A semantic tag is part of a concept's Fully Specified Name description. It is placed in parentheses at the end of an FSN when authoring concepts. It indicates the domain to which a concept belongs; for example: body structure, disorder, or specimen.
The purpose of semantic tags is to disambiguate concepts which have the same commonly used word or phrase.
For example,
Hematoma (morphologic abnormality)
Hematoma (disorder)
The following table contains the semantic tags for each domain.
Body structure (body structure)
(body structure)
-(cell)
-(cell structure)
-(morphologic abnormality)
Clinical finding (finding)
(finding)
-(disorder)
A definition is a textual description applied to some SNOMED CT concepts that provides additional information about the intended meaning or usage of the concept. Definitions are not mandated and are considered for addition on a case-by-case basis, and if required, to differentiate a concept from its related concepts.
Adding a definition to a concept provides additional clarity on its context of use. It enhances the definition provided by the modeled relationships whereby a term can be sufficiently defined logically, but the words, which is how many look for and interpret meaning, may imply more or less specificity.
Definitions must:
be written as complete sentences,
begin with a capital letter,
end with a period,
apply a case sensitivity of Entire term case sensitive (CS).
For example,
The definition for the concept 11530004 | Brittle diabetes mellitus (finding)| is:
Frequent, clinically significant fluctuations in blood glucose levels both above and below levels expected to be achieved by available therapies.
The language acceptability default for a single Definition description is Preferred. A definition with varying US and GB English descriptions are each applied with the respective language acceptability.
For example,
A text definition should be considered where a concept references the obscure or unusual. As an example, raised blood pressure is a commonly used phrase, which, in itself, is ambiguous. Raised can mean: 1) higher than a previous measurement, 2) on the high side of normal range, or 3) above reference range. Because of that ambiguity, a full definition created by logical model may be impossible, so a text definition could be used to encourage consistent use of the term.
The following principles for definition creation are summarized below from ISO-704, Terminology work — Principles and methods :
In summary, if a term may be interpreted in multiple ways, but is intended to mean only one way in SNOMED CT, it needs a definition. However, ultimate source of truth for meaning remains with the FSN.
A concept has multiple associated descriptions.
Each description has a description type and a unique numeric description identifier.
Fully specified name (FSN) and synonym (SYN) are description types in SNOMED CT.
A preferred term (PT) is a synonym that has been marked as preferred in a particular dialect.
Every concept may have only one preferred term in a specific dialect. Two preferred terms for the same language may coexist if they belong to two distinct dialects (e.g. variant US and GB of English language).
Disjunctives (for example, and/or) should be in lower case.
An FSN is one type of description, unique among active descriptions in SNOMED CT. It provides the meaning of a concept so that it is unambiguous, stable across multiple contexts, and optimally understandable to those whose first language is not English. Consequently, it is not always clinician-friendly or in common use. In the majority of cases, where the FSN is clinician-friendly and in common use, a description matching the FSN should be added to the concept. This description is not required to be the preferred term (PT). In certain instances, where the FSN does not provide a clinically useful description, a matching description without the semantic tag is unnecessary.
For example,
A preferred term (PT) is the description that is deemed to be the most clinically appropriate way of expressing a concept in a clinical record. It represents a common word or phrase used by clinicians to name a concept in clinical practice or in the literature. It is the synonym that is preferred in a language or dialect.
The use of a description can vary between different languages, dialects and contexts. A description may be preferred in some dialects, acceptable in others, and may not be used in some dialects. A Language Reference Set is used to specify the descriptions that are preferred or acceptable in each language or dialect.
A concept may have two descriptions marked as PT, one for each language.
For example, 32849002 | Esophageal structure (body structure)| has
PT: Esophageal structure (US)
PT: Oesophageal structure (GB)
A PT for one concept may also be a synonym for another concept.
For example,
84162001 | Cold sensation quality (qualifier value)| has a preferred term of cold
82272006 | Common cold (disorder)| also has a synonym of cold
In both concepts, cold represents a common clinical phrase used to capture the meaning of the concept.
