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CDA TRANSFER OF CARE IMPLEMENTATION GUIDE:
DATA ELEMENT MAPPING GAPS
MEMO
DATE
January 21, 2013
TO
Terry O’Malley and Lawrence Garber
FROM
Bob Dolin, Gaye Dolin, Sarah Gaunt, Zabrina Gonzaga, Russ
Hamm, George Koromia, Mike Tushan
RE
Implementation Guide Development
Improving Massachusetts Post-Acute Care Transfers ("IMPACT")
Program
Massachusetts Health Information Exchange (MASS HIE) recognizes the need for a standard electronic
exchange to improve data flow for Massachusetts Long Term and Post-Acute Care (MASS LTPAC) facilities.
Lantana Consulting Group is developing a Clinical Document Architecture (CDA) implementation guide for
transfer of care data in a pilot electronic information exchange system. Analyzing gaps between data elements
currently used in the MASS LTPAC system and existing standard CDA templates is a critical step in the
implementation guide development. During the Improving Massachusetts Post-Acute Care Transfers
(IMPACT) project, the MASS LTPAC community identified approximately 450 high-priority data elements
that should be included in a transfer of care document. This memo summarizes the approach and the results
of mapping current IMPACT data elements to existing standard CDA templates.
Overview of CDA
The Health Level Seven (HL7) CDA is a widely adopted industry standard for the exchange of clinical
documents. It is a document markup standard that specifies the structure and semantics of a clinical
document (such as a discharge summary, progress note, or procedure report) for the purpose of exchange
between organizations. It can be transferred within a message or can exist independently, outside the
transferring message. CDA documents are encoded in Extensible Markup Language (XML).1
CDA documents derive their machine processable meaning from the HL7 Reference Information Model
(RIM) and use the HL7 Version 3 (V3) data types.2 The RIM and the V3 data types provide a powerful
mechanism for CDA to incorporate concepts from standard coding systems such as Systemized
Nomenclature of Medicine Clinical Terms (SNOMED CT)3 and Logical Observation Identifiers Names and
Codes (LOINC).4
1 Dolin
RH, Alschuler L, Boyer SL, Beebe C, Behlen FM, Biron PV, Shabo A. HL7 Clinical Document Architecture,
Release 2. J Am Med Inform Assoc. 2006;13:30–39.
2 Bakken S, Campbell KE, Cimino JJ, Huff SM, Hammond WE. Toward vocabulary domain specifications for Health
Level 7–coded data elements. J Am Med Inform Assoc. 2000;7:333–42.
3 SNOMED Clinical Terms. College of American Pathologists. http://www.snomed.org/.
4 Logical Observation Identifiers Names and Codes (LOINC). http://www.loinc.org/.
Templated CDA Approach
CDA Release 2 (R2) can be constrained by mechanisms defined in the “Refinement and Localization”5
section of the HL7 Version 3 Interoperability Standards. The mechanism most commonly used to constrain
CDA is referred to as “templated CDA”. In this approach, a library of modular CDA templates is
constructed; the templates can be reused across any number of CDA document types. Different kinds of
templates can be created. The most common are:

Document-level templates: These templates constrain fields in the CDA header, and define
containment relationships to CDA sections. For example, a History-and-Physical document-level
template might require that the patient’s name be present, and that the document contain a Physical
Exam section.

Section-level templates: These templates constrain fields in the CDA section, and define
containment relationships to CDA entries. For example, a Physical-exam section-level template
might require that the section/code be fixed to a particular LOINC code, and that the section
contain a Systolic Blood Pressure observation.

