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General Naming Conventions

In addition to the general naming conventions below, please also see any applicable naming conventions for specific hierarchies in their respective Domain Specific Modeling.

Generally, names should:

Be consistent and reproducible
Follow natural or human language when possible
Be unambiguous to users
Be clear for translation purposes

Naming conventions should not be based on word order preferences (e.g. to facilitate search or display). Creating multiple word order variants for these purposes is outside the scope of the International Release of SNOMED CT .

Descriptions should not include articles such as a, an, and the. There are legacy descriptions that contain articles such as the that will be corrected over time.

For example,
- Use description of Neoplasm of respiratory tract (disorder) , not Neoplasm of the respiratory tract (disorder)
- Use description of Rupture of diaphragm (disorder) , not Rupture of the diaphragm (disorder)

Abbreviations are shortened forms of words or phrases. An acronym is a specific type of abbreviation formed from the initial letters of words and is sometimes pronounced as a word (e.g. AIDS for Acquired Immunodeficiency Syndrome ; NICU for Neonatal Intensive Care Unit). Neither abbreviation nor acronym is permitted in a fully specified name (FSN).

For example
- Sperm is a shortened form of the word spermatozoa. The proper term of spermatozoa should be used in the FSN, while sperm can be used as a synonym.

Abbreviations and acronyms are allowed in a preferred term or synonym when followed by the term expansion. If the abbreviation or acronym stands alone (meaning, no additional terms are included; the letters represent the entire meaning of the description without any other text), it is followed by a space, a hyphen, and another space, then the expanded term. The first word after the hyphen should be lower case as per usual capitalization rules.

For example,
- 30549001 |Removal of suture (procedure)| has a synonym of |ROS - removal of suture|
- 24526004 |Inflammatory bowel disease (disorder)| has a synonym of |IBD - inflammatory bowel disease|

If the abbreviation or acronym forms only part of the description's meaning, it is followed by a space, then the expanded term in parentheses. The first word in the parentheses should be lower case as per usual capitalization rules.

For example,
- 140031000119103 |Acute nontraumatic kidney injury (disorder)| has a synonym of Nontraumatic AKI (acute kidney injury)

Official names of organism, which is represented as organism preferred term, may include abbreviations. The abbreviations do not need to be accompanied by the fully expanded term.

For example,
- 448945001 |Campylobacter lari subspecies lari (organism)| has a synonym of Campylobacter lari subsp. Lari

Abbreviated organism part names are allowed in a preferred term (and other synonyms). The abbreviations do not need to be accompanied by the fully expanded term

For example,
- 24771000087106 |Antigen of Streptococcus pneumoniae Danish serotype 1 capsular polysaccharide conjugated to Corynebacterium diphtheriae cross-reacting material 197 protein (substance)| has a synonym |Streptococcus pneumoniae Danish serotype 1 capsular polysaccharide antigen conjugated to Corynebacterium diphtheriae CRM197 protein| that includes CRM197 which is the abbreviated form for cross-reacting material.

The preferred term for allergen components in the Substance hierarchy follows the rules established by the World Health Organization/ International Union of Immunological Societies Nomenclature Sub Committee: allergen names consist of the first three letters from the genus, one letter from the species epithet, followed by an Arabic numeral. e.g. 1157148000 |Arachis hypogaea 2 protein (substance)| has a preferred term of "Ara h 2".

An acronym is allowed in an FSN when it has become a word in its own right, i.e. included in dictionaries; understood without expansion to its original full form.

For example,
- 122456005 | Laser device (physical object)| uses the term "laser", which originated as an acronym for "light amplification by stimulated emission of radiation"

The preferred term for imaging procedures involving imaging modalities commonly referred to by an acronym (such as CT, MRI, SPECT, PET) omits the expanded term after the acronym.

For example,
- |CT of head| is the preferred term for | Computed tomography of head (procedure)|

Acronyms in rare and genetic diseases have been included for the concepts as part of the Orphanet project that do not include expansion of the abbreviation, as some of the diseases are commonly known by the acronym.

