Project Details Internationally agreed terminology for observations in scientific communication

Project No.:
Start Date:
01 September 2004
End Date:
04 May 2018
Division Name:
Chemistry and Human Health Division
Division No.:


Most scientific disciplines, not only laboratory medicine, rely to some extent on observations in addition to measurable quantities. An integrated explanatory treatise and vocabulary explaining and exploring the conceptual relationship between observations and measurements is the main outcome of this project.

The C-NPU subcommittee, maintained as a joint IFCC-IUPAC activity for two decades, has as its main task to promote and maintain scientifically and conceptually sound ways of expressing the outcome of measurements and other examinations in laboratory medicine. The NPU coding scheme and vocabulary, based on the SI system, concepts theory and high-level international standards should be the cornerstone for expressing measurements within international communication standards. The proposed project should be used to explain and extend the systematic description of properties to observable properties.

>> access C-NPU via the Subcommittee homepage


Scientists of disciplines in laboratory medicine has long recognized the need of a common language for efficient and safe request of investigations, report of results, and communication of experience and scientific achievements. To achieve this the IFCC and the IUPAC in a joint project have developed a metrologically based coding scheme based on progress in modern classification science. In collaboration with professionals in a series of medical specialties a coding scheme has evolved that fulfils the needs in electronic communication and data presentation. The C-NPU coding scheme provides a global standardized classification and coding scheme for properties examined in laboratory medicine based on kind-of-property, component and system and is basic if a coherent system with global acceptance is to be worked out. The C-NPU generic database is published under the URL: <>.

Such a coding scheme needs to deal with properties that are observed in the medical laboratory that are not defined by the seven dimensions of the SI system for measuring quantities with its primitive concepts defined in the VIM (International Vocabulary of Basic and General Terms in Metrology). The vocabulary VIM is designed for metrology: science of measurement. However, most scientific disciplines, not only laboratory medicine, rely also, some predominantly, on observation and it could be commendable to design a vocabulary shared by both observations and measurements.

Typical cases are several technical reports in PAC authored by the C-NPU that relies heavily on observable properties such as “taxon” because of the nature of the observed properties in for example clinical microbiology or molecular biology.

The present project is aimed at developing a common framework for a project meant to integrate and also explain to the laboratory medicine workers the meaning of and usefulness of such an integrated view of the concepts property and in a more restricted sense quantity.


> project announcement published in Chem. Int. Nov-Dec 2004

> Nov 2004 report update (pdf file – 13KB)

> May 2006 report update (pdf file – 14KB)

> June 2007 – A second version of the text has been drafted and distributed for comments within the task group and the sub-committee during our last meeting in early December 2006. Completion anticipated by the end of 2008.

> October 2008 report update (pdf file – 12KB)

> June 2009 – A challenge is to coordinate this project with the Silver Book revision project (project #2007-033-3-700), which is managed in parallel and needs input from this project. The concepts and systematic structure established was completed at the of 2008. A draft text and vocabulary shall be completed early 2010 and distributed for comments among appropriate organizations and individual specialists. A final version, taking into account the comments received, will be submitted for publication in 2010.

A first version of the vocabulary has been published, according to IFCC procedures, in Clinical Chemistry and Laboratory Medicine (Nordin G et al. An outline for a vocabulary of nominal properties and examinations – basic and general concepts and associated terms. Clin Chem Lab Med. 2010 Nov; 48(11):1553-66;

> July 2012 – the provisional recommendations titled “Vocabulary for Nominal Properties and Nominal Examinations – Basic and General Concepts and Associated Terms” was made available for public review until by 30 Nov 2012, further extended to 28 Feb 2013.

In the review process for the publication in Pure and Applied Chemistry some substantial improvements in consistency for the entries have been suggested, and have now been incorporated in the vocabulary. In addition, inspired by suggestions from some of the reviewers, the language has been simplified.

> Dec 2013 update – The PAC recommendation is being finalized and also being approved by IFCC.

> Aug 2015 update – A revised version of the recommendations, after public review, has been submitted for publication in PAC.

> May 2017 update – A version number 10 of the manuscript, hopefully the final version, will be submitted for publication in PAC shorthly.

> May 2018 update – published Nordin, G., Dybkaer, R., Forsum, U., et al. (2018). Vocabulary on nominal property, examination, and related concepts for clinical laboratory sciences (IFCC-IUPAC Recommendations 2017). Pure and Applied Chemistry, 90(5), pp. 913-935;

Page last update 4 May 2018