The PT is indicated by the acceptabilityId field, for a particular language or dialect.
Environment or geographical location (environment / location)
(environment)
(geographic location)
Event (event)
(event)
Observable entity (observable entity)
(observable entity)
Organism (organism)
(organism)
Pharmaceutical / biologic product (product)
(clinical drug)
(medicinal product)
(medicinal product form)
(physical object)
(product)
Physical force (physical force)
(physical force)
Physical object (physical object)
(physical object)
-(product)
Procedure (procedure)
(procedure)
-(regime/therapy)
Qualifier value (qualifier value)
(qualifier value)
-(administration method)
-(basic dose form)
-(calculation)
-(disposition)
-(dose form)
-(intended site)
-(product name)
-(release characteristic)
-(role)
-(state of matter)
-(transformation)
-(supplier)
-(unit of presentation)
Record artifact (record artifact)
(record artifact)
Situation with explicit context (situation)
(situation)
SNOMED CT Model Component (metadata)
(attribute)
(core metadata concept)
(foundation metadata concept)
(link assertion)
(linkage concept)
(namespace concept)
(OWL metadata concept)
Social context (social concept)
(social concept)
-(ethnic group)
-(occupation)
-(person)
-(racial group)
-(religion/philosophy)
Special concept (special concept)
(navigational concept)
Specimen (specimen)
(specimen)
Staging and scales (staging scales)
(staging scale)
-(assessment scale)
-(tumor staging)
Substance (substance)
(substance)
Oral hemorrhage
SYN - GB English
Oral haemorrhage
SYN
Stomatorrhagia
FSN
Bleeding of mouth (disorder)
PT
Bleeding of mouth
SYN
Bleeding in mouth
FSN
Computed tomography of upper limb (procedure)
PT
CT of upper limb
SYN
FSN
Esophageal structure (body structure)
PT - US English
Esophageal structure
PT - GB English
SYN - US English
Computed tomography of upper limb
Oesophageal structure
Non-circular
Do not use the term in the definition.
Genus + Differentia
Define by broader category + distinguishing features.
Context-aware
Include notes or usage context if necessary.
1332358007 |Full schwannomatosis (disorder)|Clarity
Avoid ambiguity or overly complex language.
Conciseness
Be as brief as possible without sacrificing meaning.
Consistency
Use a consistent structure and vocabulary.
FSN: Repair of common bile duct (procedure) - the meaning
PT: Choledochoplasty -commonly understood clinical name
Choledochoplasty is marked as preferred in the US English Language Reference Set; choledochoplasty is the preferred term for this concept in US English.
Each new content request should have an FSN that conforms to spelling, language, and style guidelines. It should also have SNOMED CT parent concepts that conform to editorial guidelines and show where in the hierarchy it belongs. In the Content Request System (CRS), if the meaning of the FSN is unclear or the parent codes are not provided, authors should request the information from the submitter.
A well formed FSN includes:
Correct US spelling, not GB (General British) spelling
Singular form, not plural form
Procedures in present tense, not past tense
A semantic tag in parentheses at the end
An FSN with an approved disjunctive (although not often used) should have lower case and/or.
For example, |Traumatic and/or non-traumatic injury of back (disorder)|
An FSN should not have:
Abbreviations or acronyms * For more information, including exceptions, see the Abbreviations and acronyms section at General Naming Conventions
Hyphens
Duplicate concepts
Ambiguity
The word OR (exception for the disjunctive and/or)
Forward or backslash (/ \)
Precoordinated numeric ranges
Reference to a particular instance
Reason or indication for a procedure, unless this directly impacts the method
Exceptions that should not be amended include:
Trademark names
Latin names of organism
Scientific names
Gene names
When constructing the FSN for a disorder, finding, or procedure containing a body structure, the wording of the body structure should follow the naming convention of the body structure concept. However, it should not include the words structure or structure of.
