1. Building a National Medication Reference Terminology:
VA Experience with NDF-RT
Presented to HL7 Government SIG By Steven Brown & Michael Lincoln, Department of Veterans Affairs
In collaboration with NLM, FDA, NCI and Apelon

2. Why a Common Drug Reference Terminology?
Improve use of drug information by single systems
Improve sharing of drug information by adding semantic understanding to the syntax defined by HL7 messaging between systems

3. VA National Drug File (NDF)
Centrally maintained file of drug products
Distributed to 128 VA Medical Centers
Incorporated into VistA Pharmacy Applications
~ 80,000 Entries
Maintained and used via “M Globals”
VA Product File
VA Active Ingredient File
More than a decade of experience…

4. NDF Uses Within VA National standard listing
Local formularies mapped to NDF standard
Interaction and Order Checking
Consolidated Mail Outpatient Pharmacy
> 7 sites, 57 million prescriptions/year

5. NDF Product File Product Names Form, Strength, Product Identifier
AMOXICILLIN 250MG/CLAVULANATE K 125MG TAB
Form, Strength, Product Identifier
Linked to: VA Drug Class :
AM052 “penicillins, amino derivatives”
Linked to: Active Ingredients

6. NDF - Issues Maintenance Mapping local formularies to NDF
4000 NDC level edits per month
Done largely by hand
Mapping local formularies to NDF
Manual process
Required for CMOP
Decision Support – class based
CN101 “Opioid Analgesics” vs. CN103 “Non-opioid analgesics”

7. NDF Reference Terminology (RT)
Enterprise Architecture project
Goal – to evaluate the use of modern terminology techniques to increase functionality, improve quality and decrease costs

8. Rossi Mori First Generation Terminology
Traditional Paper-Based Terminological Systems with lists of phrases and codes.
E.g. ICD9, CPT

9. Rossi Mori Second Generation Terminology
Compositional terminological systems built according to a categorical structure and a cross-thesaurus with predefined values for each category.
E.g. LOINC

10. Rossi Mori Third Generation Terminology
Reference Terminology –
A terminology where each term has a formal definition designed for data aggregation and retrieval.
Formal terminological systems represent concepts with symbols and rules that create a computable structured and coded system
e.g. SNOMED RT, NDF RT

11. Advantages of Formal Terminology
Computer-based tools
Reduced Maintenance Costs
90% reduction in MED Maintenance effort
Reduced Mapping Effort
60% automated matches to formalized version of LOINC
Comparable Data
Supports Aggregation

12. Reference Terminology Creation
Create a model of use case-based definitional attributes
Create a reference hierarchy for each definitional attribute
Define concepts using terms from reference hierarchies

13. Simplified NDF RT Model
Database Links
DKB Ids, CUIs, Mesh
Structural ID
Chemical Structure
Mechanism of Action
Active Ingredients
Strengths
Dose Forms
Route of Adm.
(HL-7)
Clinical Drug
Therapeutic Use
Pharmacokinetics
National Drug
Codes (NDCs)
Identity Key
Gray = Chemical
Green = Clinical
Pink = Commercial
Blue = Functional
Yellow = External

14. Sample MoA Hierarchy Receptor Interactions Channel Agents Transporter
Enzyme
Interactions
ABC
Transporters
Organic Ion
Transporters
LST-1
Sialin
Transporter

15. Sample Definition AMOXICILLIN 250MG/CLAVULANATE K 125MG TAB
Has_form: tablet
Has_active_ingredient: Amoxicillin
Has_strength 250 mg
Has_MoA: cell wall synthesis disruption
Has_active_ingredient: Clavulanate
Has_strength 125mg

16. NDF RT Progress to Date NDF in terminology development tool
Model Created
Reference Taxonomies
Done: Route, Form, Strength, Structure
Under development : MoA, Physiologic Effect, Therapeutic Intent and Pharmacokinetics
Concept Definition
Algorithmic initialization
Human review
Input from NLM, HL7, FDA, NCI, Apelon

17. NDF RT – Next Steps Sample Applications demonstrating value
Expand Project beyond VA
NLM, FDA, NCI, Regenstrief, ???
Freely available to others for reuse

18. NDF RT Model Chemical Structure Class Database Links
DKB Ids, CUIs
Structural ID
Mechanism of Action
Active Ingredients
Strengths
Dose Forms
Route of Adm.
(HL-7)
Clinical Drug
Therapeutic Use
Finished Dosage Form
Pharmacokinetics
Appearance
Product
Brand Names
Identity Key
Gray = Chemical
Green = Clinical
Purple = Commercial
Blue = Functional
Yellow = External
Packaged Product
National Drug
Codes (NDCs)
Kit