Introduction: Leukocytes causing a wide variety of side effects after transfusion are present in all blood products prepared by standard methods. As a consequence, the use of filter technology for leukoreduction has been widely practiced .According to AABB accreditation in 1996, leukoreduced blood components must contain less than 5×106 leukocytes per unit, but sometimes this value is higher even in leukoreduced products. In this study we did absolute leukocyte count in filtered (home made bedside filter) packed cell units by two methods of true count as standard method and CD45 MoAb.
Materials & Methods: 93 packed cell units were stored at 4°c and filtered by two types of home-made filters according to manufacturer's instructions. Furthermore, eight packed cell units were filtered by Europe certified control group filters (bio-fil). Sample preparation was done according to True count kit and CD45 MoAb procedures and analysis was performed by flowcytometry (EPICS-XL,coulter) and (Partec PAS III).The results were then analyzed by chi2 test via SPSS.
Results: The mean values of leukocyte count/unit by anti CD45 and True count method were 9×106 and 10×106 respectively in 55 pre-revised filter bags these figures were 4.2×106 and 4.8×106 in 30 post-revised filters, whereas the mean leukocyte count/bag in eight control filters was 2.3×106,we selected randomly eight test units out of 53 and 30 pre-revised and post-revised filtered bags, respectively(equal with number of units in the control group) to compare the test and control groups The mean values of leukocyte count/bag in pre-revised test group was 7.9±5.4×106 and in postrevised test group was 4.2 ×106 but in the control group it was 2.3 ×106 (p value<0.05).
Discussion: According to the results, the mean leukocyte count/bag in pre-revised group was higher than AABB standard. 38.2 % of bags had lower and 61.8 % had higher leukocyte count than the standard value (48.9 to 74.6 % with CI=95 %), this indicates the necessity of revision in product technology of homemade filters. relevant manufacturer revised the product technology and material accordingly, so that new filters (post-revised group) reduced leukocytes within standard limits (leukocyte count in 6 bags were out of standard range).In post-revise filter group, 20 % had a leukocyte count of more than 5×106 while 80% showed less than this value (5.7%-34.3% with CI=95%).There is a significant difference between control and pre-revised test groups (p=0.03).In post-revised test group, despite significant differences, the mean values of leukocyte count/bag were within normal standard range. The results of this research caused home-made filter production with higher quality.