Entry-level templates: These templates constrain the CDA clinical statement model in accordance
with real world observations and acts. For example, a Systolic-blood-pressure entry-level template
defines how the CDA Observation class is constrained (how to populate observation/code, how to
populate observation/value, etc.) to represent the notion of a systolic blood pressure.
The CDA implementation guide for a transfer of care document will include templates that are applicable to
the MASS LTPAC use case. The templates used in the implementation guide assert their conformance to
other templates, known as parent templates, by referencing the parent’s templateId. The recipient of the CDA
document can then test for conformance against the CDA schema and the asserted templates.
Mapping and Gap Analysis
Gap analysis is a first step in developing a transfer of care CDA implementation guide. The approach is to
map the IMPACT data elements to corresponding templates contained in the Consolidated CDA6 (C-CDA)
and LTPAC Summary libraries.
This exercise revealed three categories of mapping precision:
1. Maps (Category 1): A mapped data element is one that maps exactly to an existing CDA template.
An example is the data element for a medication such as warfarin. Warfarin would be contained in
the Medication Section with its details represented in the C-CDA Medication Activity entry template.
This template also represents any additional details such as drug dosage, route, indication, and
administration information.
2. Partially Mapped (Category 2): A partially mapped data element is one that maps closely to an
existing template with the template requiring minor modifications to constitute an exact match.
Examples of minor modifications include specifying an observation code for a data element or
providing stronger guidance in a constraint verb to ensure standard electronic exchange of critical
information (e.g., the implementer is required to always send timing of next INR test).
HL7 Version 3 Standard: Refinement, Constraint and Localization, Release 2.
http://www.hl7.org/v3ballot/html/infrastructure/conformance/conformance.htm
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3. Gap (Category 3): A data element is identified as a gap if it requires the creation of a new template,
extensive modification of an existing template, or a new vocabulary value set (e.g., defining the value
set for patient advanced directive wishes). For example, IMPACT collects information on “Culturally
Sensitive Patient Care”. This section collects social history data on patient likes, dislikes, and religious
preferences. The current C-CDA Social History template is constrained to a fixed vocabulary that
does not include these data elements.
The IMPACT Transfer of Care Mapping spreadsheet (referred to in this document as the “mapping
spreadsheet”) provides the following information:


Mapping tab: The mapping of IMPACT data elements to CDA templates.
o
Column A: Unique ID— a hierarchical identifier for each IMPACT data element
o
Column B: IMPACT Data Element
o
Column C: Data Element Description (where necessary)
o
Column D: CDA Template—If a corresponding or similar CDA template has been
identified, this template is listed in this column. If no existing template is appropriate to the
IMPACT data element the column lists “Gap”.
o
Column E: Mapping Results—the mapping category for the data element as described above
ValueSets tab: Value sets for those data elements with identified needs.
Result Summary
Approximately 60% of the IMPACT data elements fell into Category 1 and fully map to templates in the
Consolidated CDA template library. 14% of data elements partially mapped to existing CDA templates but
require additional guidance and/or minor vocabulary definition for an implementer (Category 2). The
remaining 26% of data elements were in Category 3.
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Next Steps
CDA representation of Category 2 data elements will require additional guidance and/or minor vocabulary
definition for an implementer while Category 3 data elements require template design and creation of
vocabulary sets to represent clinical concepts present in the IMPACT data set. The implementation guide
development team will continue to analyze the data elements to find the appropriate representation for the
40% of the data elements that do not fully map to existing templates in the CDA library. These Category 2
and Category 3 data elements will be addressed through:

Tables with guidance on template patterns that communicate the IMPACT concepts

Guidance for communication of free text or original text information in specified instances
The next steps in the development and design of the Transfer of Care (TOC) Implementation Guide are:

Develop a CDA TOC sample file containing examples of mapped and partially mapped data
elements.

Include in the CDA TOC sample file sections (i.e. Medications, Allergies, etc.) needed for
development of the SEE implementation tool.

Create a CDA implementation guide document framework
The team will further analyze the data elements presented in this mapping update. Analysis will focus on
merging of like data elements and harmonizing with existing data sets such as CARE and INTERACT. The
team will continue to work with stakeholders to prioritize data elements and to determine duplication within
the data set during bi-monthly meetings for the Care Transition sub-workgroup of the S&I Framework
Longitudinal Coordination of Care (Mondays 11:00 am – 12:00 pm ET).
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