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), strings (e.g. "PANADOL"), and booleans (e.g. TRUE1 .

The expression shown below uses both concept values and concrete values to represent a product containing precisely 500 milligram amoxicillin per oral tablet. 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 numerator and denominator are represented using a numeric value. Furthermore, the |Count of base of active ingredient| also uses a numeric value, and represents the number of substances that is the part of the ingredient that the strength of a given product is based upon. The numeric values are indicated in the expression by the preceding '#' symbol (e.g. #500).

The expression below represents a medicinal product that contains precisely chlorhexidine diacetate 10 milligrams per gram conventional release cutaneous powder. Boolean and string-based concrete values may also be used2 . For example, the expression below represents a tablet containing 500 mg of paracetamol with a trade name (or brand name) of "PANADOL"3 . And the expression below represents an Irbesartan 150 mg tablet that is eligible for reimbursement through the national benefit scheme (of the given country)4 .

Ref Notes
1 Boolean values are not permitted in the SNOMED CT International edition.
2 Boolean and 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 adequately defined using a concept value.
3 Concrete values of type string are case sensitive and compared using the Unicode Collation Algorithm (
4 The concept 859999999102 | is in national benefit scheme | is a fictitious attribute used here to illustrate boolean values.