Amount-of-substance (am.s.) - Dynamic NPU Manual

Amount-of-substance (am.s.)


Chemical amount


Am.s., substance (subst.)

Definition in words

Number of elementary entities (component B) divided by Avogadro constant in system 1.

Note 1: Avogadro constant is the number of entities in one mole

Note 2: Elementary entity can be an atom, molecule, ion etc.

Definition by equation


Systematic terms

Amount-of-substance of component B in system 1

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)


fmol, pmol, nmol, μmol, mmol, mol


  1. IUPAC Goldbook homepage.
  2. SI brochure “Unit of amount of substance (mole)” (Avogadro constant)
  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.
  4. 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
NPU17540 U—Creatininium; am.s.(proc.) = ? mmol
Full result NPU17540 Urine—Creatininium; amount-of-substance(procedure) = 12 millimol
Abbreviated result NPU17540 U—Creatininium; am.s.(proc.) = 12 mmol
Written expression The amount-of-substance of Creatininium in Mr. Smith’s urine is [12] mmol.The measurement is performed according to a procedure defined by the laboratory,

Clinical Phamarcology

Example 2
Generic abbreviated
NPU08619 U—Dopamine; am.s.(proc.)=  ? µmol
Full result NPU08619 Urine—Dopamine; amount-of-substance(procedure)=  10 micromol
Abbreviated result NPU08619 U—Dopamine; am.s.(proc.)=  10 µmol
Written expression The amount-of-substance of Dopamine in Mr. Smith’s blood is [10] µmol. The measurement is performed according to a procedure defined by the laboratory,

Thrombosis and Haemostasis

Example 3
Generic abbreviated
NPU08951 Trcs(B)—ATP release, collagen induced; am.s.(proc.) = ? nmol
Full result NPU08951 Thrombocytes(Blood)—ATP release, collagen induced; amount-of-substance(procedure) = 0.5 nanomol
Abbreviated result NPU08951 Trcs(B)—ATP release, collagen induced; am.s.(proc.) = 0.5 nmol
Written expression The amount-of-substance of collagen induced ATP release from thrombocytes in Mr. Smith’s blood is [0.5] nmol.The measurement is performed according to a procedure defined by the laboratory,


NPU database, and


  • Kind-of-property

    • Nominal kind-of-property

    • Kind-of-quantity

      • Ordinal kind-of-quantity

      • Unitary kind-of-quantity

        • Rational unitary kind-of-quantity

          • Amount-of-substance


  • 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 Reference
1996-01-01 Amount-of-substance Term established NPU database, and