This section considers scope as it relates to the incorporation of proprietary names (e.g. brand names of drugs, devices, clinical forms or tools) into SNOMED CT.
Proprietary names are the names that have been assigned to products, usually drugs and devices, by their corporate producers. They do not require a license from the producer. It is both necessary and useful to include proprietary names in a health terminology. SNOMED International does not need to obtain the permission of the trademark owner simply to include a reference to the brand name drug in SNOMED CT. However, they should not be included in the International Release but instead in National Extensions. This is because proprietary names may refer to different products depending on the country and the meaning of these names are dependent on the country or jurisdiction in which the product is approved.
Modeling
A brand or trade name may stand for a category of product and not the particular brand itself. These proprietary names may be included in the International Release as descriptions (non-FSN descriptions). They should not be included in FSNs.
For example,
Disclaimer
Please note that SNOMED International's general policy is to only include generic device concepts within SNOMED CT to maintain its focus on clinical meaning and to avoid endorsement of specific commercial products. Exceptions are approved on a case-by-case basis with documented use cases for those branded devices required to model and define specific clinical findings and procedures.
An exception to the inclusion of brand names of devices has been made to include a select number of devices used in glaucoma treatment. The Eye Care Clinical Reference Group agreed on the list of these devices, acknowledging their consistent international use and representation. The exception is necessary due to the challenge of describing these devices clearly and unambiguously in the SNOMED FSN. Since the selection of these devices is based on their brand names, it is essential to include them in SNOMED CT.
The owner of a form or tool may be an individual or organization that created it; the healthcare organization that employed the individual; or it may be a commercial organization to which the rights were assigned.
Incorporating the name of a clinical form or tool (e.g. the XYZ Test (staging scale)), or the name of the score generated by a form or tool (e.g. the XYZ Test Score (observable entity)) into SNOMED CT does not require a license from the owner. Reference to the owner of a clinical form or tool loosely refers to the person or organization that owns the intellectual property rights of the form or tool. This may be the individual or group that originally created the form or tool, the organization that employed the creators, or a commercial organization to whom the creators assigned their intellectual property rights. It is possible that the owner holds a trademark (which may be registered or unregistered) representing the name or score, but simply incorporating that word into SNOMED CT does not infringe on the trademark.
A concept may be introduced into SNOMED CT that represents the text of questions, answers, or scores. For example, a form may include a question about a person's ability to dress and a range of possible answers. SNOMED CT may incorporate neither the text of the question nor any of the possible answers, but instead may incorporate a concept such as ability to dress. Similarly, if the form contains 20 questions, SNOMED CT may want introduce 20 concepts, for XYZTest_Result1 , XYZTest_Result2, etc. to XYZTest_Result20.
The incorporation of a single concept into SNOMED CT , based on a question, answer, or score on a clinical form is highly unlikely to infringe on the copyright. However, if SNOMED CT systematically introduces a concept for every single question on a clinical form, it is likely to infringe on the copyright.
These concepts (e.g. ability to dress) may already exist in SNOMED CT, or they may be added in other contexts (This does not apply to concepts that represent specific questions within a form). This is unlikely to result in a copyright infringement.
Questions
A clinical form or tool, including the wording of the individual questions within the form or tool, is generally a literary work and qualifies for copyright protection (except in the case of the simplest of forms). The copying of all or any substantial part of a literary work, without a license from the owner, infringes on the copyright.
Answers
Certain questions may have a range of pre-determined answers. This could be as simple as Yes/No or a number within a specific range, but may also be more substantial (e.g. needs help cutting, spreading butter, etc. , or requires modified diet). Incorporating very simple answers into SNOMED CT does not require permission. However, incorporating more substantial textual answers into SNOMED CT generally infringes on the copyright. This usually does not apply to individual answers, but it almost always applies when entire sets of answers are incorporated.
Scores
The principles that apply to individual answers also apply to the overall score generated by a clinical form or tool. The incorporation of numbers does not infringe on the copyright. However, when each possible score has an associated textual description and all possible scores and descriptions are incorporated into SNOMED CT, a license is required.
For example,
443807003 | EuroQoL five dimension questionnaire (assessment scale)| is a SNOMED CT concept. However, these scores are subject to copyright protection, therefore cannot be added to SNOMED CT:
EuroQol Five Dimension (youth) doing usual activities score
EuroQol Five Dimension (youth) feeling worried, sad or unhappy score
The use of the name of a clinical form or tool or of a brand name drug will usually not infringe on the copyright. However, caution should be exercised by implementers who wish to use trademarks in a commercial context, i.e. a system that enables drugs to be purchased electronically. SNOMED International does not advise implementers on this matter, but recommends that implementers, who are in any doubt, contact the trademark owner.