For example,
- 1: GLOW syndrome is a synonym of 782722002 |Global developmental delay, lung cysts, overgrowth, Wilms tumor syndrome (disorder)|. Although the FSN and other descriptions have full expansions, there is a description included for |GLOW syndrome|, which does not further delineate the GLOW acronym.
- 2: BRESEK syndrome is a synonym of 717945001 |Brain anomaly, severe mental retardation, ectodermal dysplasia, skeletal deformity, ear anomaly, kidney dysplasia syndrome (disorder)|. Although the FSN and other descriptions have full expansions, there is a description included for |BRESEK syndrome|, which does not further delineate the BRESEK acronym.

Based on recommendation by the International Protein Nomenclature Guidelines, an abbreviation may be part of a protein name:

For example,
- 1222711007 |ALK tyrosine kinase receptor (substance)| where ALK stands for Anaplastic lymphoma kinase
- 1222739008 |DNA mismatch repair protein Msh6 (substance)| where DNA stands for deoxyribonucleic acid

A synonym may contain an abbreviation without expansion for a description containing multiple chemical substances whose expansion may potentially impact usability or clinical safety; the synonym should be supported by its use in product information.

For example,
- 1984901000001119 HYNIC-[D-Phe1, Tyr3-octreotide] TFA salt
  - Expanding the four abbreviations found within the synonym above would yield confusing results. Additionally, the synonym is referenced in the summary of product characteristics.

Eponyms are names that are derived from proper names (usually the person who made the discovery or created the original description). It is neither desirable nor possible, to completely avoid using eponyms in a medical terminology. They are found in many areas of medical terminology, including anatomic structures, morphologic abnormalities, diseases, findings, and procedures (e.g. Rutherford Morison's pouch, vein of Galen, Aschoff body, Kell blood group, Down syndrome, Moro reflex, and Whipple procedure).

Fully specified names (FSN) should be full descriptions, whereas synonyms may be eponymous terms.

For example,
- Structure of great cerebral vein (body structure) has the synonym |Vein of Galen|
- Complete trisomy 21 syndrome (disorder) has the synonym |Down syndrome|
- Pancreaticoduodenectomy (procedure) has the synonym |Whipple procedure|

Eponymous descriptions should not include an apostrophe or final s, unless the name normally ends in s.

For example,
- Down syndrome, a synonym for |Complete trisomy 21 syndrome (disorder)|
- Meigs syndrome (disorder)

When common usage requires it, there should be at least one description that has the apostrophe s. For descriptions with a possessive apostrophe where the name normally ends in s, the apostrophe should follow the s.

For example,
- Alzheimer's disease (disorder)
- Bowen's disease (disorder)
- Meigs' syndrome (disorder)

It is permitted and encouraged to include eponyms as descriptions (non-FSN descriptions) whenever they are understandable, reproducible, and useful in a given context.

Exceptions require careful consideration since eponyms meanings may change over time. They are allowed when:

The full description is exceptionally long and unwieldy (e.g., Hemi-Fontan operation (procedure) instead of bidirectional Glenn shunt with end-to-side anastomosis of proximal superior vena cava to right pulmonary artery with isolation from right atrium).
The eponym is the only precise, clinically relevant name available.
A non-eponymous name would necessarily be vague or subject to misinterpretation (e.g., Hodgkin lymphoma, Burkitt lymphoma).
A brand name has become an eponym. In this case, some brand names have come to stand for a category of product and not the particular brand itself (examples in US English: Kleenex, Band-Aid, Popsicle, Dacron, and Teflon).

When constructing an FSN, the preposition 'of' is preferred over using the preposition 'in' to describe the morphology of an anatomic structure.

For example,
- Cyst of scalp should be used for the FSN and not Cyst in scalp because the latter may indicate a morphology within a layer of the structure, whereas 'of' indicates the morphology is within the region of the anatomic structure.

The foundation hierarchies are body structure, substance, organism, physical object, and product. These hierarchies underpin the naming and modeling of other hierarchies. When creating the descriptions for a concept that name an entity from a foundation hierarchy, such as a disorder concept referencing a body structure, the conventions that are applied for naming the entity in the foundation hierarchy should be used in the non-foundation hierarchy descriptions as well.

For example,
- 11218009 | Infection caused by Pseudomonas aeruginosa (disorder)|
  - This concept references the organism hierarchy in the causative agent of 52499004 |Pseudomonas aeruginosa (organism)| and uses that description in the FSN.
- 143491000146106 |Felis catus protein (substance)|

Descriptions should be context-neutral for foundation hierarchies. Where context is explicit for a disease or procedure, the preferred term from foundation hierarchies can be used instead.

