The Language of Healthcare: Exploring SNOMEDCT
Welcome to our newest blog series, where we delve into the essential healthcare terminologies that shape the future of healthcare and data management across industries. Stay informed— Sign Up For TermHub to receive the latest updates and insights delivered straight to your inbox. Whether you’re in healthcare, IT, research, or any field that touches health information, understanding these standards can directly impact your work. These terminologies are not just technical jargon—they’re the foundation of how we improve patient care, streamline data exchange, and enable groundbreaking research.
In the coming weeks, we’ll unravel key terminologies like SNOMEDCT, LOINC, and ICD10, offering clear explanations and real-world examples to help you see their relevance in your field. Whether you’re looking to improve data accuracy, support clinical decisions, or simply stay informed, this series is for you.
We kick off with SNOMEDCT, a global standard that supports the seamless exchange and analysis of health information. While this blog provides images and static links to SNOMEDCT, be sure to explore it hands-on in TermHub’s public SNOMEDCT project. Curious about how this impacts your work? Follow along as we release new posts every week, each demystifying a different terminology and offering insights that you can apply in your day-to-day operations. Like TermHub at LinkedIn to stay ahead and ensure you don’t miss out on valuable insights that could transform how you approach healthcare data.
What is SNOMEDCT?
Developed and maintained by SNOMED International, SNOMED CT (Systematized Nomenclature of Medicine – Clinical Terms) is a comprehensive, standardized healthcare terminology used globally to represent clinical concepts. It provides structured identifiers and detailed definitions that precisely capture the clinical meaning of diagnoses, procedures, symptoms, medications, anatomical structures, and more.
SNOMED CT serves as a unifying standard that facilitates accurate clinical documentation, supports interoperability between electronic health records (EHRs), clinical decision support systems, and healthcare analytics platforms. By standardizing clinical terms across diverse medical specialties and healthcare settings, it enables consistent data sharing, improved patient care, and enhanced outcomes analysis.
As the most widely adopted clinical terminology worldwide, SNOMED CT is essential for hospitals, clinics, research institutions, public health agencies, and healthcare IT vendors. Its extensive coverage and precision make it invaluable for clinical documentation, health data exchange, population health management, regulatory compliance, and advanced healthcare analytics.
What does a SNOMEDCT Concept look like?
Each SNOMED CT concept includes a unique identifier (concept ID), fully specified names, synonyms, hierarchical relationships, definitions, and specialized groupings known as reference sets. These elements precisely capture clinical meanings and support flexible clinical and regional use cases.
Below are two visual representations of commonly used SNOMED CT concepts, along with links to additional examples available in TermHub. These examples highlight the depth and breadth of SNOMED CT, demonstrating its critical role in supporting healthcare practices across diverse clinical specialties.
Symptoms:
Anatomical Structures:
Medications:
Clinical Findings:
Laboratory Tests:
Devices:
What clinical use cases does SNOMEDCT best support?
SNOMED CT is a comprehensive, multilingual clinical terminology that standardizes the representation of healthcare information across diverse settings. It plays a critical role in clinical documentation, decision support, interoperability, and analytics, facilitating clear and precise communication of patient information.
Top Clinical Use Cases:
Clinical Documentation: Supporting precise and detailed clinical documentation to reduce ambiguity.
Clinical Decision Support Systems (CDSS): Providing structured terminology to enhance diagnosis, treatment planning, and alerts for clinical safety.
Data Analytics and Research: Enabling aggregation and analysis of clinical data to improve population health management and clinical research.
Interoperability: Facilitating consistent data exchange and interpretation across health information systems and institutions.
Reporting: Standardizing clinical outcomes, quality metrics, adverse events, and public health surveillance reporting.
Billing and Reimbursement: Supporting detailed clinical descriptions for accurate mapping to billing codes, though not its primary role.
SNOMED CT promotes clear clinical communication, interoperability, and comprehensive healthcare analytics across the industry.
How granular are SNOMEDCT concepts in representing clinical information?
SNOMED CT achieves exceptional granularity by providing highly detailed and structured clinical concepts with hierarchical relationships, definitions, and synonyms. It supports precise representation and interoperability of clinical data across diverse healthcare settings.
An illustrative example highlighting Hierarchical Specificity:
No location: Fracture of bone (125605004)
General location: Fracture of lower limb (46866001)
Specific location: Fracture of bone of left femur (1303377000)
Highly specific location: Open fracture of base of neck of left femur (10821891000119104)
Other examples demonstrating SNOMED CT granularity include:
Procedural Precision:
Colonoscopy (73761001)
Colonoscopy using cecal retroflexion technique (48021000087103)
Clinical Context
Diabetes mellitus (73211009)
Gestational diabetes mellitus (11687002)
Clinical Severity:
Pulmonary hypertension (70995007)
Severe pulmonary hypertension (840308008)
Disease Specificity:
Pneumonia (233604007)
Pneumonia caused by Schistosoma japonicum (707507003)
Medication Context:
Administration of medication (18629005)
Medication administration: nasal (406172003)
This granularity facilitates detailed clinical documentation, supports precise clinical decision-making, and enables powerful data analytics and interoperability.
