What is Proficiency testing?

Proficiency testing determines the performance of individual laboratories for specific tests or measurements and is used to monitor laboratories’ continuing performance. Proficiency testing is also called interlaboratory comparison. As this term implies, Proficiency testing compares the measuring results obtained by the participating laboratories.


Why should I participate in Proficiency testing?

Participation in WEPAL-QUASIMEME Proficiency tests allows your laboratory to compare your performance to those of other, similar laboratories. Proficiency testing is an essential element of laboratory quality assurance. The presence of systematic errors and/or random errors will be revealed, which allows your laboratory to take - if it feels necessary - corrective actions to improve the performance. Each laboratory gets a performance score (z’-score) for each reported test result. This score will prove the laboratory's good performance. Proof which can be used to convince your staff, your clients and your National Accreditation Body.


Do I need Proficiency testing?

Yes, if your laboratory wants to comply with international standards (ISO) and (inter)national legislation regular participation in Proficiency testing is mandatory. Proficiency tests are a basis for the integrity and trust of the customer, accreditation body, and management. Regular participation to Proficiency tests is prescribed in the ISO17025. National accreditation bodies (NAB) will audit whether your laboratory participates in relevant schemes and how the evaluation of the results is implemented in your quality system.

What are my benefits of routine Proficiency testing?

  • Validate internal laboratory Quality Assurance.
  • Beneficial for method development and improvement.
  • Support accreditation (e.g. ISO17025).
  • Support QA of environmental monitoring data.
  • Provide data for national or international programmes.

Perhaps as importantly for the technical performance of the laboratory, regular Proficiency testing provides independent feedback on the quality of analytical results, enabling your laboratory to monitor and improve performance over time.


Why should I choose for WEPAL-QUASIMEME?

  • WEPAL-QUASIMEME has over 65 (!) years of experience in Proficiency testing.
  • Participation is open to all laboratories involved in the offered matrices. Within WEPAL-QUASIMEME, WEPAL covers the Proficiency tests related to the terrestrial environment (soil, plants, manure, compost and biomass) and freshwater sediment. QUASIMEME covers the Proficiency tests organised in the marine environment (seawater, marine sediment, biota and shellfish toxines)
  • The vast number of determinands to choose from range from elements, chemical pollutants, toxins, and nutritional values to microplastics and human and animal pathogens.
  • WEPAL-QUASIMEME Proficiency tests are recognised by the National Accreditation Bodies. The organisation is compliant to ISO17043 and accredited by the Dutch Accreditation Council RvA.
  • All received samples are guaranteed homogeneous and stable for the objective of the test.
  • Track trace information of shipped packages is available.
  • WEPAL-QUASIMEME offers competitive fees.
  • Participants in WEPAL-QUASIMEME programmes are entitled to discounts for multiple orders e.g. Proficiency testing programmes, available reference materials and other services.
  • Determinands can be added to a program free of charge when possible.
  • Reports are strictly confidential and published within four weeks after the submission deadline.
  • With regular questionnaires WEPAL-QUASIMEME investigates your needs to improve the quality of the services provided.

How does my participation work?

In WEPAL-QUASIMEME Proficiency tests the participating laboratories receive at least two samples per program/period. Each laboratory analyses the samples according to the method used in their normal routine and reports its results to WEPAL-QUASIMEME. The analytical results reported by each laboratory are compared to the reference value for that measurand. The reference value (consensus value) for WEPAL-QUASIMEME is determined using robust statistics.

What is the added value of my participation?

After receiving a Proficiency test report, the scores can be assessed on performance. In the event of poor performance, you are able to take corrective measures to properly guarantee the quality of your laboratory. Internally, the obtained Proficiency test material and/or the results of the Proficiency test can also be used for other daily quality assurance purposes, such as specific validations or harmonization of new analysis methods or sampling techniques. An example of this is the determination of the precision and correctness in varying matrices and parameters.

How do I subscribe to a WEPAL-QUASIMEME interlaboratory study?

  • Fill in the application form here
  • Select the programmes and rounds you wish to subscribe to.
  • It is strongly advised to join each round organised for a selected exercise in a specific year. Nevertheless, it is also possible to join a single round or a selection of different rounds.
  • When your laboratory needs a proforma invoice first, you can request a quotation in the application process.

What are the rules for testing a Proficiency test sample?

