Process capability estimation for leukocyte filtering process in blood service: a comparison study

This article considers a comparison study between different non-normal process capability estimation methods and utilizing them in the leukocyte filtering process in blood service sectors. Since the amount of leukocyte in a unit of the blood is a critical issue in the blood transfusion process and patient safety, estimating and monitoring the capability of the leukocyte filtering process to meet the target window is very important for blood service sectors. However, observed data from the leukocyte filtering process show that the leukocyte levels after filtering demonstrate a right skewed distribution and applying conventional methods with a normality assumption fails to provide trustful results. Hence, we first conduct a simulation study to compare different methods in estimating the process capability index of non-normal processes and then we apply these techniques to obtain the process capability of the leukocyte filtering process. The study reveals that the Box-Cox transformation method provides reliable estimation of the process capability of the leukocyte filtering process.