Given the requirement of customers, over the years clinical laboratories began to develop a continuous improvement of processes, thus improving the quality of the product offered, or exams for their clients or patients. With the evolution in the clinical set up internal controls, which comes with its reference results provided by the manufacturer, to measure the reliability of the equipment daily. And the external control that comes without results, serving to compare with results from other laboratories. Through these concepts the study was conducted in a laboratory of outsourced clinical analysis of a public hospital in São Paulo, who spends every year by the audit that analyzes and evaluates the causes of deficiencies. The study used daily data controls in biochemical equipment routine Cobas c 311, within one month totaling 58 analytes. It was noted considerable heterogeneity in the values obtained, the vast majority of the results were outside the average, with both low values as above average, but the same were within the reference values, so were accepted in the routine laboratory. The solution to certain problems it is up to the challenge managers to broaden their knowledge, engage and trained team of employees, so the quality can be improved to reduce costs and increase laboratory productivity.