Laboratories that are part of clinical centers are faced with the inevitability that their efficiency must be on a high level. Most of the biochemical laboratories are automated, but they are still underperforming. The best approach to increase the efficiency or to improve the processes today is the Lean Six Sigma methodology. This methodology extracts many benefits from automated processes. A lean process in the laboratory focuses on the time cycle to obtain results and reduce costs, or both components at the same time. Six Sigma methodology provides that the processes take place in the laboratory without delays and defects. The process that takes place at the Center for Medical Bio - chemistry (CMB) can be divided into two parts: the first part takes place in the receiving infirmary (pre-analytics) and the second part takes place at the offices of the CMB from the receipt of samples (analytics) to obtained results. The paper observes both processes, identifies critical areas where they come to a halt, defines access and reviews the results obtained using the Lean Six Sigma methodology. By applying Lean tools, the places that do not add value and those that significantly increase the cycle time were identified. This paper presents the results obtained without going into detail about the application of these Lean tools.