FAQ

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.

WEPAL-QUASIMEME is an organiser for proficiency tests in environmental matrices with global participation. WEPAL-QUASIMEME offers proficiency tests related to the terrestrial environment (soil, plants, manure, compost and biomass), the freshwater environment (freshwater, wastewater and sediment), the marine environment (seawater, marine sediment, biota and shellfish toxins).

WEPAL-QUASIMEME is more than a proficiency testing scheme. The routine laboratory performance studies of WEPAL-QUASIMEME provide the basis of external quality assurance for institutes that make regular chemical measurements in the terrestrial, aquatic and marine enviroment. Most studies have two or four rounds per annum with per round a minimum of two test materials containing the analytes at different concentrations.

WEPAL-QUASIMEME offers worldwide accredited proficiency testing programmes (ISO17043) and samples from the proficiency test schemes are available as reference material in our webshop.

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.

• 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.

• 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.

• WEPAL-QUASIMEME has over 65 (!) years of experience in Proficiency testing.
• Participation is open to all laboratories involved in the offered matrices.
• 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.

• Natural test materials of relevant matrices with determinands at realistic concentrations.
• Test materials with full evidence of homogeneity and stability for the duration of the test.
• Clear protocols how to handle the test materials.
• Full performance assessment based on robust statistics, performance summary sheets and exercise reports.
• Confidential information on own laboratory performance and anonymised results from all participants.
• Method information about the methods used by participants.
• Workshops for discussion and improvement in methodology.
• A Helpdesk, which is supported by experts in the field.
• News, workshops and conferences.

• 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.

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.

• 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.

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.

When participating in a WEPAL-QUASIMEME proficiency test programme, you may receive three types of reports during the annual cycle.

1. The individual evaluating report of your performance (Z-scores) in a round of a proficiency test programme presented as .pdf and as .csv file, that can be imported directly into your quality system
2. A periodic report with the testing results of all participating laboratories in a certain round
3. An annual report summarizing the overall testing results of the proficiency test programmes from WEPAL on soil, plant, freshwater sediment, biomass and manure & compost.

The results of your determinations are processed at WEPAL-QUASIMEME and published under confidential code names.

Content

The WEPAL-QUASIMEME reports contain:

• all individual data with information about the method used (MIC)
• a statistical evaluation
• for QUASIMEME a table with ranked performance
• a summary of the results for each sample
• z'-score plots based on consensus values per determinand/matrix combination using robust statistics showing the deviation from the reference value (see graph).
• other graphical information (ranked results and histograms)

Click here to get a glimpse of what to expect in a report.

Method Indicating Code (MIC)

WEPAL-QUASIMEME provides all reported results with a Method Indicating Code (MIC). The code indicates the critical steps in the procedure of analysis that can affect the results. This offers all participants the possibility to compare the results of their analytical procedures more specifically with the results of other participants.

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. These documents are based on results from the WEPAL-QUASIMEME PT schemes. The certificates provide information about:

• the consensus value: the mean value of the dataset obtained from the PT, calculated with robust statistics
• the standard deviation and coefficient of variation
• number of results used to calculate the consensus value
• median and MAD (Median of Absolute Deviation)

An overview of the reference materials and more information about how to order can be found in the WEPAL-QUASIMEME webshop.

• 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