For example,
- Procedure CT of abdomen indicates that the context of CT imaging is cross-sectional. The procedure site should be modeled with the cross-sectional abdomen. However, it is not necessary to change 'Computed tomography of abdomen (procedure)' to 'Computed tomography of cross-sectional abdomen (procedure)'. It is the same reason for the preferred term |CT of abdomen|.

Where an infection caused by a microorganism has a common name, the common name of the disease can be used in the preferred term if accompanied by the explicitly-stated organism.
When defining concepts in other hierarchies by referring to an organism, the taxonomical rank of the organism should not be included in the FSN or synonyms.
- For example,

All descriptions (FSN, PT, SYN, DEF) have a character limit of 4096 characters.

In the rare event that the character limit of the fully specified name is reached, standard naming conventions may be circumvented in order to adhere to the term string limit.

For example, the use of commas may be used instead of the word “and”.

Considerations can include language nuances, content use case, etc. The decision on which standard naming conventions to circumvent will depend on the circumstances.

Fully Specified Name

Fully specified name (FSN) definition

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.

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,

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
Hyphens
Duplicate concepts
Ambiguity

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 . 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)

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

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

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 .

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.

Semantic Tag

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.

Domain

Semantic tag

Preferred Term

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.

Synonym

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.

Definition

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.

The definition should never be contradictory to the modeling.

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 :

Principle

Explanation

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.

Case Significance

Generally, SNOMED CT descriptions begin with an upper case letter; the rest of the words in the description are lower case, except for abbreviations and proper nouns (names of people, organizations, taxonomic groups (e.g. species, genus, family)).

Case Sensitivity

Case Sensitivity Indicator

Values

Meaning

Examples

900000000000020002 | Only initial character case insensitive (core metadata concept)|

Special attention is to be paid to the possibility of altering the semantics of those concepts whose FSN uniqueness depends upon case significance.

For example,
- The subtypes of 365638007 |Finding of Rh blood group (finding)| vary in meaning depending upon the description's case of the letters c, d, and e.

SNOMED CT includes three case significance values: ci, cI, and CS. However, this range of values depends on the languages and linguistic norms. For the International Edition, where the first character of descriptions is always capitalized, the value Only initial character case insensitive (cI) is necessary. This value is not required for descriptions in extensions that do not adhere to this convention. When appropriate, it is also acceptable to limit the range to a single case significance value.

Non-taxonomic groupers, such as “Human herpes simplex virus”, are recorded with a case sensitivity indicator of Entire term case insensitive (ci).

There are cases where the authoritative resources do not have an entry for the official name of an organism. For these concepts, the associated literature is referenced for naming and case sensitivity assignments.

For example,
- “Severe acute respiratory syndrome coronavirus 2” is below species level and does not have an entry in the authoritative resource, International Committee on Taxonomy of Viruses (ICTV). Therefore, it is recorded with a case sensitivity indicator of Entire term case insensitive (ci), since the majority of references do not capitalize “severe”.

When an organism is part of the term of a concept in another hierarchy, it is capitalized. However, when the general reference to the organism is part of the term, the term in the description is not capitalized.

For example,
- 19431000 |Infective arthritis caused by Rubella virus (disorder)| - Since the Rubella virus is specified, Rubella is capitalized.
- 1857005 |Congenital rubella syndrome (disorder)| - Since rubella refers to the disease, rubella is not capitalized.

When the species Vaccinia virus (of the genus Orthopoxvirus) is specified, Vaccinia is capitalized.

For example,
- 293120003 |Adverse reaction to component of vaccine product containing Vaccinia virus antigen (disorder)|

When vaccinia is describing a condition, vaccinia is not capitalized.

For example,
- 56978007 |Generalized vaccinia (disorder)|

Numeric values will not display differently if switched between upper and lower case, so numeric values should be treated as case insensitive characters in a term.

If a description begins with a numeric value and the word following the number does not begin with a capital letter, the case sensitivity indicator is ci for Entire term case insensitive.

For example,
- The concept 33635003 | Serotonin (substance)| has the synonym, 5-hydroxytryptamine. The description is recorded in SNOMED CT in lower case, not 5-Hydroxytryptamine, but the case sensitivity indicator is ci for Entire term case insensitive.

