IMPORTANCE OF PROFICIENCY TESTING PROGRAMMES FOR THE CORRECTNESS OF LABORATORY RESULTS

The proficiency testing (PT) is one of the best ways for an analytical laboratory to carry out its external quality control, to monitor its performance regarding both its own requirements and the norm of other laboratories at national and international levels. PT helps to highlight not only repeatability and reproducibility performance among laboratories, but also systematic errors. Laboratories should select PT which operates in accordance with good international practice and has transparent evidence of quality e.g. by accreditation. The National Reference Laboratory (as a part of Central Institute for Supervising and Testing in Agriculture) provides the PT for analytical laboratories for soil, plant, feedstuff, sludge and sediment analyses and also further special programmes (the analysis of oil plants, the determination of additives in feedstuffs, the determination of mycotoxins in feedstuffs and food, the qualitative detection of the viral infection in plants, the qualitative detection of animal proteins in feedstuffs). Tailor-made software for all actions connected with PT (statistical evaluation, results transfer, sample database, stability evaluation, long term evaluation of the results for a particular parameter(s), list of participant(s) and method indicating codes, etc.) is used. All procedures of the statistical evaluation of the PT MPZ UKZUZ results are robust so that the influence of outliers is excluded. The report is immediately distributed to the participants by the E-mail.