laboratory proficiency testing - determination of laboratory testing performance by means of interlaboratory test comparisons, proficiency study means analysing the same sample allowing laboratories to choose their own methods, provided these methods are used under routine conditions. The study has to be performed according to ISO guide 43-1 and 43-2 and can be used to assess the reproducibility of methods., labori katsetaseme määramine laboritevaheliste võrdluskatsete abil, méthodes de vérification des performances d'un laboratoire en matičre d'essais, au moyen d'essais interlaboratoires