SNOMED CTA Technologist’s Perspective

Gaur SunderPrincipal Technical Officer & Incharge, National

Release CenterVC&BA, C-DAC, Pune

SNOMED CT Origin• A controlled coded clinical terminology for use in Electronic Health Records

– Developed in the USA and the UK by• College of American Pathologists in USA• National Health Service in the UK

• Design based on– Identified user requirements– Practical experience– Scientific principles established in peer reviewed publications

• First released in 2002• All rights and administration transferred for the public good to IHTSDO in

2007• Earlier Systematized Nomenclature for Medicine (SNOMED) – Clinical Terms

(CT), now simply SNOMET Clinical Terms

IHTSDO• IHTSDO: International Health Terminology Standards

Development Organization• Maintains and delivers SNOMED CT

– Licensed to registered Affiliates– IHTSDO does not charge for use in Member countries– Low-cost licenses for institutions in other countries

• Free in lowest income countries• Fee waivers for approved research and “Public Good” uses

• An International not-for-profit standard development organization– Owned by Nations as Members– Governed by General Assembly of its Members

Worldwide Presence• Currently 27 countries are Members of IHTSDO• The clinical terminology is used in more than 50

countries• India became a member in April 2014• Represented by e-Governance Division, Ministry

of Health & Family Welfare, Government of India• Interim National Release Center (NRC) created at

C-DAC, Pune in September 2014

Design Benefits of SNOMED CT• Comprehensive clinical scope

– Reduces need to support multiple code systems– Common framework for consistent retrieval and processing

• Logical definitions– Allow clinically relevant meaning-based retrieval

• Optional post-coordination– Combining codes to add detail and specificity– Increases scope without ‘combinatorial explosion’ of codes

• Updates and versioning– Regular updates to International Release (six-monthly)– Support for incremental updates– Full historical view of all previous versions of SNOMED CT

SNOMED CT – Comprehensive Scope• It is the richest vocabulary available

to describe clinical findings, diseases, procedures etc.

• Contains more than 365,000 concepts, almost 1 million descriptions and nearly one and a half million relationships.

• SNOMED CT aims at transmitting all concepts that have been expressed throughout history in the healthcare domain, unambiguously

• SNOMED CT concepts are divided into 19 hierarchies

SNOMED CT Design• Every coded concept is linked to related concepts– Multi-axial subtype hierarchy (‘is a’ relationships)– Logical definitions (attribute relationships)

SNOMED CT Basic Components• Concepts

– A “concept” is a clinical idea identified by a unique numeric identifier (ConceptID) that never changes

– Concepts are represented by a unique human-readable Fully Specified Name (FSN)

• Descriptions– Concept descriptions are human readable terms or names assigned to a SNOMED CT

concept– Descriptions are of two types

• Fully Specified Name (FSN)• Synonym

– Descriptions can be Preferred or Acceptable according to the language dialect used

• Relationships– Relationships link concepts in SNOMED CT

SNOMED CT Expressions• Precoordinated Expression– Representation of a clinical meaning using a single

concept identifier is referred to as a precoordinated expression

• Postcoordinated Expression– Representation of a clinical meaning using a

combination of two or more concept identifiers is referred to as postcoordination

SNOMED CT Additional Components• Subsets & Reference Sets

– A SNOMED CT subset is a set of Concepts, Descriptions, or Relationships from the international edition that is appropriate to deployment to support particular requirements of implementation

• Extensions– The International Edition contains the core content of SNOMED CT. – Extensions can be added to the International Edition to meet

specific national or local needs• Cross Maps

– Mapping of concepts to other international standards and classifications such as ICD or LOINC

Technical Views• A SNOMED CT Affiliate License is required to obtain the release files• SNOMED CT International Release Files are released biannually (in

Jan and July)• Three release file types exists:

– Snapshot: containing the current version of every component– Full: containing the complete history of every component– Delta: containing only the additions and changes since the previous release

• The snapshot type is recommended to use in applications• All release files are UTF-8 encoded tab-delimited text files• Data in these files need to be imported in relevant tables in database

Integration Approaches• SNOMED CT can be integrated as:

A code system To store clinical information

An interface terminology

To capture and display clinical information

An indexing system To retrieve clinical information

A common terminology To communicate in a meaningful wayTo integrate heterogeneous data

A dictionary To query, analyze and reportTo link health records to knowledge resources

Usage in Software - Search

Usage in Software – Data Entry

Use in Practice• Clinical ideas are complex and interrelated

– A form of representation that captures this inherent complexity is essential• SNOMED CT

– Provides comprehensive coverage of a broad clinical scope– Is designed based on practical experience & scientific principles– Adds value with a concept model that locates clinical ideas relative to one another

in a way that supports computable semantics enabling meaning-based retrieval– Clinicians need to remember the codes as only the descriptions are relevant

• Well-engineered EHR systems using SNOMED CT– Provide user interfaces that simplify capture of clinical ideas– Share information taking advantage of the global terminology– Harness the logical design of the terminology to deliver effective meaning-based

retrieval

EHR Benefits of SNOMED CT• Enhancing the care of individual patients:

– Display of appropriate information– Guideline and decision support integration– Communicating and sharing relevant information

• Enhancing the care of populations of patients: – Epidemiology monitoring and reporting– Research into the causes and management of diseases

• Supporting cost-effective delivery of care: – Guidelines to minimize the risk of costly errors– Reducing duplication of investigation and interventions– Auditing the delivery of clinical services– Planning service delivery based on emerging health trends

India Updates• 74 Affiliate Licensees issued in first year• 06 Workshops / trainings Conducted• More trainings focused on clinical use and

implementations planned• Check official website of India NRC at

https://www.snomedctnrc.in

Thank You

nrc-help@cdac.in info@snomedctnrc.in