This section provides an overview of:

Why is this important?

An awareness of  features,  , characteristics and products provides an initial foundation on which to build greater understanding. It also informs discussions leading to decisions about adoption, implementation and use of this terminology.

What is this?

SNOMED CT Features


When implemented in software applications, can be used to represent clinically relevant information consistently, reliably and comprehensively as an integral part of producing electronic health information.

Implementation requires an understanding of the way that  content is represented by  and supported by  (Refsets).

Exploring SNOMED CT

While reading the guide, you may find it useful to explore the content of . You can do this using one of a range of online listed on our web site at Note that the listed  are not endorsed by  and they should only be used to a get feel for the content and structure of the terminology. It is useful to experiment with several different  as they vary in the way they present particular features of the terminology.


SNOMED CT Design and Development

SNOMED CT Components

SNOMED CT is a core clinical healthcare terminology that contains with unique meanings and formal logic based definitions organized into .  content is represented using three types of :

These  are supplemented by , which provide additional flexible features and enable configuration of the terminology to address different requirements.


represent clinical thoughts, ranging from |abscess| to |zygote|. Every  has a unique numeric . Within each are organized from the general to the more detailed. This allows detailed clinical data to be recorded and later accessed or aggregated at a more general level.


link appropriate human readable terms to . A  can have several associated , each representing a  that describes the same clinical concept. Each  of  includes an additional set of , which link  in another  to the same . Every  has a unique numeric


 link concepts to other  whose meaning is related in some way. These  provide formal definitions and other properties of the . One type of is the  which relates a to more general . These  define the of

Other types of  represent aspects of the meaning of a

Every  has a unique numeric

Reference sets

(Refsets) are a flexible standard approach used by  to support a variety of requirements for customization and enhancement of . These include the representation of , language preferences for use of particular  and  from or to other code systems. Every  has a unique numeric

SNOMED CT Hierarchies

 are organized in hierarchies. Within a range from the more general to the more detailed. Related  in the are linked using the |is a| relationship.

SNOMED CT Characteristics - Comprehensive, Scalable and Flexible

has a broad coverage of health related topics. It can be used to describe a patient's medical history, the details of an orthopedic procedure, the spread of epidemics, and much more. At the same time, the terminology has an unmatched depth, which enables clinicians to record data at the appropriate level of granularity.

Specific applications tend to focus on a restricted set of , such as  related to ophthalmology. These  can be used to present relevant parts of the terminology, depending on the clinical context and local requirements. This means for example, that a drop down list to select diagnoses in an  in a mental health facility can be tailored to that setting. Similarly,  can be defined for problem lists for physician specialties or to provide appropriate medication lists for nurses in community care.

When individual jurisdictions have needs beyond those that can be reflected in a global terminology, perhaps due to requirements in local legislation, they can develop local or national . Thus, even though  is global in scope, it can be adapted to each country's or areas requirements.  maps work to provide explicit links to health related classifications and coding schemes in use around the world, e.g.  such as , and . Maps to or from several national code systems are also available from, or under development, by . Maps to or from clinical domain specific code systems are also maintained by specialty groups with which  has collaborative agreement. Maps facilitate reuse of  based clinical data for other purposes, such as reimbursement or statistical reporting.

Supporting Different Languages

 is a multinational, multilingual terminology. It has a built-in framework to manage different  and . The  includes a set of language independent  and . Today,  is available in US English, UK English, Spanish, Danish and Swedish. Partial  into Canadian French, Lithuanian, and several other  are currently taking place, and further are being planned by The basic objective of any  is to provide accurate representations of  in a way that is understandable, usable, and safe. must be  based. Translators need to analyse based on the  and take account of its position within the , its , and its  to other . This enables a meaningful  of a  based on phrases that are well used and clearly understood in all countries.  maintains guidelines and other materials to support countries undertaking translations.

SNOMED CT Products and Services

 and organizations covered by the SNOMED CT  have access to a range of products and services, including: