Arbitrary mass concentration (arb.mass c.) - Dynamic NPU Manual

Arbitrary mass concentration (arb.mass c.)


Arb.mass c.

Definition in words

Arbitrary mass concentration of component B in system 1

Definition by equation

Note 1: kprocedure is a constant defined by the measurement procedure (there is an approximately proportionality to a kind-of-quantity from the International System of Quantities).

Result type

Rational scale
  • Value sets are positive numerical values
  • Numerical values from 0-∞
  • Algebraic operations are allowed
  • Possible comparison of values (a=nb; a≠nb)


International unit (IU) or procedure defined unit (p.d.u.) (non-SI units)

Special rule(s) in the NPU syntax

Component B is termed according to the International Enzyme Nomenclature (see Medical and metrological vocabulary).

“Procedure” is stated in the specification to the kind-of-property in the NPU definition.

“Procedure” indicates that the measurement procedure must be stated somewhere else than the NPU code and there may be difficulties in comparing values for the same NPU code.

If the unit is an International Unit (IU), an international certified reference material (e.g. WHO reference material) is specified in the specification to the kind-of-property.

If there exist no an international certified reference material, the laboratory can specify the unit at the placeholder, procedure defined unit.


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.


Laboratory field


Thrombosis and Haemostasis

Generic abbreviated form NNPU28115 B—Fibrinogen; arb.massc.(thrombelastography; proc.) = ?
Full form with a result NPU28115 Blood—Fibrinogen; arbitrary mass concentration(thrombelastography; procedure) = 154 arbitrary unit
Abbreviated form with a result NPU28115 B—Fibrinogen; arb.massc.(thrombelastography; proc.) = 154 arbitrary unit
Written expression The arbitrary mass concentration of fibrinogen in Mr Smith’s blood is [154] arbitrary unit. The measurement is performed according to a thrombelastography procedure defined by the given laboratory.

“Arbitrary unit/L” was chosen by a local laboratory as a proprietary measurement unit and not an accepted international unit.


NPU database, and
  • Kind-of-property

    • Nominal kind-of-property

    • Kind-of-quantity

      • Unitary kind-of-quantity

        • Arbitrary 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
2010-05-21 Arbitrary mass concentration Term established.