For example,
For the body structure concept, 266005 | Structure of lower lobe of right lung (body structure)| , a procedure with this body structure is 726425007 | Lobectomy of lower lobe of right lung (procedure)|.
For the body structure concept, 74386004 | Nasal bone structure (body structure)| , a disorder concept with this body structure is 413878002 | Closed, displaced fracture of nasal bone (disorder)|.
The FSN is unique among active concepts. The SNOMED International Authoring Platform automatically creates a matching description to the FSN. Authors then determine the clinical usefulness of a synonym that matches the FSN. Those that are useful are maintained in SNOMED CT; those that are not useful are removed. The Authoring Platform displays a warning when the matching description is removed; however, this does not prevent the author from saving the concept.
The FSN should provide a linguistic representation of the concept in an unambiguous way. It is considered an anchor for the representation of meaning of a concept, to which modelers can refer, when assigning a logic-based definition. The FSN does not necessarily follow the usual phrasing used in clinical practice; it may be phrased differently and may be longer and more fully spelled out in order to represent the meaning as clearly as possible and globally communicate the intended meaning of the concept.
The characters comprising the description, as well as case significance, must be taken into account to provide for a unique FSN. Uniqueness maintained through case sensitivity is handled by Case Significance. It is possible to alter the semantics of concepts whose FSN uniqueness depends upon case significance.
For example,
The two referenced concepts above could easily be mistaken for duplicates if not for varying case sensitivity indicators that demarcate each concept's uniqueness.
A single term may have more than one meaning. Therefore, FSNs should be checked for ambiguity.
For example, immunosuppression may mean the state of being immunosuppressed, or it may mean the application procedure of immunosuppressive therapy.
The following FSNs are clear and acceptable.
For example,
The following FSNs are ambiguous, and the concept should be inactivated.
For example,
Standing in water side toward (finding); does not indicate which side of what is toward what
Lumbar ache - renal (finding); does not convey whether the lumbar ache is specifically a renal etiology or is merely located in the renal area
Minor changes to an FSN are allowed without inactivation of the concept. When making a minor change to an FSN, a new description must be created and the old description must be inactivated. While the description ID will change, the concept ID remains the same. FSN changes cannot change the meaning of the FSN. Minor changes include:
Changing case; i.e. capitalizing, or changing from upper to lower case
Changing punctuation
Changing spelling
Replacing an acronym with its expansion (only if it is commonly understood and not ambiguous)
Expanding an abbreviation
Correcting word order without changing the meaning (only for an error)
Correcting typos
Removing articles, such as 'the'
Where a change to the FSN does not result in a change to the preferred term
Aligning with editorial policy, e.g. changing appendectomy to excision of appendix*
Where an active concept requires an update to the FSN to conform to current editorial guidance, this may result in duplication with the FSN on an inactive concept.
In this scenario:
The current active concept should be retained. There is no requirement to inactivate the currently active concept and reactivate the inactive concept.
For the concept that is inactive, the inactivation reason should be updated to ‘Duplicate’ and the association type ‘SAME_AS’ to the active concept with the same FSN.
For example,
Concept 27215002 had an FSN of Uterine inversion (disorder). Editorial policy instructs this to be formatted as Inversion of uterus (disorder). However, an inactive concept of 156232008 |Inversion of uterus (disorder)| already exists with that FSN. 156232008 |Inversion of uterus| is named correctly but has been inactive since 2002. In this case, the concept 27215002 should remain active with its FSN updated.
The inactive concept, 156232008 |Inversion of uterus|, should be checked to ensure its inactivation reason is ‘Duplicate’ and the Association type ‘SAME_AS’ to the active concept 27215002 with the same FSN.
For circumstances where a new concept duplicates an inactive concept with the same FSN, the inactive concept should be reactivated rather than adding a new concept.
Some FSN changes are necessary for style consistency; again, changes are only acceptable if the meaning does not change.
They may include changing:
Semantic tag type within a single top-level hierarchy
For example,
A 'finding' tag to a 'disorder' tag
A 'procedure' tag to a 'regime/therapy' tag
When changing a concept's semantic tag within the same top-level hierarchy, use the description inactivation reason of Non-conformance to editorial policy.
