ABSTRACT
BACKGROUND: The efficiency of leukocyte removal filter is influenced by many factors. But, filtration efficiency of leukocyte fragments was not well known. We performed this study to evaluate whether the filtration efficiency for packed red blood cells can be influenced by leukocyte fragments according to storage time. METHODS: Leukocyte fragments in packed red blood cells (three units) which were artificially made by incubation for 4 hrs at 56degrees C and each four units of packed red blood cells according to storage time (0 days, 10 days, 20 days, and 30 days) were filtered using Sepacell R-500A (Asahi medical Co, Japan). The leukocyte concentrations of the pre-leukodepleted samples were estimated using an automated hematology analyzer (XE-2100, Sysmex, Japan). The ratio between the number of normal leukocytes and leukocyte fragments on Wright Giemsa stained slide was used in the analysis. The leukocyte concentrations of the post-leukodepleted samples were performed by the conventional counting methods using Nageotte hemocytometer. RESULTS: The ratios of fragmented to total leukocytes in packed red blood cells at pre- and post leukoreduction according to storage times were 1.5% and 16.3% within 1 days, 4.5% and 30.0% at 10 days, 6.3% and 35.0% at 30 days, and 8.3% and 42.5% at 40 days, respectively. Leukoreduction efficiencies of normal leukocytes in packed red blood cells were 99.99 +/- 0.01%, 99.97 +/- 0.02%, 99.98 +/- 0.01%, and 99.86 +/- 0.09%, respectively. The 36.0% of leukocytes in packed red blood cells were changed to fragmented leukocytes, residual fragmented leukocytes ratio was 95.0% and filter efficiencies of normal leukocytes was low(99.28%, p<0.05). CONCLUSIONS: The leukodepleted efficiency for leukocyte fragments were lower than for normal leukocytes. Leukocytes fragments may be influenced to lower the leukodepleted efficiency of normal leukocytes with storage time elapse.