This section provides an overview of:

Why is this important?

The objective of and all users of SNOMED CT is to facilitate the accurate recording and sharing of clinical and related health information and the semantic interoperability of health records.

What is this?

How SNOMED CT Supports Reuse of Clinical Information

is a clinical terminology with global scope covering a wide range of clinical specialties, disciplines and requirements. As a result of its broad scope, one of the benefits of  is a reduction of specialty boundary effects that arise from use of different terminologies or coding systems by different clinicians or departments. This allows wider sharing and reuse of structured clinical information. Another benefit of  is that the same data can be processed and presented in ways that serve different purposes. For example, clinical records represented using can be processed and presented in different ways to support direct patient care, clinical audit, research, epidemiology, management and service planning. Additionally, the global scope of SNOMED CT reduces geographical boundary effects arising from the use of different terminologies or coding systems in different organizations and countries.

With , clinical information is recorded using identifiers that refer to concepts that are formally defined as part of the terminology.  supports recording of clinical information at appropriate levels of detail using relevant clinical concepts. The structures of  allow information to be entered using synonyms that suit local preferences while recording the information in a consistent and comparable form. Additionally, the hierarchical nature of  permits information to be recorded with different levels of detail to suit particular uses (e.g. |pneumonia|, |bacterial pneumonia| or |pneumococcal pneumonia|).  allows additional detail to be added by combining concepts where the available concepts are not sufficiently precise (e.g. |pneumococcal pneumonia| with a |finding site| of |right upper lobe of lung|).  allows a range of different options for immediate retrieval and subsequent reuse to address immediate and longer term clinical requirements and the requirements of other users. The nature of  hierarchies allow information to be selectively retrieved and reused to meet different requirements at various levels of generalization (e.g. retrieval of subtypes of |lung disorder| or |bacterial infection| would both include |bacterial pneumonia|).

The also allows additional details to be considered when retrieving data. For example, the concept |pneumococcal pneumonia| is a of |bacterial pneumonia| which has a  that specifies that the |causative agent| is |streptococcus pneumoniae| and this allows the organism causing this disease to be analyzed.

Extent of Practical Use

Many systems use  to represent some types of clinical information. The extent of use is varied in terms of:

Approaches to Implementation

 has been implemented in a variety of ways which differ in the extent to which they harness particular features of the terminology. In some cases, these differences merely reflect the specific requirements of a particular use. Other factors include the design of existing systems prior to the introduction of  , sophistication of available technology and support for a range of other health informatics standards.

Key determinants for effective benefits realization include:

Lessons Learnt

The features of  support reusability of clinical information. However, reusability also requires a consistent structured representation of clinical information that complements the meaning supported by . Without this, overlaps and conflicts between structural and terminological representations of clinical content can result in ambiguous and potentially conflicting interpretations.

The way in which the use of terminology and structure together contribute to the representation of meaningful information is sometimes referred to as the "model of meaning". To enable widespread clinical information reuse, queries need to be consistently formulated in ways that take account of the way the information is structured and coded. A common model of meaning facilitates widespread reuse of clinical information, ability to reuse queries and a consistent approach to linkage between clinical information and knowledge resources.

Human factors may result in inconsistent recording of similar clinical information. This issue can be minimized by effectively constraining data entry.


An important limitation is the diversity of views related to the structure of clinical information and the overlap between information models and terminology. There are also differing views on application design, different requirements for collection of clinical information and different views on record structures and data entry methods appropriate to different use cases.

SNOMED International is working with other standards bodies including the International Organization for Standardisation (  ) and  (HL7), as well as various collaborative efforts exploring the relationship between terminology and structured clinical information. The objective is to ensure that the role of  as a key component of clinical information and systems is understood as part of overall efforts towards harmonization and interoperability.