Changing a concept's semantic tag to navigational concept
A substance or product name to reflect the International Nonproprietary Name (INN)
The current scientific name of an organism (only applies to 410607006 |Organism (organism)| hierarchy)
Major changes to FSNs require inactivation of the concept. The following are examples of major changes, when:
Changing the FSN changes the meaning
FSN is ambiguous
FSN meaning is more specific than the modeling; inactivation is determined case-by-case as this could simply be a primitive concept which cannot be defined
Moving to a different top-level hierarchy
Exception: Concept inactivation is not required for moving a concept to the navigational concept hierarchy.
Changing the common name to the scientific name
Ancestors and descendants (if any) of the concept are inconsistent with what is implied by the FSN - inactivate concepts
The FSN for a concept in the International Release is designated an International FSN. The International FSN is considered the gold standard for interpretation of the meaning of the concept, from a linguistic standpoint.
The logical definitions, represented using the concept model, should represent the same meaning. Spelling of the International FSN follows United States (US) English spelling conventions. Other English language spelling and conventions, such as Great Britain (GB) English, may be represented in preferred terms and other descriptions. They should be appropriately tagged using the Language Reference Set mechanism.
For example,
191268006 | Chronic anemia (disorder)|
FSN: Chronic anemia (disorder)
US PT: Chronic anemia
GB PT: Chronic anaemia
414545008 | Ischemic heart disease (disorder)|
FSN: Ischemic heart disease (disorder)
US PT: Ischemic heart disease
GB PT: Ischaemic heart disease
Acronyms are easily misinterpreted. For this reason, acronyms are discouraged in FSNs.
For example, the FSN should be the expanded form, Computed tomography of chest (procedure); however, as a preferred term, CT of chest (procedure) is acceptable.
If there is an unacceptable acronym in an existing FSN, the FSN DescriptionId is inactivated, and a new FSN is created (regardless of whether or not the acronym was in parentheses with the expanded form). The replacement FSN concept has the expanded description with the acronym entirely removed. Inactivating the ConceptId is not necessarily required, unless the FSN had significant ambiguity before changing it to its expanded form. For more information on acronyms, see the Abbreviations and acronyms section of General Naming Conventions.
Before any changes are made to an FSN, imported directly with an extension (local) ID, the submitter should be notified and confirmation sought that no loss of meaning has occurred. This helps to ensure that the original meaning is understood and maintained. Authors should:
Adhere to naming conventions.
Advise the submitter of changes and confirm that they are acceptable.
Check for existing concepts with the same FSN; the term may be added as a preferred term or synonym.
Changes to existing SNOMED CT concepts do not necessitate notifying the original submitter.
A term unique among active descriptions in SNOMED CT that provides the meaning of a concept in a manner that is intended to be unambiguous and stable across multiple contexts.
38194003 |Weak e phenotype (finding)|6800004 |Weak E phenotype (finding)|Benign neoplasm of clavicle (disorder)Excision of cyst of spleen (procedure)In SNOMED CT, a synonym (SYN) is a description that is an acceptable way to express the meaning of a concept in a particular language or dialect; it is a word or phrase, other than the FSN, that represents a concept. Unlike FSNs, synonyms are not required to be unique.
Each concept may have one or more synonyms.
For example,
US English synonyms for 22298006 | Myocardial infarction (disorder)| are:
Myocardial infarction
Cardiac infarction
Heart attack
Infarction of heart
MI - myocardial infarction
Myocardial infarct
A synonym may not change to, i.e. replace, an existing FSN.
When a synonym is more specific than the FSN, it does not have the same meaning, and should be inactivated. The description inactivation value of 723278000 |Not semantically equivalent component (foundation metadata concept)| is used.
For example,
FSN: Removal of device (procedure)
SYN: Removal of prosthetic device (procedure)
Removal of prosthetic device has a more specific meaning than Removal of device ; therefore, the synonym Removal of prosthetic device should be inactivated from the concept.
