itself -as an standard- does not have an IIref mechanism agreed yet). This is the rationale for the schema edit: Add "ID" attribute, of type XML ID, to Section, ObservationMedia, RegionOfInterest

(Charlie McKay) Looking at the schema (CDA.ReleaseTwo.MembershipBallot01.Dec.2004.xsd) distributed with the ballot it includes a way of representing typeId that is different from the rest of this ballot schemas (where typeId is an element).

<xs:attribute name="typeIdRoot" type="xs:string" use="optional"/>
<xs:attribute name="typeIdExtension" type="xs:string" use="optional"/>   

These two line are ones that are not consistent with the way that the RIM has evolved since Dec 2004 (both typeId and templateId are elements in all current schemas:

• Replace all typeId attributes with:

<xs:attribute name="typeIdRoot" type="xs:string" use="optional"/> 
<xs:attribute name="typeIdExtension" type="xs:string" use="optional"/>

• Add templateId attribute to all elements that inherit from InfrastructureRoot:

<xs:attribute name="templateId" use="optional"> 
  <xs:simpleType> 
    <xs:list itemType="oid"/> 
  </xs:simpleType> 
</xs:attribute>