Scope

International release criteria include affirmative answers to the following:

• Does it need to be understandable in electronic health applications in more than one national healthcare system?
• Can it be used in electronic health applications beyond a patient's national healthcare system, i.e. if a patient were to travel or relocate to a different country?
• Is it useful in more than one national healthcare system?

The guiding principle underlying the creation of a clinical reference terminology is the facilitation of semantic interoperability.  To this end, content in SNOMED CT must represent unambiguous, clinically relevant information which can be exchanged and understood internationally. A reproducible and consistent approach to incorporating terminology into electronic health applications is, therefore, mandatory.

The International Release includes content necessary for international conformance and interoperability (the International Release was formerly and is colloquially known as the core). The range of concepts, attributes, qualifiers, and other components of SNOMED CT is comprehensive compared to classification systems. This supports the terminological needs of those using SNOMED CT within electronic health applications.

Addition of new content to SNOMED CT requires careful consideration. Changes and additions to the International Release of SNOMED CT follow a formal process executed by SNOMED CT authors.  For content to be included in the International Release, the following criteria must be met.

Broad use

It must be applicable within and across healthcare disciplines internationally.

Provision of use case

Changes and additions must follow SNOMED CT Content Request Service (CRS) Guidelines. It is very important to incorporate a clear justification for any change or addition request for the International Edition of SNOMED CT.

Principle of URU

• Understandable: The terminology must be able to communicate to recipients the intended meaning of the healthcare provider in terms that are unambiguous and comprehensible without reference to inaccessible, hidden, or private meanings.  
• Reproducible: Concepts should be names that are human-understandable representations of the codes. It is not enough for an individual to say they think they understand a meaning. It must be shown that multiple people interpret and use the meaning in the same way.  Can it be used in electronic health applications beyond a patient's national healthcare system, i.e. if a patient were to travel or relocate to a different country?
• Useful: The meaning must have demonstrable use or applicability to health or healthcare. 

Usefulness

Content submitted for inclusion in the International Release shall be required to pass a test for "usefulness." The usefulness test can be passed in more than one way. At least one of the following must be satisfied:

1. Content that is used by more than one major user (a National Release Center such as NHS, a vendor/supplier of clinical information systems with international scope, or a large intra-national system user such as VA or Kaiser) will be considered to have passed the "usefulness" criterion.
2. Data demonstrating significant frequency of use, or frequency of need, by a single user (single national center, or single vendor, or single health care system) can also be used as evidence in support of usefulness.

Additional means of passing the usefulness test may be added in the future. Submissions that pass the usefulness criterion must also pass understandability and reproducibility tests, and conform to style rules.

Naming of classes of things rather than instances

SNOMED CT concepts should name classes of things. Concepts that refer to a particular instance are unacceptable.

For example, Doctor Jones pre-operative order set should not be included because it is an individual instance, not a class.

References

Content must be submitted with:

• Definitions and literature references. All reference material must be publicly available. Wiki references are unacceptable.
• Evidence of international applicability. Without international applicability, a concept should, instead, be added to the submitter's extension.

(See also Appendix: Principles for Accepting Content in the International Release)