If a description begins with a numeric value and follows with an abbreviation that contains a capital letter, the case sensitivity indicator is cl for Initial character case insensitive.

For example,
- The concept 387407006 | Tioguanine (substance)| has the synonym, 6-TG. Apply the case sensitivity indicator of cl for Only initial character case insensitive.

The case significance setting for concepts that represent formal gene names are to align with the source (usually HGNC). However, when referring to the disease caused by the gene, there is no such requirement, and the standard terming editorial guidance applies. The disorder caused by the gene should have an initial capital letter, even if the name of the disease is the same as the gene name. Exceptions are if the initial letter of the disorder is case sensitive; for example, 48449016 |tRNA|, 1402127002 |APC regulator of Wnt signaling pathway 2 gene related Sotos syndrome (disorder)|.

Special characters such as <, %, >, . , &, ^, will not display differently if switched between upper and lower case, so numeric values should be treated as case insensitive characters in a term. The rules for numeric values apply similarly to special characters.

If a description begins with a special character and the word(s) and/or symbol(s) following the special character begins with a capital letter, the case sensitivity indicator is cl for Initial character case insensitive.

For example,
- The concept
  277976001 | Less than 35 degrees C (qualifier value)| has the synonym, <35 degrees C. The description starts with a special character that is case insensitive but contains an abbreviation "C" for Celsius that is case sensitive, so the case sensitivity indicator applied to the synonym is cl for Only initial character case insensitive.

SNOMED CT descriptions representing assessment scales and staging systems should be capitalized per the name of the scale or staging system. Legacy concepts may not follow this pattern.

For example,
- Ages and Stages Questionnaires Third Edition (assessment scale)
- Fagerstrom test for nicotine dependence (assessment scale)
- National Cancer Institute histologic grading system (staging scale)

Person Naming Conventions

Patient vs Subject

The |Situation with explicit context (situation)| hierarchy is intended for concepts that explicitly include contextual information. Context can include whom the finding is about, or on whom a procedure is performed. These concepts can be used to represent different meanings, e.g., past history, family history, planned care, excluded diagnosis, etc.

In contrast, a concept in the Clinical Finding or Procedure hierarchy has a default Intended Use of the subject of the record. This context can be overridden by the information model.

For example,
- The concept |Asthma (disorder)| could be used in a family history field to represent a family history of asthma.

However, including the term subject or patient within a Clinical finding or Procedure concept prevents that concept’s context from being overridden by the information model.

For example,
- The concept |Patient immunocompromised (finding)| could not be used in a family history field to represent that a family member is immunocompromised.

Therefore, the use of patient and subject should be used only when necessary.

Descriptions should use the word subject, not patient, if required, as subject is broader than patient.

For example,

Subject refers to the subject of record, who may, in some circumstances, not be the patient.

Best practice is to create a contextless concept.

Example - finding,
- Patient unable to chew with denture (finding) - incorrect
  - Unable to chew with denture (finding) - correct
Example - procedure,

Descriptions with caregiver should be as follows:

An FSN should use caregiver as (one word).
There should be a synonym using carer.

For example,

Synonym: Carer able to cope

Punctuation and Symbols

Legacy content may not adhere to current guidelines and will be updated as resources allow.

Comma ( , )

A comma is allowed in an FSN when required for meaning or to add clarity.

For example,
- Computed tomography of head, neck, abdomen and pelvis (procedure)

A comma is not allowed to change sort order for use in the search function.

Unacceptable example,
- Frostbite, acute

Eponymous descriptions should not include an apostrophe or final s, unless the name normally ends in s. With rare exception, a concept with an eponym should have at least one description that follows this rule.

For example,
- Down syndrome, a synonym for Complete trisomy 21 syndrome (disorder)
- Sjogren syndrome (disorder)
- Meigs syndrome (disorder)

For example,
- Alzheimer's disease (disorder)
- Bowen's disease (disorder)
- Meigs' syndrome (disorder)

In protein names, a prime symbol is used to indicate the cleavage location on a substrate and to distinguish different subunits with the same notation. SNOMED CT uses the single quote character, also known as apostrophe, to represent prime.

For example,
- 80222004 |5'-nucleotidase (substance)|

The international edition of SNOMED CT does not publish descriptions with prime symbols.

