Note
The concept (G-C1C6, SRT, "Quantity"), lacking a formal definition in SNOMED, is assumed in
this usage to be synonymous with the concept defined for "quantity" in Joint Committee
for Guides in Metrology (JCGM), International Vocabulary of
Metrology, Basic and General Concepts and Associated Terms (http://www.bipm.org/utils/common/documents/jcgm/JCGM_200_2012.pdf); the
definition is "property of a phenomenon, body, or substance, where the property has a
magnitude that can be expressed as a number and a reference". That document further
distinguishes a "physical quantity", "chemical quantity", and "biological quantity",
though no such distinction is implied here, and "quantity" is assumed to be all
inclusive.