What are the basic components of SNOMEDCT?
In the SNOMEDCT Logical Model, there are three fundamental building blocks, each with associated attributes. Some attributes, like status or moduleId, are common across all three component types, while others are unique to the specific component they describe.
To illustrate this, consider the concept Appendectomy - Concept ID: 80146002. Below, you will find a visual representation of each component, along with some of the key attributes that define them.
Concept: A Concept is the core organizational entity within SNOMEDCT, serving as the anchor point for the other two components: Terms and Relationships. The Concept represents a distinct clinical idea or entity, such as a procedure, condition, or anatomical structure. One of the key attributes unique to the Concept component is definitionStatusId, which defines the concept's status in terms of whether it is fully defined or primitive within the SNOMEDCT framework.
Term: Terms, referred to as Descriptions in SNOMEDCT, provide the human-readable representation of a concept. Each concept can have two or more descriptions associated with it, allowing for variations in how the concept is expressed or understood.
For example, SNOMEDCT supports language localization by using multiple attributes to facilitate the use of any language and to associate descriptions with specific regional dialects. These attributes ensure that descriptions are accurately tailored to meet the linguistic and cultural needs of different regions.
Relationship: Relationships bind two concepts together within the SNOMEDCT graph, connecting them across different hierarchies. Each "source" concept can have one or more relationships that link it to other concepts. The combination of a concept’s attributes, its relationships, and the attributes of each relationship collectively defines the concept's unique clinical meaning.
Relationships have multiple specific attributes, including Defining and Group, which play a crucial role in precisely defining the nature and context of the relationship between concepts.
What is the release schedule of SNOMEDCT?
In addition to the International Edition, there are various other SNOMEDCT extensions and derivative products, each with its own release schedule. These schedules depend on the managing organization and the time required to incorporate updates from the International Edition. For example, the International Edition of SNOMEDCT (published by SNOMED International), is published monthly. Some extensions, such as the US Extension, have regular release schedules, while others are released only when the managing organization deems the content ready for a specific purpose (such as the Veterans Health Administration Extension of SNOMEDCT).
For a comprehensive overview of the available SNOMEDCT extensions and derivative products, including their respective release dates, you can refer to the SNOMED International Service Catalog. The catalog provides detailed information about each product, helping users navigate the complexities of the SNOMEDCT ecosystem and stay informed about the timing of critical updates.
How do identifiers work in SNOMEDCT?
SNOMEDCT identifiers have structure to identify what type of component and where the identifier originated from. The main components of identifiers are:
Item Identifier: This is a numeric value that uniquely identifies a concept, description, or relationship within SNOMEDCT. It is the core component of the SCTID and ensures that each item within SNOMEDCT has a unique identifier.
Namespace Identifier: This optional component, issued by SNOMED International, ensures that identifiers created by different organizations or extensions are globally unique. The namespace identifier is used only when the SCTID is part of an extension, not for the core SNOMEDCT content.
Partition Identifier: The partition identifier helps in distinguishing between different types of components within SNOMEDCT. This identifier specifies the type of component the SCTID refers to:
00 or 10 are concepts
01 or 11 are descriptions
02 or 12 are relationships
Depends on where the identifier was originally created
The choice between each of the two component’s options (e.g., 00 vs. 10) depends on where the identifier was originally created.
Check Digit: The check digit is calculated using the Verhoeff algorithm, which helps in detecting errors in the SCTID. This ensures the integrity and correctness of the identifier, providing an additional layer of validation.
What type of knowledge graph does SNOMEDCT utilize?
SNOMEDCT is structured as a concept-based terminology system that can be represented as a directed acyclic graph (DAG). In this graph, each node represents a clinical concept, while the edges represent relationships between these concepts.
The graph structure of SNOMEDCT facilitates efficient querying and reasoning over the terminology, which supports clinical decision-making, interoperability, and detailed data analysis in healthcare systems.
Key Characteristics of the SNOMEDCT Graph:
Nodes (Concepts): Each node in the graph represents a unique clinical concept. These concepts can range from diseases and procedures to anatomical structures and clinical findings.
Edges (Relationships): The edges between the nodes represent various types of relationships, such as "is a" (hierarchical relationships), "procedure site," or "associated with." For example, the concept "Pneumonia" might have an "is a" relationship with "Lung Disease."
Hierarchy: The "is a" relationships create a hierarchical structure in which more specific concepts are linked to more general ones. This allows for inheritance of properties from parent to child concepts.
