A structured combination of one or more concept identifiers that represents an idea.

Notes

• An expression containing a single concept identifier is referred to as a precoordinated expression. An expression that contains two or more concept identifiers is a postcoordinated expression.
• The syntax used to represent SNOMED CT expressions is called the SNOMED CT compositional grammar and is formally defined in the Compositional Grammar - Specification and Guide.
• The concept identifiers in a postcoordinated expression are related to one another in accordance with rules expressed in the SNOMED CT Concept Model. These rules allow an expression to refine the meaning of a concept by applying more specific values to particular attributes of a more general concept.

Example

• The expression  284196006 | :363698007=770850006|  represents a burn to the skin of the left index finger. 

• An expression can also include the terms related to each of the identified concepts as shown below:

  284196006 |burn of skin| : 363698007 |finding site| = 770850006 |Skin structure of left index finger|

  Alternatives

Alternatives

• Expression

Related Links

• Glossary
  • precoordinated expression
  • postcoordinated expression
  • focus concept
  • refinement
  • context wrapper
• SNOMED computable languages
  • SNOMED CT compositional grammar
  • SNOMED CT expression constraint
  • SNOMED CT template
• Specification
  • Compositional Grammar Specification and Guide