Aim: In this study, we aimed to evaluate the preanalytical process performance by six sigma method and make the necessary arrangements according to the obtained results in our laboratory.

Materials and Methods: The total number of samples, and rejected samples were obtained retrospectively from Hospital Information Management System (HIMS) in Karacabey State Hospital Central Laboratory between January-June 2019 period. Data analyzed according to the reasons, the quality indicator (QI) error rates were determined and sigma values were calculated monthly.

Results: Our laboratory accepted 91559 samples in six months time interval and 1902 of them were rejected. QI error rate was determined as 2,08%. Process sigma level was calculated as 3,6. The pareto analysis revealed that the most common causes of rejection were respectively hemolysed, clotted and insufficient samples.

Conclusion: Most of the errors in the preanalytic phase were determined to be caused by inaccuracies in the blood collection process. Therefore it was planned to provide repeated trainings on preanalytical errors and blood collection for nurses, blood collection unit workers and laboratory technicians. In this way, it was thought that we could serve the desired standards by reducing the errors in the preanalytical process.