Hyphens should follow rules of style for the dialect and language in which the descriptions are used as found in such publications as the Chicago Manual of Style, the American Medical Association’s Manual of Style, a current medical dictionary, etc. Punctuation is to be used sparingly unless used to prevent ambiguity.

When a hyphen is used to join words or to separate syllables, there is no space either before or after the hyphen.

For example,
- Anti-infective agent (product)
- Zollinger-Ellison syndrome (disorder)
- Zellweger's-like syndrome (disorder)

A hyphen may be used to separate two phrases, to contrast values, or to show a relationship between two things. A hyphen should rarely be used in an FSN, because it may obscure the exact meaning of the description; the hyphen should be replaced with words that clarify the meaning.

A hyphen is used to separate an acronym from its expanded form when no other terms are included in a description.

For example,
- 30549001 |Removal of suture (procedure)| has a synonym of |ROS - removal of suture|

In general, colons should not be used in fully specified names.

Colons are allowed in the FSNs of organisms, substances, or products where the colon is part of the name. They are also allowed in ratios and in tumor stages.

For example,
- Salmonella II 43:g,t:[1,5] (organism)
- Lidocaine hydrochloride 1.5%/epinephrine 1:200,000 injection solution vial (product)
- pT3: tumor invades adventitia (esophagus) (finding)

Colons may be allowed in non-FSN descriptions.

For example, to separate an abbreviation from the rest of a name or a specimen from the finding
- Urine: turbid (finding)

A double colon ( :: ) notation is allowed in the neoplastic morphologic abnormalities (400177003 |Neoplasm and/or hamartoma (morphologic abnormality)| subhierarchy). The notation can be used to represent gene fusions; for example, BCR::ABL1 fusion.

The forward slash should not be used in FSNs. When the slash is part of the authoritative name (e.g. representation of heterozygosity in hemoglobinopathies), a hyphen (no space before or after) is used in the FSN. The forward slash, without spaces, may be used in a preferred term or synonym.

For example,
- FSN: Sickle cell-hemoglobin C disease (disorder)
  - SYN: Hemoglobin S/C disease
- FSN: Per cubic millimeter (qualifier value)

A forward slash may be used to represent units of measure, official enzyme names, and laboratory test results. They may also be used in and/or when part of FSNs. There should be no space either before or after the slash.

For example,
- Nitroglycerin 0.3mg/hr disc (product)
- Ibuprofen 5%/Levomenthol 3% gel (product)
- Milligram/deciliter haptoglobin (qualifier value)

A forward slash may be allowed in non-FSN descriptions in a variety of contexts. Some common examples of use are in acronyms with findings, and as an abbreviation meaning and/or concepts.

Protein names may contain the forward slash ‘/’ for separating multiple domains or functions:

For example, 1222712000 |Serine/threonine-protein kinase B-raf (substance)|

Certain neoplastic variants incorporate a slash in their terming (note this slash does not mean 'and' or 'and/or'). Based on pathology input, a dash can be utilized in the FSN and a slash retained in the Preferred Term for clinical usage.

For example,
- FSN: Myelodysplastic-myeloproliferative neoplasm with neutrophilia (disorder)
- PT: Myelodysplastic/myeloproliferative neoplasm with neutrophilia

The plus sign is generally discouraged for use in descriptions, and legacy content still contains this symbol. However, some uses are allowed. Plus signs may be found in the product, disposition, and substance hierarchies.

For example,
- |H+/K+-exchanging ATPase inhibitor| is an acceptable synonym for
  734582004 | Hydrogen/potassium adenosine triphosphatase enzyme system inhibitor (disposition)|.

A pair of caret symbols is used to enclose character strings that should display as superscript.

The single caret is used to represent exponents, i.e. powers of, in alignment with the Unified Code for Units of Measure (UCUM) guidance on the use of powers of ten.

For example,
- 10^3 for the third power of ten

A description cannot contain a pipe character, |. Since the | is used to indicate the beginning and end of a description, it may cause confusion.

An umlaut should only be accepted for terms that do not have equivalences in English. Synonyms without umlauts should be added to facilitate searching in English.

For example,
- 83901003 |Sjögren's syndrome (disorder)| and one of its synonyms, Sjogrens syndrome

The use of brackets " [ ] " for descriptions are allowed, including in FSN and PT.

