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Explore HL7's needs, desiderata, and research on controlled medical terminologies in relation to the National Drug Code (NDC). Discover the importance of unique identifiers, concept orientation, concept permanence, formal definitions, and more.
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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
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
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
Drug Model Hierarchy Packages Medications Drug Class International Package Identifiers Chemicals is-a Not-Fully-Specified Drug is-a Ingredient Class is-a Country-Specific Packaged Product Clinical Drug is-a is-a is-a Ingredient Composite Clinical Drug Trademark Drug is-a is-a Manufactured Components Composite Trademark Drug
Drug Model Hierarchy Packages Medications Drug Class International Package Identifiers Chemicals is-a Not-Fully-Specified Drug is-a Ingredient Class is-a Country-Specific Packaged Product Clinical Drug is-a is-a is-a Ingredient Composite Clinical Drug Trademark Drug is-a is-a Manufactured Components Composite Trademark Drug
Clinical Drugs • Dosage form • Active ingredients • Chemical • Form Strength • Strength amount • Strength units • Volume • Volume units
Content • Needs to be complete • Needs to be up-to-date
Concept Orientation • Unique identifiers associated with meaning • Name can change; meaning cannot • Nonredundant • Unambiguous • Codes can’t be reused
Concept Permanence • Meaning doesn’t change • Never deleted
Nonsemantic Identifiers • Don’t use names • Don’t use mnemonics • Don’t use hierarchical codes
Polyhierarchy • Multiple classes for terms • Multiple views
Nonsteroidal Anti-inflammatory Medication Glaxo Wellcome Products Opiate Analgesic Tablet Aspirin Preparations Codeine Preparations Aspirin 325/Codeine 30mg Tablet Polyhierarchy Empirin #3
Formal Definitions • Avoid misunderstanding of meaning • Allow detection of ambiguity and redundancy • Support multiple classification
Formal Definitions (Empirin #3: (Ingredients: ( (Ingredient Aspirin) (Strength “325”) (Units milligrams) ) ( (Ingredient Codeine) (Strength “30”) (Units milligrams) ) (Form: Tablet) (Manufacturer: Glaxo Wellcome) )
Reject “Not Elsewhere Classified” • Ambiguous (e.g., “Other Antibiotics”) • Semantic drift thwarts concept permanence
Multiple Granularities • Different users need different abstractions
Nonsteroidal Anti-inflammatory Medication Aspirin Preparations Aspirin 325/Codeine 30mg Tablet Multiple Granularities Empirin #3
Graceful Evolution • Avoid: • Redundancy • Major name changes • Code reuse • Changed codes • Support: • Simple addition • Refinement • Minor name changes • Precoordination • Disambiguation • Obsolescence • Discovered redundancy
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
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