1. MDF99 Vocabulary Chapter HL7 Working Group Meetings April 26, 1999 Toronto, Canada Stan Huff - coshuff@ihc.com http://www.hl7.org

2. 3/18/19991© 1999, Health Level Seven, Inc. Message Development Framework Description of how to develop Version 3 Messages 1999 is the first time a vocabulary chapter has been included Focuses on processes and methods for producing ballotable Version 3 messages Complete draft document is available from the Duke web site Final 1999 document will be available by the last week of May

3. 3/18/19992© 1999, Health Level Seven, Inc. Outline of Vocabulary Chapter Vocabulary domains Structure of coded elements in messages The general process of maintaining domain specifications Good vocabulary practices Use of external terminologies in HL7 standards (Keith Campbell) The use of local vocabularies in coded elements HL7 vocabulary and the UMLS Metathesaurus

4. 3/18/19993© 1999, Health Level Seven, Inc. Vocabulary Domains Introduction Vocabulary Domains and Vocabulary Domain Specifications Vocabulary Domain Constraints –Rules for creating vocabulary domain constraints –The syntax for constraining vocabulary domains in MIMs, METs, CMETs, HMDs, and clinical templates Validating Vocabulary Domain Specifications and Constraints The Domain Specification Database

5. 3/18/19994© 1999, Health Level Seven, Inc. Introduction: Vocabulary domains Marital Status –single (never married) –married –divorced –separated Vocabulary to distinguish from Subject Domains in the RIM Why Vocabulary Domains? –Increase interoperability –Sharing of data (clinical care, outcomes, research) –Sharing of decision logic

6. 3/18/19995© 1999, Health Level Seven, Inc. Vocabulary domain The set of all concepts that can be taken as valid values in an instance of a coded field or attribute. Concept - A unit of thought constituted through abstraction on the basis of characteristics common to a set of objects. ISO 1087 Each concept in the domain can represented using a specific vocabulary/terminology

7. 3/18/19996© 1999, Health Level Seven, Inc. Each coded attribute has a domain specification Class: Patient Description: A person who may receive, is receiving, or has received healthcare services. Associations is_a_role_of (1,1) :: Person is_source_for (0,n) :: Specimen_sample Attributes birth_order_number birth_dttm (from Person) gender_cd

8. 3/18/19997© 1999, Health Level Seven, Inc. Vocabulary Domain Specification One for each coded RIM attribute General form: – Currently two types of domain qualifiers –Strength (StrengthOfCoding) CNE - Coded No Exceptions CWE - Coded With Exceptions –Realm (RealmOfUse) Universal USA? Europe? Others

9. 3/18/19998© 1999, Health Level Seven, Inc. Vocabulary Domain Constraint Used in MIM, MET, CMET, HMD, Clinical Templates Example: – General Form – Three forms for domain expression –Single domain (same as domain specification) –Single code (same as Code Value, V3 Data Type) –Set operation expression - Union - - Difference (sometimes represented as \) - Intersection

10. 3/18/19999© 1999, Health Level Seven, Inc. Validating Specifications and Constraints Validation can be time and resource intensive May want to do selective validiation –During testing and debugging –During conformance testing –During the creation of each message –During the decoding of each message –Only on some fields –Only when errors occur –Or all of the above

11. 3/18/199910© 1999, Health Level Seven, Inc. The domain specification database There can (and will) be improvements in the table design Requirements: (UML model not shown) –Unique, non-sense identifier –Unique textual name –Description/definition –Edit note –Version tracking –Can be specific to a realm of use –Each leaf set is from a single vocabulary –Domains can be recursively defined –Set notation will be used to describe relationships

12. 3/18/199911© 1999, Health Level Seven, Inc. Domain Specification Database Tables Composite Domain Definition Table Primitive Domain Definition Table Primitive Domain Enumeration Table LOINC to Domain Linking Table Version Tracking Table Edit Permissions Table

13. 3/18/199912© 1999, Health Level Seven, Inc. Composite Domain Definition Table

14. 3/18/199913© 1999, Health Level Seven, Inc. Composite Domain Definition Table (content)

15. 3/18/199914© 1999, Health Level Seven, Inc. Composite Domain Definition (version tracking)

16. 3/18/199915© 1999, Health Level Seven, Inc. Version Tracking Table

17. 3/18/199916© 1999, Health Level Seven, Inc. Primitive Domain Definition Table

18. 3/18/199917© 1999, Health Level Seven, Inc. Primitive Domain Enumeration Table

19. 3/18/199918© 1999, Health Level Seven, Inc. LOINC to Domain Linking Table

20. 3/18/199919© 1999, Health Level Seven, Inc. Using the Domain Specification Database Look in composite domain table –Use domain name and realm –Find domains in expression –Look up domains found in expression Look in primitive domain table –Use domain name or Id, and vocabulary –If Internal domain Resolve domain to individual elements in domain enumeration table –If External domain Resolve domain by calling a vocabulary server or by reference to externally maintained tables

21. 3/18/199920© 1999, Health Level Seven, Inc. Real World Concept Types Code Value Code Phrase Code Translation Concept Descriptor

22. 3/18/199921© 1999, Health Level Seven, Inc. Code Value (definition) value (Character String, conditional) code system (code, required) code system version (Character String, optional) print name (Character String, optional) replacement (Character String, conditional) Condition: An instance of a code value will contain either a value or a replacement, but not both.

