During blood donation, blood donors donate blood voluntarily. The blood can then be used in healthcare for, for example, blood transfusions, which requires blood products compatible with the patient. The presence of leukocytes in blood products increases the risk of febrile transfusion reactions in transfused patients. Therefore, leukocyte-reduction in blood products is necessary during production. Each blood center must perform quality control on produced blood products.
With the analysis B-leukocyte particle concentration (LPK), the total number of leukocytes in whole blood can be calculated. Flow cytometry is a method that can analyze the optical and fluorescent properties of, for example, cells in a suspension, which can be used to quantify cell numbers. The BD Leucocount™-Kit (BD Biosciences) is intended for flow cytometric analysis of the number of leukocytes remaining in leukocyte-reduced blood products.
When producing blood products, the whole blood bag should rest at room temperature for at least three hours after the donation. In Falun, either a day program is used where production takes place on the same day as the blood was donated, or an overnight program where production takes place the next day. Samples from 505 controlled erythrocyte units, collected in Falun, have shown a difference in leukocyte concentration depending on the program used.
The reason why the leukocyte content of erythrocyte units differs is not known. The purpose of this study is therefore to investigate whether the resting period has any effect on the leukocyte concentration in whole blood bags.
The LPK varied between the whole blood bags. An increasing leukocyte count was observed over time in most of the whole blood bags. However, hypothesis testing did not show statistical significance.
The hypothesis that leukocyte counts increase goes against basic hematology. Based on the results of this study, the hypothesis cannot be proven. Further studies should be conducted.