Entitic mass - Dynamic NPU Manual

Entitic mass

Definition in words

Mass of component B divided by number of entities (component B or system 1) in a system

Alternative: Average mass of component B in a system or mass of component per system 1 in system 2

Definition by equation

Systematic terms

Entitic mass of component B in system 1

Result type

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


pg, ng, µg, etc.

Note: The correct unit is e.g. “pg/1” but “1” is omitted.


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


Clinical Chemistry

Example 1
Generic abbreviated
NPU26879 Rtcs(B)—Haemoglobin; entitic mass = ? pg
Full result NPU26879 Reticulocytes(Blood)—Haemoglobin; entitic mass = 40.4 picogram
Abbreviated result NPU26879 Rtcs(B)—Haemoglobin; entitic mass = 40.4 pg
Written expression The mass of Haemoglobin divided by number of Reticulocytes in Ms. Smith’s Blood is [40.4] pg.

Alternative expresssion:

The mass of Haemoglobin per Reticulocyte in Mrs. Smith’s Blood is [40.4] pg.

Example 2
Generic abbreviated
NPU26880 Ercs(B)—Haemoglobin; entitic mass = ? pg
Full result NPU26880 Erythrocytes(Blood)—Haemoglobin; entitic mass = 28 picogram
Abbreviated result NPU26880 Ercs(B)—Haemoglobin; entitic mass = 28 pg
Written expression The mass of Haemoglobin divided by number of Erythrocytes in Ms. Smith’s Blood is [28] pg.

Alternative expresssion:

The mass of Haemoglobin per Erythrocytes in Mrs. Smith’s Blood is [28] pg.


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

          • Entitic mass


  • 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 Entitic mass Term established