23. 3/18/199922© 1999, Health Level Seven, Inc. Code Value (example 1) Patient Blood Type == Code Value { value F-D1111, code-system SMI -- from a table code-system-version 3.4 print-name Blood group A }

24. 3/18/199923© 1999, Health Level Seven, Inc. Code Value (example 2a) Patient Sex == Code Value { value M, code-system HL70001 code-system-version 3.0 print-name Male }

25. 3/18/199924© 1999, Health Level Seven, Inc. Code Value (example 2b) Tetanus Special Circumstances == Code Value { value 3, code-system DEEDS4.31 -- subpart needed? code-system-version 1.0 print-name only the year is known }

26. 3/18/199925© 1999, Health Level Seven, Inc. Code Value (example 3) Patient Sex == Code Value { code-system HL70001 code-system-version 3.0 replacement Male Pseudo-hermaphrodite } Desired value is not a member of the coding system

27. 3/18/199926© 1999, Health Level Seven, Inc. Code Value (incorrect 4) Patient Sex == Code Value { value MPH code-system HL70001 code-system-version 3.0 replacement Male Pseudo-hermaphrodite } Value and Replacement should not be present at the same time.

28. 3/18/199927© 1999, Health Level Seven, Inc. Code Value (example 5) Patient Blood Type == Code Value { value F-D1111, code-system SMI -- from a table } Code System Version and Print Name are not required.

29. 3/18/199928© 1999, Health Level Seven, Inc. Code Phrase (definition) ORDERED LIST OF Code Value

30. 3/18/199929© 1999, Health Level Seven, Inc. Code Phrase (example 1) Body Location == Code Phrase { { value R code-system 99Lab -- A Local coding system print-name right } { value ARM code-system 99Lab print-name arm } } Note that the roles (side, body part) of these items are not specified. Roles can be specified by making separate coded fields in a message.

31. 3/18/199930© 1999, Health Level Seven, Inc. Code Phrase (example 2) Body Location == Code Phrase { {value R code-system 99Lab -- A Local coding system print-name right } {code-system 99Lab replacement anterior axillary fold } } A Code Phrase can consist of a true code and a replacement code as part of the same ordered list.

32. 3/18/199931© 1999, Health Level Seven, Inc. Code Translation (definition) term (Code Phrase, required) origin (reference to Code Translation, required) producer (TII, optional) quality (floating point number, optional) label (Character String, optional) (Examples are shown with Concept Descriptor)

33. 3/18/199932© 1999, Health Level Seven, Inc. Concept Descriptor (definition) SET OF Code Translation (required) Original Text (Free Text, optional)

34. 3/18/199933© 1999, Health Level Seven, Inc. Go To Word Document

35. 3/18/199934© 1999, Health Level Seven, Inc. Local Vocabulary Use Can only be used with qualifier Strength:CWE The complete domain is a union of standard domain plus local concepts (as a union of the two) Rules –Local concept can not replace standard concept –Local code system names must start with 99 –Local codes should be submitted to HL7 for inclusion in standard domain and forwarded to terminology developers

36. 3/18/199935© 1999, Health Level Seven, Inc. General process of maintaining domains Follow pattern of RIM harmonization Vocabulary TC appoints facilitators Message development TCs have stewardship –Ultimate authority for domain contents –Follow RIM harmonization rules Vocabulary Facilitators –Insure that good vocabulary practices are followed –Actual maintenance of domain specification database –Submit new concepts to vocabulary providers All vocabulary/terminology providers can provide mappings to HL7 domains

37. 3/18/199936© 1999, Health Level Seven, Inc. Domain specification table maintenance Available on HL7 web site –All members can read tables Edit Permissions table –who can edit which domains –vocabulary co-chairs maintain permissions table Assigned persons make edits (proposed status) Entries reviewed by Vocab Review Committee Reports presented to RIM harmonization process Approved changes reflected by status chanages HL7 standard versions synched with edit versions

38. 3/18/199937© 1999, Health Level Seven, Inc. Good Vocabulary Practices Need to define –Jim Cimino –Peter Elkin (ASTM Standard)