Policy on use of translationCode in V3 (ISO 21090) coded datatypes
Use of translationCode in the V3 (and CDA) Datatypes
In the San Antonio HL7 Working Group Meeting (January 2017), the Vocabulary WG and the Structured Documents WG had a joint session to discuss the best approach for populating translations of codes in a data element of type CD or any of its specializations that include translation (CO in datatypes r2, unconstrained CR, CE, and CV in datatypes r1). Hitherto, HL7 has been silent on implementation details, and the group sought to improve specificity and clarity of guidance for the use of this property. In all of the cases where there is a translation represented in the datatype, the datatype in question includes a property of type CD, which itself contains translation (DSET<CD> in r2, SET<CD> in r1). Each of the datatypes carries a code (a coded concept) in the 'Code' property of the datatype. The following points were agreed upon in the meeting, and it was recommended that these be documented in the Policy area here on the Wiki.
- The best available standard code system code SHALL be captured in the data element (e.g. when used in CDA in observation.value, Code will usually carry a code from SNOMED CT in the case of Meaningful Use observations)
- The originalText property MAY capture the text that the clinician captured or selected in the user interface of the system used in creating the data element instance
- A code that represents the meaning for the originalText drawn from custom interface terminologies or another code system according to agreement of the trading partners MAY be populated in translation.Code
- When a code is populated in translation.Code, it SHALL be more specific than the best available standard code system code
- A code populated in translation.Code SHALL NOT be broader than the code populated in the Code property
It was noted that there are other rules and guidance needed when there is a chain of translations (i.e. data element.translation.translation.translationCode), but the group declined to create additional policy until such a Use Case was better understood. It was also noted that the above rules should be used when the primary Code is a post-coordinated expression, but it is unclear what policy should be followed if a translation to part of the expression (only one of the expression coded components rather than the entire expression) needs to be expressed. This is also left unspecified until it is better understood.