Time - Dynamic NPU Manual



Duration, time elapsed, age, life expectancy, time difference

Definition in words

A specific moment of time minus another specific moment of time

Note 1: Time is a SI base kind-of-quantity

Note 2: Component B may be a chemical, biological or physiological proces, e.g. coagulation

Definition by equation

Systematic terms

Time 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-∞


s (second is the corresponding base measurement unit), h, d (day or 24 hours), m (month), year(s) etc.

Non-recommended term

Period of time


  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. BIPM homepage. https://www.bipm.org/en/bipm/tai/
  4. 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


Molecular biology and Genetics


Example 1
Generic abbreviated
NPU18233 Pt—Age; time = ? Year(s)
Full result NPU18233 Patient—Age; time = 33 Year(s)
Abbreviated result NPU18233 Pt—Age; time = 33 Year(s)
Written expression The time of Mrs. Smith’s age is [33] years.

Reproduction and Fertility


Example 2
Generic abbreviated
NPU01528 Pt—Duration to next expected menstrual period; time = ? d
Full result NPU01528 Patient—Duration to next expected menstrual period; time = 10 day
Abbreviated result NPU01528 Pt—Duration to next expected menstrual period; time = 10 d
Written expression The time of Mrs. Smith’s Duration to next expected menstrual period is [10] days.

Thrombosis and Haemostasis

Example 3
Generic abbreviated
NPU01682 P—Coagulation, surface-induced; time(proc.) = ? s
Full result NPU01682 Plasma—Coagulation, surface-induced; time(procedure) = 34 second
Abbreviated result NPU01682 P—Coagulation, surface-induced; time(proc.) = 34 s
Written expression The time of surface-induced Coagulation in Mr. Smith’s plasma is [34] s.


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

        • Differential 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
1996-01-01 Time Term established
Date Notes


2019-09-06 Time may also mean a specific moment of time, e.g. 16th April 2016 at 14:30:30. However, this definition is not used in the NPU terminology.
2019-09-06 Other kinds-of-quantity with the same definition exist. Such as durationlife spantime interval.