A PT sample should be treated and tested exactly like any other sample that is tested by the participating laboratory, which is a requirement from ISO17025 and ISO17043. It should not receive any special treatment or attention. Excessive testing is not allowed. Only when the laboratory performs a test in duplicate routinely, the PT sample may also be tested in duplicate. No extra QC, nor extra calibration may be done that is deviating from the routine procedure that is used for regular samples to be tested. Also it is not allowed to contact other participating laboratories about the test results on the PT sample before the final PT report is published.


Can I report my results electronically?

Yes. Subscribe to one of the WEPAL-QUASIMEME Proficiency tests gives you admittance to the members website. Here you can submit your analytical data. Your data are stored directly in the WEPAL-QUASIMEME database, including a data check. Adding and changing the data is possible until the deadline of the current period.

How is my confidentiality guaranteed?

  • WEPAL-QUASIMEME is designed to support the quality systems of laboratories. The information provided can be used by the laboratory for accreditation and for submission of data to monitoring, research or contracted organizations. It is the full responsibility of the laboratory to disclose information on its participation in WEPAL-QUASIMEME and its performance.
  • While WEPAL-QUASIMEME gives full support to each laboratory's quality system, it is not in itself part of that system. In setting this standard of confidentiality WEPAL-QUASIMEME maintains a position of impartiality. Support can be given to a laboratory which may requests assistance to improve performance in a particular study, for instance using the network to enable a participant to contact an experienced laboratory who can provide guidance and specific information. The laboratory itself  decides when, if and to whom it makes information on its methods and performance available.
  • The following statements refer to data and information.
  1. WEPAL-QUASIMEME complies with the European General Data Protection Regulation (Directive 95/46/EC).  
  2. All reports and information on the performance of individual participants will remain confidential within the WEPAL-QUASIMEME team. WEPAL-QUASIMEME will not convey any information on data generated by a specific participant in the laboratory performance study to any third party without permission of the participant. This also includes the transfer of information from one participant to another within the proficiency testing studies
  3. All individual sets of data generated by a participant in the WEPAL-QUASIMEME studies including information on the assessment of performance of the laboratory such as Z-scores or comments on laboratory performance shall remain the property of the laboratory submitting these data.
  4. WEPAL-QUASIMEME is allowed to use data of laboratories for studies and publications when the data are made anonymous and cannot be traced back to the laboratory. Examples of such studies include papers on statistics or evaluations of performance criteria.
  5. Participants may use data and information extracted from WEPAL-QUASIMEME reports after written permission from WEPAL-QUASIMEME with due acknowledgement to WEPAL-QUASIMEME.
  6. All general comments made by the WEPAL-QUASIMEME assessors on any study, where there is no specific reference to any identifiable laboratory, shall remain the property of WEPAL-QUASIMEME and be available for publication.
  7. WEPAL-QUASIMEME strongly recommends each participant to make full use of their own study performance results in support of their Quality System for chemical measurements.

    What are the deadlines for submission of results?

    Each round runs for approximately three months (January-March, April-June, July-September and October-December). Participants can send in results during the entire period of each round. Deadlines for each round are presented in the table below.

    Programme Round 1 Round 2 Round 3 Round 4
    Soil (ISE) 31 March 30 June 30 September 31 December
    Plants (IPE) 31 March 30 June 30 September 31 December
    Freshwater sediment (SETOC) 31 March 30 June 30 September 31 December
    Marine sediment (MS) 30 June 31 January
    Seawater (AQ) 30 June 31 January
    Biota (BT) 30 June 31 January
    Shellfish toxins (BT) 30 June 31 January
    Manure & Compost (MARSEP) 31 March 30 June 30 September 31 December
    Biomass (BIMEP) - 30 June - 31 December

    Can I purchase extra sample(s)?

    Yes. If you participate for many determinands, it is possible the supplied amount of material is less than needed, in that case you can ask for additional samples against a reduced price.

    Can I purchase reference materials?

    Yes. Samples from the Proficiency test schemes are available as reference material, which can be used for method development or as reference samples for internal quality control. The reference materials are delivered with a certificate of analysis or a summary of the statistics.

    For more information see Reference materials

    Which additional services does WEPAL-QUASIMEME offer?

    • Option for ordering reference samples used in our regular proficiency testing scheme.
    • Preparation of internal reference materials from material collected and offered by your own laboratory, with or without consensus values.
    • Organisation of proficiency tests for a selected group of laboratories.
    • Organisation of proficiency tests within your laboratory, to compare results from several colleagues.
    • Organisation of development exercises on new emerging pollutants or difficult compounds to analyse.
    • On behalf of the International Organization for Standardization (ISO) WEPAL-QUASIMEME also organises international laboratory-evaluating programmes for environmental and agricultural laboratories.

    For more information see tailored services