New attributes that are added to the SNOMED CT concept model (or to a SNOMED CT extension) may require their value to be concrete. Concrete values include integers (e.g. 500), decimals (e.g. 2.75) and strings (e.g. "PANADOL").
The expression shown below uses both concept values and concrete values to represent a capsule that contains 500 mg of amoxicillin
1 . In this case, the dose form, the active ingredient, the basis of strength substance and the strength unit all use a concept as their value, while the strength magnitude is represented using a numeric value. The numeric value is indicated in the expression by the preceding '#' symbol (e.g. #500).
The expression below represents an oral solution that contains 0.083 % albuterol.
String-based concrete values may also be used. For example, the expression below represents a tablet containing 500 mg of paracetamol with a trade name (or brand name) of "PANADOL"
Please note that string-based concrete values should be used with caution. Care must be taken to only use these in situations in which the clinical meaning cannot be defined using a concept value.
Please note that these example expressions are based on a hypothetical drug concept model, and are not intended to reflect any specific drug model. In these expressions, the SNOMED CT identifiers created with the '9999999' namespace are for example only, and should not be used in a production environment.
Concrete values of type string are case sensitive and compared using the Unicode Collation Algorithm (http://www.unicode.org/reports/tr10/).