For example,
- 114819005 |Salmonella II 43:g,t:[1,5] (organism)|
- 1222745000 |Succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial (substance)|

Other special characters <, >, &, %, $, @, # are not permitted in FSNs. All instances of FSNs with these characters should be spelled out in full text.

For example,
- FD&C Yellow #2 should be FD and C Yellow Number Two

The characters &, %, and # are permitted in preferred terms or synonyms.

Sentence Types

Concepts should be names or short noun phrases. Full statements or sentences are unacceptable.

Procedure concepts should not contain phrases that can be categorized as a sentence function type, i.e., imperative, declarative, interrogative, or exclamatory. A procedure description should be a noun phrase that names the procedure, and should not contain information that it was done, or is to be ordered, carried out, or planned.

For example,
- 11227005 | Excision of ganglion of tendon sheath of hand (procedure)| is a noun phrase giving the proper description for the procedure
Unacceptable example,
- Hand tendon ganglion excised (situation) indicates the procedure was done, as a past tense declarative statement

This is a situation with explicit context, not a procedure.

US vs. GB English

All fully specified names (FSN) should be represented in US English. When there is a difference between the US and GB spelling, there should be US and General British (GB) preferred terms (PT) and/or synonyms (SYN).

For example:
- FSN: Benign tumor of endocrine pancreas (disorder)
- PT-US: Benign tumor of endocrine pancreas
- PT-GB: Benign tumour of endocrine pancreas

References for Spelling

References

Notes

SNOMED CT may include (or add) more than one description, each with a different spelling for a given concept. That is, if the above references provide evidence of acceptability in the dialects for which they are being added.

For spelling of preferred terms in a dialect, where the reference sources provide multiple options, a judgment about the most common spelling may be needed. This may be determined by reviewing journal articles containing the word in question.

Articles should be from highly cited journals, e.g BMJ (for British English) or NEJM or JAMA (for US English).
For concepts that are not clinical, appropriate scientific journals should be consulted, e.g. Science (US publisher) or Nature (UK publisher).

Fetal is the preferred term in both the US and GB language reference sets. Fetal is acceptable in GB synonyms. Foetal is not acceptable for US language but acceptable for GB language.

The terms sulfate and sulphate refer to salts or esters of sulfuric acid. Sulfate is the preferred international spelling in IUPAC and GSRS. However, sulphate is the traditional British English spelling. SNOMED CT uses sulfate in the FSN and the PT. A synonym with sulphate is added as acceptable to GB English but unacceptable to US English.

Numbers and Numeric Ranges

Roman numerals versus Arabic numbers

Use the most common representation found in literature for the fully specified name. Use the alternative representation as a synonym, if it is also represented in the literature. If neither representation is common, use the Arabic representation.

For example, in the AMA Manual of Style, cancer stages are expressed with the use of capital Roman numerals: stage I, stage II, stage III, stage IV. The term, "stage 0", usually indicates carcinoma in situ. Histologic grades are expressed with Arabic numerals, e.g., grade 2.

Numeric ranges

In general, content that depends on numeric ranges should not be used for precoordination.

For example,
- There may be too many possibilities
  - A finding of number of lesions might have ranges of 1, 2 to 5, and greater than 5; 1 to 2, 3 to 10, and greater than 10, etc.
- There may be possible changes to reference ranges or systems of units
  - The normal serum sodium concentration is usually defined as 135 to 145 mEq/L. Low serum sodium should not use the phrase serum sodium less than 135 mEq/L; it should use a phrase such as serum sodium concentration below reference range.
  - A body mass index (BMI) score as an indicator of obesity

Fully Specified Name

Fully specified name (FSN) definition

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.

For example,

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.

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
Hyphens
Duplicate concepts
Ambiguity

Exceptions that should not be amended include:

Trademark names
Latin names of organism
Scientific names
Gene names

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)|.

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

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)

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,

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

For example,

191268006 | Chronic anemia (disorder)|
- FSN: Chronic anemia (disorder)
- US PT: Chronic anemia
- GB PT: Chronic anaemia

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.

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.

General Naming Conventions

In addition to the general naming conventions below, please also see any applicable naming conventions for specific hierarchies in their respective Domain Specific Modeling.

Generally, names should:

Be consistent and reproducible
Follow natural or human language when possible
Be unambiguous to users
Be clear for translation purposes

Descriptions should not include articles such as a, an, and the. There are legacy descriptions that contain articles such as the that will be corrected over time.

