To assure the quality of service in laboratory medicine, it is necessary to implement a quality system which comprises the entire testing process. The use of quality reagents is an important aspect of the process. Despite the fact that it is the responsibility of the laboratory to ensure the quality of the analytical system (including reagents) and since it is impossible to evaluate all commercial diagnostic kits, the laboratory often depends on statements issued by the manufacturer to select the most appropriate diagnostics for a particular laboratory. In this study we report the results of the analysis of information provided in 887 package inserts enclosed in the more widely used commercial diagnostic kits, following the Standard for the labelling of clinical laboratory materials of the European Committee for Clinical Laboratory Standards (ECCLS). Only a third of these were in agreement with the guidelines of ECCLS Standard, reporting complete and correct information. We believe that it is necessary to implement a constructive cooperation between manufacturers of diagnostic materials and clinical laboratories to produce a more uniform approach to improvements in laboratory quality assurance.