Amount-of-substance of a component divided by the mass of the system.
- The term @C01209@ is recommended for clinical chemistry, ISO uses 'substance'.
- The term @S06234@ is recommended for clinical chemistry, ISO uses @M03949@.
- Use of the term level as a synonym for content is deprecated.
- In describing a quantity, @C01296@ must be clearly differentiated from @C01222@.