For example,
- Use description of Neoplasm of respiratory tract (disorder) , not Neoplasm of the respiratory tract (disorder)
- Use description of Rupture of diaphragm (disorder) , not Rupture of the diaphragm (disorder)

For example
- Sperm is a shortened form of the word spermatozoa. The proper term of spermatozoa should be used in the FSN, while sperm can be used as a synonym.

For example,
- 30549001 |Removal of suture (procedure)| has a synonym of |ROS - removal of suture|
- 24526004 |Inflammatory bowel disease (disorder)| has a synonym of |IBD - inflammatory bowel disease|

For example,
- 140031000119103 |Acute nontraumatic kidney injury (disorder)| has a synonym of Nontraumatic AKI (acute kidney injury)

Official names of organism, which is represented as organism preferred term, may include abbreviations. The abbreviations do not need to be accompanied by the fully expanded term.

For example,
- 448945001 |Campylobacter lari subspecies lari (organism)| has a synonym of Campylobacter lari subsp. Lari

Abbreviated organism part names are allowed in a preferred term (and other synonyms). The abbreviations do not need to be accompanied by the fully expanded term

For example,
- 24771000087106 |Antigen of Streptococcus pneumoniae Danish serotype 1 capsular polysaccharide conjugated to Corynebacterium diphtheriae cross-reacting material 197 protein (substance)| has a synonym |Streptococcus pneumoniae Danish serotype 1 capsular polysaccharide antigen conjugated to Corynebacterium diphtheriae CRM197 protein| that includes CRM197 which is the abbreviated form for cross-reacting material.

An acronym is allowed in an FSN when it has become a word in its own right, i.e. included in dictionaries; understood without expansion to its original full form.

For example,
- 122456005 | Laser device (physical object)| uses the term "laser", which originated as an acronym for "light amplification by stimulated emission of radiation"

The preferred term for imaging procedures involving imaging modalities commonly referred to by an acronym (such as CT, MRI, SPECT, PET) omits the expanded term after the acronym.

For example,
- |CT of head| is the preferred term for | Computed tomography of head (procedure)|

For example,
- 1: GLOW syndrome is a synonym of 782722002 |Global developmental delay, lung cysts, overgrowth, Wilms tumor syndrome (disorder)|. Although the FSN and other descriptions have full expansions, there is a description included for |GLOW syndrome|, which does not further delineate the GLOW acronym.
- 2: BRESEK syndrome is a synonym of 717945001 |Brain anomaly, severe mental retardation, ectodermal dysplasia, skeletal deformity, ear anomaly, kidney dysplasia syndrome (disorder)|. Although the FSN and other descriptions have full expansions, there is a description included for |BRESEK syndrome|, which does not further delineate the BRESEK acronym.

Based on recommendation by the International Protein Nomenclature Guidelines, an abbreviation may be part of a protein name:

For example,
- 1222711007 |ALK tyrosine kinase receptor (substance)| where ALK stands for Anaplastic lymphoma kinase
- 1222739008 |DNA mismatch repair protein Msh6 (substance)| where DNA stands for deoxyribonucleic acid

For example,
- 1984901000001119 HYNIC-[D-Phe1, Tyr3-octreotide] TFA salt
  - Expanding the four abbreviations found within the synonym above would yield confusing results. Additionally, the synonym is referenced in the summary of product characteristics.

Fully specified names (FSN) should be full descriptions, whereas synonyms may be eponymous terms.

For example,
- Structure of great cerebral vein (body structure) has the synonym |Vein of Galen|
- Complete trisomy 21 syndrome (disorder) has the synonym |Down syndrome|
- Pancreaticoduodenectomy (procedure) has the synonym |Whipple procedure|

Eponymous descriptions should not include an apostrophe or final s, unless the name normally ends in s.

For example,
- Down syndrome, a synonym for |Complete trisomy 21 syndrome (disorder)|
- Meigs syndrome (disorder)

For example,
- Alzheimer's disease (disorder)
- Bowen's disease (disorder)
- Meigs' syndrome (disorder)

It is permitted and encouraged to include eponyms as descriptions (non-FSN descriptions) whenever they are understandable, reproducible, and useful in a given context.

