Abstract Background: Quality indicators (QIs) used as performance measurements are an effective tool in accurately estimating quality, identifying problems that may need to be addressed, and monitoring the processes over time. In Laboratory Medicine, QIs should cover all steps of the testing process, as error studies have confirmed that most errors occur in the pre- and post-analytical phase of testing. Aim of the present study is to provide preliminary results on QIs and related performance criteria in the post-analytical phase. Methods: This work was conducted according to a previously described study design based on the voluntary participation of clinical laboratories in the project on QIs of the Working Group “Laboratory Errors and Patient Safety” (WG-LEPS) of the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). Results: Overall, data collected highlighted an improvement or stability in performances over time for all reported indicators thus demonstrating that the use of QIs is effective in the quality improvement strategy. Moreover, QIs data are an important source for defining the state-of-the-art concerning the error rate in the total testing process. The definition of performance specifications based on the state-of-the-art, as suggested by consensus documents, is a valuable benchmark point in evaluating the performance of each laboratory. Conclusions: Laboratory tests play a relevant role in the monitoring and evaluation of the efficacy of patient outcome thus assisting clinicians in decision-making. Laboratory performance evaluation is therefore crucial to providing patients with safe, effective and efficient care.