Only laboratories that have the personnel and equipment required for the EQAT proficiency test phytoplankton can participate in our scheme. Laboratories that subcontract our services to third parties are not entitled to participate in the proficiency test. When registering, each participating laboratory must name a member of staff who has been commissioned to carry out the analyses. The certificate is issued for this employee. If this condition is violated, the participant is not entitled to the certificate. Each participant in the EQAT scheme requires its own registration/application.
The participation fee for all participants is currently € 1,070.00 plus 19% VAT (DE). After registration via the web portal www.planktonforum.eu, invoices (in pdf format) will be sent by e-mail. The e-mail address must be given at the time of registration. Participants from within the EU but outside Germany will receive a net invoice if they provide their VAT ID. Payment of the participation fee is only possible by bank transfer. Any bank charges incurred are not included in the participation fee and are to be borne by the participant. Payments must be received on our EQAT account by the respective specified date. Registered participants who have not made full payment by this date will be excluded from participation.
A later payment is not possible, because at this time the production of the reference counting chamber and the natural sample will be started. There will be no refund of fees already paid in case of non-participation.
The fees include the following services:
Production of the reference counting chamber
Sampling from natural waters and/or selection of suitable test materials from algal strain collections and their cultivation
Preparation of the natural samples
Homogeneity tests (according to DIN ISO 13528:2020)
Stability tests during the duration of the inter-laboratory comparison (according to DIN ISO 13528:2020)
Production of the video clips, sampling, selection of suitable species
Taxonomic reconciliation including assurance from specialists
Packaging and shipping of the samples
Provision of the video clips as download from our website
Provision of online forms/software tool for entering the results
Evaluation of the results according to DIN 38402 – 45:2024 / DIN ISO 13528:2020
Preparation of participation certificates and result sheets
Final report as download
The evaluation of the data gathered in component 1 and 2 is based on robust statistical procedures using zu scores according to DIN 38402–45:2014 and DIN ISO 13528:2020, respectively. Before application of the robust statistics, the data are scanned for very large outliers. When present, we only exclude results with a deviation from the robust mean value of more than 104 from further evaluation. The remaining results are used to determine the assigned target values and the comparative standard deviations. As a method of robust statistics the estimation method according to HAMPEL and the Q method (calculation of the repeatability and comparative standard deviation) are used. These parameters are calculated software-supported with the AQS Excel macro for proficiency testing evaluation by M. Koch, University of Stuttgart. The HAMPEL estimator is defined as the assigned target value. The comparative standard deviation calculated using the Q method is defined as the target standard deviation for the corresponding criterion. The combination of both methods guarantees an efficient and robust determination of conventionally correct values.
The z-scores are calculated using the following formula:
z = (y-û) / sSoll (Formula 14 in DIN ISO 13528:2020),
where y is the laboratory mean, û is the assigned target value (HAMPEL estimator) and ssoll is the target standard deviation. In our evaluation, we use the zu score, which is calculated from the z score, taking into account an asymmetric tolerance interval (Uhlig & Henschel, Fresenius J Anal Chem (1997) 358: 761-766). The z-scores are converted into zu-scores using an iteratively determined factor in order to take the symmetry of the tolerance interval into account. To pass a certain task a zu-score < |2| has to be reached. The results are listed for every participant on result sheets. To be successful for participation in a certain task, the quality target as specified on the certificate has to be reached. This quality target is normally set at establishing a 2/3 majority of zu-scores < |2|.
The evaluation of the taxonomic results of component 3 is done qualitatively. In this case, the evaluation is based on the LAWA-AQS data sheet A3 (LAWA-AQS data sheet A3 ), which requires a success rate of at least 80% for all parameters. If the determination is correct up to the required determination level, 1 full point is awarded. If the determination is not correct, further points are awarded proportionally according to the correct determination of the next lower taxonomic categories, see table below.
Evaluation scheme for component 3 (taxonomy)
Points |
Qualification |
1 |
Species or genus correct |
0.7 |
Species required, genus correct. Species not specified („sp.“) |
0.67 |
Species required, genus correct. Species wrong |
0.5 |
Genus required, but wrong. Next taxonomic level correct |
0.33 |
Species required, species and genus wrong. Next taxonomic level correct |
0 |
Next taxonomic level wrong (or not provided) |