When a synonym is more general than the FSN, and there is no context in which it has the same meaning as the FSN, the synonym should be inactivated. The description inactivation value of 723278000 |Not semantically equivalent component (foundation metadata concept)| is used.
For example,
FSN: Sprain (morphologic abnormality)
SYN: Joint injury - more general meaning than the FSN
Joint injury has a more general meaning than Sprain ; therefore, the synonym Joint injury should be inactivated from the concept.
Two active descriptions in the same hierarchy should not share the same term unless the language is different.
Where two or more concepts have the same description(s), both concepts must be checked to determine whether the concepts are in fact duplicates. If the concepts are duplicates, one concept is inactivated with the inactivation reason of SAME_AS and historical association to the other concept.
A description with a single meaning may be erroneously associated with more than one concept. If the concepts are not duplicates, the description should be retained with only one of the concepts and inactivated on the other(s).
Some descriptions have more than one meaning when this is considered in conjunction with the hierarchy the concept is situated in. The purpose of the semantic tag is to disambiguate concepts that have the same commonly used word or phrase. Therefore, there are circumstances where the same description can be appropriate, either as the preferred term or synonym, for concepts in different hierarchies.
The most common example of this is clinical finding/disorder/morphologic abnormality hierarchies where the disorder and the associated morphology may use the same descriptions.
For example,
Preferred term - Intravascular large B-cell lymphoma
Preferred term - Intravascular large B-cell lymphoma
The morphologic abnormality concept is used as the value for associated morphology to sufficiently define the disorder concept.
Furthermore, the same description might refer to an action for a procedure, a morphologic abnormality to describe an abnormal body structure, or a clinical finding/disorder describing a normal/abnormal observation or clinical state, judgement, or assessment.
For example,
Abrasion is a description for:
Synonym Abrasion
Preferred term Abrasion
Preferred term Abrasion
Further examples below illustrate where a duplicate description may be published on separate concepts in different hierarchies, and these are clinically accurate and required to present clinically relevant information.
Synonym - 24 hour urine volume
Synonym - 24 hour urine volume
Preferred term - Acid fast stain
Synonym - Acid fast stain
Preferred term - Acriflavine stain
Synonym - Acriflavine stain
Preferred term - Activated coagulation factor
Preferred term - Activated coagulation factor
Preferred term - Ankle brachial pressure index
Preferred term - Ankle brachial pressure index
Where the case significance is deliberately different for descriptions across one or more concept(s), these differences may be included for clinical relevance and are not duplicate descriptions.
For example,
Synonym - Alpha-N-acetylglucosaminidase deficiency [cI]
Synonym - alpha-N-acetylglucosaminidase deficiency [CS]
When creating a duplicate description for concepts in two separate hierarchies, it is important to check that the descriptions are truly synonymous with the FSN. There may be cases where an additional word(s) may remove the duplication and reduce the risk of adding a broader or narrower description than the FSN. Where it is not possible to do this, it is acceptable for these duplicate descriptions to coexist across different hierarchies.
1157162007 |Intravascular large B-cell lymphoma (disorder)|399648005 |Intravascular large B-cell lymphoma (morphologic abnormality)|8420001 |Abrasion (procedure)| 400061001 |Abrasion (morphologic abnormality)|399963005 |Abrasion (disorder)|365680006 |Finding of 24 hour urine volume (finding)|271068005 |24 hour urine sample volume measurement (procedure)|708056006 |Acid fast stain technique (qualifier value)|67122001 |Acid fast stain method (procedure)|17693003 |Acriflavine stain (substance)|406805004 |Acriflavine stain method (procedure)|734785000 |Activated coagulation factor (disposition)|116188009 |Activated coagulation factor (substance)|446841001 |Ankle brachial pressure index (observable entity)|401221002 |Ankle brachial pressure index (procedure)|59990008 |Mucopolysaccharidosis III-B (disorder)|