Arbitrary fraction ( - Dynamic NPU Manual

Arbitrary fraction (


Definition in words

Fraction of component B in system 1 compared with fraction of component B in a reference system.

Note: The reference system is defined by the laboratory.

Result type

Ordinal scale
  • Value set is ranked accoding to magnitude
  • The value set and the limit of the value set are defined by the laboratory
  • The value set can be either numerical values or words.Example 1Value set={none < some < high < very high}

    Example 2

    Value set={low < normal< high }

    Example 3

    Value set={0 < 1 < 2}

    Example 4

    Value set={negative < positive}

    Example 5

    Value set={+ < ++ < +++}

  • Algebraic operations are not allowed (Ref. 2, 1.26)
  • Possible comparison of values (a<b, a=b or a>b)



Special rule(s) in the NPU syntax

“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.


  1. 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.
  2. Mesures BIdPe. International Vocabulary of Metrology – Basic and General Concepts and Associated Terms VIM 3rd edition JCGM 200:2012 (JCGM 200:2008 with minor corrections). Bureau International des Poids et Mesures; 2008.


Laboratory field


Molecular biology and genetics Generic abbreviated NPU53991 DNA fragment(P)—DNA fragment(Chromosome 13); = ?
Full result NPU53991 DNA fragment(Plasma)—DNA fragment(Chromosome 13); arbitrary fraction(procedure) = Low
Abbreviated result NPU53991 DNA fragment(P)—DNA fragment(Chromosome 13); = Low
Written expression The arbitrary fraction of DNA fragment(Chromosome 13) of all DNA fragment in Mrs. Smith’s plasma is low.

“Low” is a value according to a value set defined by the laboratory.

Fraction of DNA fragment(Chromosome 13) is the quotient of DNA fragment(Chromosome 13) divided by all DNA fragments in Mrs. Smith’s plasma.

Reference NPU database, and
  • Kind-of-property

    • Nominal kind-of-property

    • Kind-of-quantity

      • Ordinal kind-of-quantity

        • Arbitrary fraction

      • Unitary kind-of-quantity


  • 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
2015-06-11 Arbitrary fraction Term established