Exceptions require careful consideration since eponyms meanings may change over time. They are allowed when:

The full description is exceptionally long and unwieldy (e.g., Hemi-Fontan operation (procedure) instead of bidirectional Glenn shunt with end-to-side anastomosis of proximal superior vena cava to right pulmonary artery with isolation from right atrium).
The eponym is the only precise, clinically relevant name available.
A non-eponymous name would necessarily be vague or subject to misinterpretation (e.g., Hodgkin lymphoma, Burkitt lymphoma).
A brand name has become an eponym. In this case, some brand names have come to stand for a category of product and not the particular brand itself (examples in US English: Kleenex, Band-Aid, Popsicle, Dacron, and Teflon).

When constructing an FSN, the preposition 'of' is preferred over using the preposition 'in' to describe the morphology of an anatomic structure.

For example,
- Cyst of scalp should be used for the FSN and not Cyst in scalp because the latter may indicate a morphology within a layer of the structure, whereas 'of' indicates the morphology is within the region of the anatomic structure.

For example,
- 11218009 | Infection caused by Pseudomonas aeruginosa (disorder)|
  - This concept references the organism hierarchy in the causative agent of 52499004 |Pseudomonas aeruginosa (organism)| and uses that description in the FSN.
- 143491000146106 |Felis catus protein (substance)|

Descriptions should be context-neutral for foundation hierarchies. Where context is explicit for a disease or procedure, the preferred term from foundation hierarchies can be used instead.

For example,
- Procedure CT of abdomen indicates that the context of CT imaging is cross-sectional. The procedure site should be modeled with the cross-sectional abdomen. However, it is not necessary to change 'Computed tomography of abdomen (procedure)' to 'Computed tomography of cross-sectional abdomen (procedure)'. It is the same reason for the preferred term |CT of abdomen|.

Where an infection caused by a microorganism has a common name, the common name of the disease can be used in the preferred term if accompanied by the explicitly-stated organism.
When defining concepts in other hierarchies by referring to an organism, the taxonomical rank of the organism should not be included in the FSN or synonyms.
- For example,

All descriptions (FSN, PT, SYN, DEF) have a character limit of 4096 characters.

In the rare event that the character limit of the fully specified name is reached, standard naming conventions may be circumvented in order to adhere to the term string limit.

For example, the use of commas may be used instead of the word “and”.

Considerations can include language nuances, content use case, etc. The decision on which standard naming conventions to circumvent will depend on the circumstances.

General Naming Conventions

Fully Specified Name

Semantic Tag

Preferred Term

Synonym

Definition

Case Significance

Case Sensitivity

Person Naming Conventions

Patient vs Subject

Punctuation and Symbols

Comma ( , )

Sentence Types

US vs. GB English

Numbers and Numeric Ranges

Roman numerals versus Arabic numbers

Numeric ranges

Sentence Types

Semantic Tag

Fully Specified Name

Unique

Unambiguous

Changes to FSN

Minor Changes - Only the FSN changes but not the concept

*Updating an FSN to align with editorial policy

Major Changes - When to inactivate the concept

International FSNs

Acronyms

Imported FSNs

US vs. GB English

Principles for selecting preferred spelling variants

Fetal vs. Foetal

Sulfate vs. Sulphate

Person Naming Conventions

Patient vs Subject

Caregiver vs Carer

Case Significance

Case Sensitivity

Extensions

Organism naming

Vaccinia

Numeric values

Genes and genetic diseases

Special characters

Assessment scales and Staging systems

Punctuation and Symbols

Comma ( , )

Apostrophe ( ' )

Prime symbol ( ′ )

Hyphen ( - )

Colon ( : )

Exceptions

Double Colon (::)

Forward slash ( / )

Exceptions

Plus sign ( + )

Caret symbol ( ^ )

Pipe character ( | )

Umlaut ( ¨ )

Brackets ( [ ] )

Other Special Characters ( <, >, &, %, $, @, # )

General Naming Conventions

Preferred Term

Articles

Abbreviations and acronyms

Exceptions

Eponyms

Exceptions

Preferred prepositions

Foundation hierarchies referenced in other hierarchy descriptions

Exceptions

Description Length Limit

Synonym

Nonsemantic synonyms

Narrower synonym

Broader synonym

Duplicate descriptions for concepts within the same hierarchy

Duplicate descriptions for concepts in different hierarchies

Examples

Finding vs Procedure