In general, implementers should make no greater use of a trademark than is necessary. For example, displaying a graphical mark (e.g., a logo) on a screen or in printed material should be avoided.
Implementers should manage questions, answers, and scores in the same way as SNOMED International. When the incorporation of content from a clinical form or tool infringes on the copyright, the system the reproduces (by display or print) the content also usually infringes. This means that the license to incorporate content by SNOMED International should also cover the system implementer.
As noted above, terms in a clinical form may already exist within SNOMED CT, even though they have not been copied from the form. This is not copyright infringement by SNOMED International. If, however, a system implementer chooses to arrange a collection of these pre-existing terms in a way that reproduces all or a substantial part of a clinical form (e.g., by populating a drop-down box with all of the possible answers to a specific question on the form), that may infringe on the copyright.
A system may reproduce the structure and layout of a clinical form on a screen display or printed output (e.g., to make the system more accessible to users who are familiar with a paper-based form). This may infringe on the copyright, unless the structure or layout is very minimal (e.g., a bulleted list). An implementer who wishes to emulate the look and feel of a clinical form should seek a license from the owner.
System implementers may use the algorithm or logic inherent in a clinical form or tool (e.g. the method by which an overall score is calculated). For example, a clinical form may instruct the user to perform a mathematical operation on the individual answers to produce the overall score, and the same operation may be carried out by the system. The use of the algorithm or logic is an infringement. SNOMED International avoids such use and encourages system implementers to contact the owner to discuss possible infringement.
There are processes for making decisions about adding or changing content in SNOMED CT.
All change requests, whether for new content or for change to existing content, go through a request submission approval process. It involves review by authors to determine that there is:
International applicability
Compliance with Understandable, Reproducible, Useful (URU) principles
No duplication with existing content
No link to existing larger projects, as detailed in a Content Tracker document
No conflict with existing collaboration agreements (e.g. Logical Observation Identifiers Names and Codes (LOINC) agreement)
Requests that are rejected may be appealed by the submitter.
Requests may be deferred for a number of reasons including questions about:
How to model the concept; which attributes may be used
Concept meaning
Literature reference missing or inadequate
Use case unclear
Resolution of deferrals may result in a decision delay requiring:
A larger project or work item or
Referral, internally, to other groups for decision. This depends on the complexity of the request and understanding of the wider impact.
Results of adjudication are received by email from the Content Request System (CRS). Simpler issues can be resolved expeditiously (e.g. by a ruling from the Chief Terminologist).
Size of required change (attached to a Content Tracker)
Legacy concepts, i.e. concepts not in the current draft/work-in-progress version of SNOMED CT, may not follow current guidelines. Requests based on legacy concepts are unacceptable.
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.
Content must be submitted with:
Submissions for a change to the international release of SNOMED CT must be supported by at least one reference that is of international relevance. Please remember that requests for change need to be of international application and not confined to one member country. We may require more than one reference to assess the validity and international applicability for some areas of content.
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.
For details on SNOMED International Content Request Service (CRS) Customer Guidance, see the SNOMED International or the .
It must be applicable within and across healthcare disciplines internationally.
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.
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. 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:
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.
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.
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.
Negation in SNOMED CT is generally out of scope for the terminology. However, SNOMED CT currently has content which incorporates negation in several hierarchies. This is due to the amalgamation of legacy content from Read Codes and SNOMED RT in 2002 when the two terminologies formed SNOMED CT. The description logic approach to negation comes with a high machine processing cost, and so the decision was to deal with all negation via the Situation with explicit context hierarchy. The consequence of this approach is that the representation of negation within SNOMED CT that arises from restrictions imposed by the existing description logics results in the hierarchy being inverted, e.g., Coronary heart disease not present is not properly a subtype of Heart disease not present.
For these reasons, software vendors are encouraged to store negation in the electronic health record rather than looking for a concept which encapsulates its meaning. Storing negated findings in a separate field in the EHR, for example, would simplify querying data.
Including patterns and trends in SNOMED CT, such as ‘weight increasing’ or ‘weight decreasing,’ is not advisable for several reasons:
Purpose of SNOMED CT : SNOMED CT is designed to provide a comprehensive set of clinical terms for supporting clinical care and consistent data exchange. Patterns and trends pertain more to data interpretation and analysis, which is outside the scope of clinical terminology. However, summary statements relating to patterns can be clinically relevant and should be represented in SNOMED, e.g. 422868009 |Unexplained weight loss (finding)|
Appropriate Tools : Patterns and trends are better managed by the information model or statistical and analytical tools, not terminology. Including them in SNOMED CT could confuse the distinction between data capture and data analytics. Trend data can be captured using additional metadata such as timestamps. Clinical decision support systems can also interpret and act on trends.