1. The Future of NDC: The HL7 Perspective James J. Cimino, M.D. Co-chair, HL7 Vocabulary Technical Committee Departments of Medicine and Medical Informatics Columbia University College of Physicians and Surgeons

2. Outline HL7’s Needs Desiderata –Summary of 10+ years of research on controlled medical terminologies –Presented at IMIA Working Group 6, Jacksonville, FL, 1997 NDC and the Desiderata HL7’s Perspective of NDC

3. HL7 Needs Drug Codes to... …transfer medication orders from an order entry system to a pharmacy …aggregate data from multiple sources …serves as grist for decision support engines …just about anything else you can imagine

4. Drug Model Hierarchy Drug Class Not-Fully-Specified Drug Clinical Drug Trademark Drug Manufactured Components Ingredient Class International Package Identifiers Country-Specific Packaged Product Ingredient is-a Chemicals Medications Packages Composite Clinical Drug is-a Composite Trademark Drug is-a

5. Drug Model Hierarchy Drug Class Not-Fully-Specified Drug Trademark Drug Manufactured Components Ingredient Class International Package Identifiers Country-Specific Packaged Product Ingredient is-a Chemicals Medications Packages Composite Clinical Drug is-a Composite Trademark Drug is-a Clinical Drug

6. Clinical Drugs Dosage form Active ingredients –Chemical –Form Strength Strength amount Strength units Volume Volume units

7. Content Needs to be complete Needs to be up-to-date

8. Concept Orientation Unique identifiers associated with meaning Name can change; meaning cannot Nonredundant Unambiguous Codes can’t be reused

9. Concept Permanence Meaning doesn’t change Never deleted

10. Nonsemantic Identifiers Don’t use names Don’t use mnemonics Don’t use hierarchical codes

11. Polyhierarchy Multiple classes for terms Multiple views

12. Polyhierarchy Empirin #3 Aspirin 325/ Codeine 30mg Tablet Aspirin Preparations Codeine Preparations Opiate Analgesic Nonsteroidal Anti-inflammatory Medication Glaxo Wellcome Products Tablet

13. Formal Definitions Avoid misunderstanding of meaning Allow detection of ambiguity and redundancy Support multiple classification

14. Formal Definitions (Empirin #3: (Ingredients: ( (Ingredient Aspirin) (Strength “325”) (Units milligrams) ) ( (Ingredient Codeine) (Strength “30”) (Units milligrams) ) (Form: Tablet) (Manufacturer: Glaxo Wellcome) )

15. NEC

16. Reject “Not Elsewhere Classified” Ambiguous (e.g., “Other Antibiotics”) Semantic drift thwarts concept permanence

17. Multiple Granularities Different users need different abstractions

18. Multiple Granularities Empirin #3 Aspirin 325/ Codeine 30mg Tablet Nonsteroidal Anti-inflammatory Medication Aspirin Preparations

19. Graceful Evolution Support: –Simple addition –Refinement –Minor name changes –Precoordination –Disambiguation –Obsolescence –Discovered redundancy Avoid: –Redundancy –Major name changes –Code reuse –Changed codes

20. NDC and the Desiderata Content - timeliness and comprehensiveness Concept orientation - done Concept permanance - needs work Nonsemantic identifiers - worst of both worlds Polyhierarchy - may be beyond purview of FDA Formal definitions - easily accomplished Reject “NEC” - done (watch out for hierarchies) Multiple granularities - as per polyhierarchy Graceful evolution - editorial policy needed

21. HL7’s Perspective Need unique identifiers for: –Clinical (orderable) products –Dispensable products –Classes –Drug forms –Delivery routes Need all these in a timely, high-quality form Not all need come from FDA