Investigating poor performance in proficiency testing


Factors affecting PT strategyA laboratory will occasionally have a poor performance in a PT scheme. When this occurs, the laboratory should acknowledge it, carry out an investigation and document a review of possible causes, even if it decides not to take any specific action. This leaflet, prepared by the EURACHEM Proficiency Testing Working Group, gives advice for laboratories on how to best address such events.

This second edition is an editorial amendment to reference recent guidance on proficiency testing.


The second edition is currently available in the following languages. Links to translations of the first edition, available in 10 languages, are temporarily maintained on this page (below) for convenience while translations of the second edition are prepared. 


Please consult the PT Working Group Chair if you would like to prepare a translation in your own language.

Previous editions

The first edition of this information leaflet can be found here, in our publication archive. Selected translations of the first edition are listed below for convenience pending translation of the second edition.



1. Dates show date of publication of the linked file on this website.

2. 2nd English edition first published 2022-07-30