Project Details Establishing definitions for non-referenced terms in the NPU terminology

Project No.: 
Start Date: 
01 August 2010
End Date: 


Establishing definitions for about 3000 non-referenced terms in the NPU terminology.


The NPU terminology is a coding system intended for communication, storage and presentation of laboratory data in health care records and other electronic media in the field of health care.
Descriptions of result items (‘patient properties’) in the NPU terminology are structured by placing terms for basic scientific concepts in a specific syntax. For instance does the NPU description of “concentration of acetone in patient urine expressed in g/l” look like this:

NPU27945 Urine—Acetone; mass concentration = ? gram per litre


Each ‘word’ in this description has a reference (placed in parenthesis below) to an external source that specifies both the correct scientific term and its meaning.

Urine (MSH D014556) – is defined in Medical Subject Headings

Acetone (CAS 67-64-1) – is defined in Chemical Abstract Services

mass concentration (IUPAC)– is defined by IUPAC (‘Green Book’)

gram per litre (BIPM) – is defined in the SI metric system


These references enable secure translation of the NPU code descriptions – as the semantic content of each ‘word’ is internationally known via its reference.

Most of the basic terms and concepts are defined by references to other terminologies, but about 3000 basic concepts have no formal reference or definition. They may have been included in the terminology before a reliable external source came into being. More often they are everyday words that do not belong to any scientific vocabulary, but are used with a specific meaning in the NPU context. To enable secure translation of NPU terminology, the meaning of these terms and concepts as used in the NPU context should be clear.


  • The undefined expression ‘37 °C’ is used in NPU definitions, where it indicates ‘estimated assuming a system temperature of 37 °C’.
  • The undefined expression ‘II’ in NPU definitions indicates ‘oxidation state II (of a chemical element)’. This should be described to avoid its use in e.g. coagulation factor numbering.
  • The undefined expression ‘solute’ is actually defined in the IUPAC Orange Book p. 83 and should have a terminological reference to IUPAC.


The project aims at reducing the number of undefined terms by

  1. finding external terminology references
  2. creating formal definitions
  3. if neither is possible, filing descriptions/examples of the meaning and use of the terms for future use in the local NPU context

This will support managers of the terminology in precise and consistent use of these concepts, and will be an aid in translation of the terminology into other languages.


Visit the related website

May 2017 update – The working group has reviewed all the 3000 terms and following the work on qualifying the terms has been a process for many discussions – and is the reason for the delay in finalizing the project. A Guideline for the managers of the NPU Terminology is ready in the first draft version and will be discussed in the forthcoming meeting in the C-SC-NPU in June 2017. The project is planned to be finalized in the end of 2017.

Page last updated 30 May 2017