Relative mass concentration (rel.mass c.) - Dynamic NPU Manual

Relative mass concentration (rel.mass c.)


Rel.mass c.

Definition in words

Mass concentration of component B in system 1 divided by mass concentration of component B in system 2

Note: System 1 is not related to system 2

Definition by equation

Systematic terms

Relative mass concentration of component B in system 1
Ratio scale
  • Value sets are positive numerical values
  • Algebraic operations are allowed (a=nb; a≠nb)
Numerical values from 0-∞


10-6, 10-3, 1 (one), 103, 106, etc.

The unit “1” (one) is ommited in the NPU syntax.


Ferard G, Dybkaer R, Fuentes-Arderiu X. Compendium of Terminology and Nomenclature of Properties in Clinical Laboratory Sciences : Recommendations 2016. 1 ed: Royal Society of Chemistry; 2016. 182 p. Doi:10.1039/9781782622451.

Laboratory field


Clinical Chemistry

Example 1
Generic abbreviated form NPU19659 Csf—Albumin; rel.mass c.(Csf/P) = ? × 10-3
Full form with a result NPU19659 Cerebrospinal fluid—Albumin; relative mass concentration(Cerebrospinal fluid/Plasma) = 5.7 × 10-3
Abbreviated form with a result NPU19659 Csf—Albumin; rel.mass c.(Csf/P) = 5.7 × 10-3
Written expression The relative mass concentration of albumin in Mr. Smith’s Cerebrospinal fluid is [5.7] × 10-3. The calculation is performed by dividing mass concentration of albumin in Mr. Smith’s cerebrospinal fluid with mass concentration of albumin in Mr. Smith’s plasma.
Example 2
Generic abbreviated form NPU29225 Csf—Prostaglandin-D-synthase; rel.mass c.(Csf/P) = ?
Full form with a result NPU29225 Cerebrospinal fluid—Prostaglandin-D-synthase; relative mass concentration(Cerebrospinal fluid/Plasma) = 0.24 x one
Abbreviated form with a result NPU29225 Csf—Prostaglandin-D-synthase; rel.mass c.(Csf/P) = 0.24
Written expression The relative mass concentration of Prostaglandin-D-synthase in Mr. Smith’s Cerebrospinal fluid is [0.24]. The calculation is performed by dividing mass concentration of Prostaglandin-D-synthase in Mr. Smith’s cerebrospinal fluid with mass concentration of Prostaglandin-D-synthase in Mr. Smith’s plasma.


NPU database, and
  • Kind-of-property

    • Nominal kind-of-property

    • Kind-of-quantity

      • Unitary kind-of-quantity

        • Rational unitary kind-of-quantity

          • Relative mass concentration


  • Dybkaer R. Concept system on ‘quantity’: formation and terminology. Accredit Qual Assur. 2013;18(3):253-60.
  • Dybkaer R. ISO terminological analysis of the VIM3 concepts ‘quantity’ and ‘kind-of-quantity’. Metrologia. 2010;47(3):127-34.
Date Term Note
1996-01-01 Relative mass concentration Term established