The origin of the EQAT inter-laboratory test

The EQAT scheme has its origin in the quality management activities of the biology workgroup of the Arbeitsgemeinschaft Trinkwassertalsperren (ATT e.V.) in the 1990s. Since 2002, the proficiency test phytoplankton has been carried out on an international level by the LTV.

The analysis phase has begun.

We are happy to have 65 participants from 16 different countries for the EQAT proficiency test phytoplankton 2023.

The analysis period is extended and runs from 04.04.2023 - 14.7.2023.
Please start with the processing of the natural sample and the determination of the video clips.
The submission of results is only possible via the web portal. Please contact us immediately if any problems arise in the process.
News regarding the reference counting chamber. Delivery to the EQAT lab is now announced for week 19 (8-12.5.). We are therefore aiming to deliver them to you by the end of May.

After completion of this phase, results can no longer be submitted.

Proficiency test phytoplankton 2023

Why to take part in a proficiency tests and why participating in our EQAT scheme?

Inter-laboratory comparisons are an essential part of external quality assurance. Laboratories can test and improve their analytical performance. The EU Water Framework Directive sets high standards for the quality of phytoplankton analysis and requires regular participation in proficiency testing. EQAT Phytoplankton organises such ring trials every 2 years. The German Accreditation Body, DAkkS (, accredits EQAT Phytoplankton for phytoplankton analysis according to DIN EN ISO 17025:2018 and as a provider of interlaboratory comparisons according to DIN EN ISO/IEC 17043:2010. With the help of the innovative reference counting chamber developed by EQAT Phytoplankton, systematic errors can be clearly distinguished from errors related to the detection of algae. This is done within the established work processes at the inverted microscope (Utermöhl technique).

The proficiency tests are based on the procedures described in the DIN EN 15204:2006 Guidance standard on the enumeration of phytoplankton using inverted microscopy (Utermöhl technique) and in DIN EN 16695:2015 Water quality - Guidance on the estimation of phytoplankton biovolume.

Design of our EQAT scheme

The EQAT design is focused on the application of the Utermöhl method using the inverted microscope and consists of three components. Components 1 and 2 are methodological, focussing on the enumeration and biovolume calculation and component 3 is taxonomic in nature.

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Procedure of our EQAT scheme

The EQAT scheme is divided into 9 phases, the status of which can be viewed on-line on our website. With the announcement of the EQAT scheme, the planned time schedule is communicated to the participants.

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Requirements for participation, costs and evaluation

Only laboratories that have the personnel and equipment required for the EQAT proficiency test phytoplankton can participate in our scheme. Each participant in the EQAT scheme requires an individual registration.

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About the organiser

The EQAT phytoplankton proficiency tests are an activity of the Landestalsperrenverwaltung des Freistaates Sachsen (LTV). 

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Since 2005, the evaluation of the results has been carried out in accordance with DIN 38402 – 45: 2014 using robust statistical methods.

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Show your colleagues and clients that you participate in the EQAT proficiency test phytoplankton!

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