Abstract
Confidence in the quality of products, which were produced by the enterprise, is the key of success and competitiveness in the market. Confirming products’ quality and environmental security of the manufacture is impossible without a well-functioning testing and calibration laboratories, which can provide the accuracy of their results.Now, external evaluation of the laboratories’ competence by proficiency testing is one of the main instruments of development of laboratories’ activities and improving the quality of researches. Even with a perfectly functioning management system, high-precision expensive equipment and professional operators, without external evaluation laboratories can work for a long period with an offsets or significant random variations in measurement results. Only through proficiency testing, laboratories can reveal the presence of this kind of problem. Participation in Interlaboratory comparisons makes it possible to identify the "weak" sides of the laboratory operation and the successful implementation of preventive and corrective actions make them more "strong."