Distribution width - Dynamic NPU Manual

Distribution width

Definition in words

Unspecific volume of component B in system 1

Note: Distrution width refers to statistical parameters of volume, e.g. coefficient variation or standard deviation of volume of a given component B (e.g. coefficient variation of erythrocyte volume)

Systematic terms

Distribution width 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-∞

Unit

fL, pL, nL, µL, mL, L

Special rule(s) in the NPU syntax

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

“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.

Reference

  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. Doi:10.1039/9781782622451.
  2. IUPAC Goldbook homepage. http://goldbook.iupac.org
  3. Lehmann HP, Fuentes-Arderiu X, Bertello L. Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996). Pure and Applied Chemistry. 2009;68(4):957-1000. doi:10.1351/pac199668040957.

Laboratory field

Examples

Clinical Chemistry

Example 1
Generic abbreviated form NPU18601 Ercs(B)—Erythrocyte volumes; distribution width(procedure) = ? fL
Full form with a result NPU18601 Erythrocytes(Blood)—Erythrocyte volumes; distribution width(procedure) = 40 femtolitre
Abbreviated form with a result NPU18601 Ercs(B)—Erythrocyte volumes; distribution width(procedure) = 40 fL
Written expression The distribution width of erythrocyte volumes of the erythrocytes in Mr. Smith’s blood is [40] fL. The measurement is performed according to a procedure defined by the laboratory,
Example 2
Generic abbreviated form NPU53986 Trcs(B)—Thrombocyte volumes; distribution width(proc.) = ? fL
Full form with a result NPU53986 Thrombocytes(Blood)—Thrombocyte volumes; distribution width(procedure) = 14 femtolitre
Abbreviated form with a result NPU53986 Trcs(B)—Thrombocyte volumes; distribution width(proc.) = 14 fL
Written expression The distribution width of thrombocyte volumes of the thrombocytes in the Mr. Smith’s blood is [14] fL. The measurement is performed according to a procedure defined by the laboratory,

Reference

NPU database, https://www.ifcc.org/ifcc-scientific-division/sd-committees/c-npu/npusearch/ and http://www.labterm.dk/default.aspx
  • Kind-of-property

    • Nominal kind-of-property

    • Kind-of-quantity

      • Unitary kind-of-quantity

        • Rational unitary kind-of-quantity

          • Distribution width

Reference

  • 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 of entry Term Note
1996-01-01 Distribution width The term is established
Date of entry Note Example
2018-12-10

There is no unique definition of distribution width. The definition is dependent on the used measurement procedure that varies between laboratory vendors.

(Lippi G, Pavesi F, Bardi M, Pipitone S. Lack of harmonization of red blood cell distribution width (RDW). Evaluation of four hematological analyzers. Clin Biochem. 2014;47(12):1100-3.)

 
2019-03-18

Width is a non-recommended term for the kind-of-quantity, breadth, a subconcept to length. However, as shown, distribution width is a volume kind-of-quantity, not a length kind-of-quantity. See page 92 in below reference.

(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.