Acyclic Nature: The graph is acyclic, meaning there are no loops. This ensures that a concept cannot be a descendant of itself, which maintains a clear hierarchical structure.
Multiple Parents: A concept can have multiple parent concepts, reflecting the complexity and multiple dimensions of medical knowledge. For example, a specific type of lung cancer might be classified under both "Lung Diseases" and "Cancers."
Can SNOMEDCT be customized?
Yes, SNOMEDCT allows for customization through extensions, enabling countries, regions, or institutions to add components that reflect their unique healthcare practices and needs. For example, the United States has developed its own extension of SNOMEDCT to include content that is required by the U.S. but is not considered clinically applicable internationally. This U.S. Extension can then be further customized by organizations within the U.S. For instance, the Veterans Health Administration (VHA) has its own extension of SNOMEDCT to support content that is specifically relevant to the VHA and not necessarily to the broader U.S. healthcare system or internationally.
Content from any extension can be promoted to its parent extension, including the international core, if it gains broader applicability.
Many National Release Centers (NRCs) also offer ways to submit requests for changes to SNOMEDCT, either through a formal content request submission system or via a simple email process. For example, in the United States, you can request changes through the US SNOMEDCT Content Request System (USCRS).
Who Maintains SNOMEDCT?
SNOMEDCT is owned and maintained by SNOMED International, formerly known as the International Health Terminology Standards Development Organisation (IHTSDO). SNOMED International is a not-for-profit organization responsible for the ongoing development, maintenance, and distribution of SNOMEDCT. Established in 2007, SNOMED International’s membership comprises national health authorities and other bodies from around the world. This global collaboration ensures that SNOMEDCT remains a relevant, up-to-date, and comprehensive clinical terminology system that meets the diverse needs of the healthcare sector worldwide.
SNOMED International publishes the core content of SNOMEDCT, which is applicable globally, while member countries maintain and publish their own extensions. Although SNOMED International publishes the core content monthly (a practice updated in 2021), each extension is released according to a schedule defined by the member countries.
Key Resources
Website: https://www.snomed.org/
YouTube: https://www.youtube.com/@snomedct
Conference Information: https://www.snomed.org/events
What is the History of SNOMEDCT?
SNOMEDCT is a comprehensive, multilingual clinical healthcare terminology that has evolved significantly since its inception. The origins of SNOMEDCT can be traced back to 1965, when the College of American Pathologists (CAP) developed the Systematized Nomenclature of Pathology (SNOP). This initial work laid the foundation for a more expansive clinical terminology system. Over the following decades, the CAP expanded SNOP to cover broader clinical areas, leading to the release of SNOMED International and eventually SNOMED Reference Terminology (RT).
In 2002, a significant milestone was reached when SNOMED RT merged with the United Kingdom’s Clinical Terms Version 3 (CTV3), commonly known as the Read Codes. This merger resulted in the creation of SNOMEDCT, a more comprehensive and detailed clinical terminology system designed to support a wide range of healthcare applications. In 2007, the development and maintenance of SNOMEDCT were taken over by the International Health Terminology Standards Development Organisation (IHTSDO), now known as SNOMED International.
What challenges come with using SNOMEDCT?
Implementing and maintaining SNOMEDCT can present several challenges. Addressing these challenges requires careful planning, collaboration among stakeholders, and a commitment to ongoing education and system improvement.To avoid pitfalls, it is often recommended to work with experts experienced in SNOMEDCT and the challenges of integrating it into an existing ecosystem.
Here are some of the typical issues faced:
Complexity and Learning Curve:
Volume and Detail: SNOMEDCT is extensive, with hundreds of thousands of concepts, making it complex to navigate and understand.
Training: Significant training is required for implementation staff to effectively use and implement SNOMEDCT.
Resource Intensity:
Implementation Costs: The costs associated with implementing any terminology, including SNOMEDCT, can be substantial.
Maintenance: Keeping SNOMEDCT up-to-date with the latest clinical knowledge requires ongoing effort and resources.
Data Quality and Accuracy:
Accuracy of Coding: Ensuring that healthcare providers accurately code clinical information using SNOMEDCT is crucial for data quality but can be challenging.
Data Validation: Continuous validation and auditing are required to maintain high-quality data within healthcare systems using SNOMEDCT.
How do I access and what are the licensing restrictions for SNOMEDCT?
Access to SNOMEDCT is typically managed through a member country’s National Release Center (NRC). SNOMED International does not charge for the use of SNOMEDCT in SNOMED International Member countries or territories. However, a fee may apply for the use of SNOMEDCT in non-Member territories, which requires an affiliate license.
For more information about accessing and licensing SNOMEDCT, you can visit SNOMED International: https://www.snomed.org/get-snomed