The diagnosis is largely determined by the clinical laboratory conclusion based on a huge number of laboratory indicators and studies. By using a wide range of laboratory methods, the attending physician receives objective information about the patient's health, the dynamics of the disease and the effectiveness of treatment. The research is conducted to study of the performance of the Center for the laboratory tests quality control at the regional territorial-technological level in the Republic of Belarus. The object of the study is the Vitebsk regional control and methodological center for laboratory tests quality control, that is organized at the clinical diagnostic laboratory of the Vitebsk Regional Clinical Cardiology Center. The study is divided into 3 stages. At the first stage the schemes of the Center's work program were mapped based on the investigation by means of literature and documentation analysis and observation of the Center's work. At the second stage the archived data on 2017 and 2019 biochemical tests quality control were statistically processed. The results of 33 clinical diagnostic laboratories control studies on 24 biochemical indicators were analyzed. At the final stage of the study, the role of the regional quality control Center in the republican level of medical laboratories quality control was investigated. Namely, the interaction between the Vitebsk regional control and methodological center for laboratory tests quality control and the Republican Center for Laboratory Diagnostics was studied. The retrospective analysis of the last republican quality control cycle data was carried out. It is concluded that the work of the Сenter is organized in a perspective way, as it corresponds to the modern world trends in the medical laboratories development, meanwhile it is adapted to the local healthcare system as well. It was found that it is impossible to achieve absolutely error-free functioning of any clinical diagnostic laboratory by means of a finite number of quality control cycles carried out in a limited period of time. The advantages and disadvantages of the data statistical processing algorithm used during the republican quality control cycles were revealed as well.