EU Science Hub

Current practices and future directions of proficiency testing in analytical chemistry

Proficiency testing in analytical chemistry
Jun 17 2019

The JRC contributed as expert proficiency test (PT) provider to discussions related to current practices and future directions on external quality assessment (EQA).

As shown by the JRC since 20 years already, the reporting of results together with their uncertainties by PT participants and subsequent evaluation by the PT/EQA provider are the most effective measures to demonstrate good laboratory performance.

A proficiency test (PT) is an interlaboratory comparison aimed to assess the performance of individual laboratories for specific tests or measurements. During a PT one or more samples are sent to several participating laboratories. Each laboratory analyses the samples and reports its measurement results to the PT coordinator. The reported results are then evaluated and each laboratory receives a performance rating.

Achieving regularly successful PT assessments is a prerequisite for a laboratory to obtain accreditation according to ISO/IEC 17025 and to act as official control laboratory in the EU, for instance in food/feed or environmental controls.

The Proficiency Testing Working Group of Eurachem organised a workshop on PTs in analytical chemistry, microbiology and laboratory medicine in Portoroz, Slovenia, from the 9–12 October 2017. JRC experts contributed to the preparation and execution of this workshop which was attended by 200 participants from 53 different countries.

Proficiency testing for the determination of the mass fraction of oligomers in food simulant

©EC, 2018

The following topics were covered by the working group discussions:


- the importance of interpretive PT schemes;
- changes to PTs in developing countries over the last 10 years;
- traditional versus virtual PT items;
- implementation of ISO/IEC 17043 for sampling PTs;
- experience of the implementation of a guidance from European Accreditation (EA) on PT participation;
- use and treatment of measurement uncertainty in PT schemes.

During discussions of the last topic it appeared that: (i) an increasing number of PT providers ask routinely participants to report their measurement uncertainty; (ii) some participants insist on reporting their measurement uncertainty even when they are not requested to; while (iii) many of the reported measurement uncertainties seem to be overestimated or set to the maximum uncertainties allowed by legislation.

Read more in:
B. Brookman et al. "Proficiency testing in analytical chemistry, microbiology and laboratory medicine: discussions on current practice and future directions", Accred. Qual. Assur. 24 (2019) 93-101 

DOI: 10.1007/s00769-018-1343-7