Prestorage leukoreduction does not increase hemolysis of stored red cell concentrates

In December 2004, Pall Corporation initiated voluntary recall of certain filters used for leukocyte-reduction of blood products. Although our center had not used the implicated lots, certain customers reported observing increased hemolysis in the red-cell units (RC) provided by us. The purpose of this study was to determine the level of hemolysis seen in RC produced by our center.

In the first-phase, we evaluated 20 leukocyte-reduced (LR)-RC, those judged by one of our hospitals to have the highest degree of hemolysis (age: 10-30 days; average=16 days). Results were compared to ten randomly selected non-LR-RC (age: 10-19 days; average: 15 days). Samples obtained directly from the RC were tested for hemoglobin (Hb), hematocrit (Hct) and supernatant-Hb. Percent-hemolysis (% hemolysis) was calculated. In the second-phase, the above measurements were made on 70RCs. Ten RCs were studied before and after leukofilteration on day-2 after collection. Ten units each (LR & non-LR) were selected randomly from inventory at days: 15, 30 and 40 after collection (LR-units filtered within 48 h).

In the first-phase LR-RCs exhibited an average 0.06% hemolysis vs. 0.02% for non-LR units. In the second-phase the average % hemolysis before and after filteration on day-2 (LR: 0.04% & non-LR: 0.04%) was similar. While on days: 15 (LR: 0.09%, non-LR: 0.05%) and 30 (LR: 0.16%, non-LR: 0.13%) % hemolysis was slightly more in LR as compared to non-LR. It was the opposite for day 40 (LR: 0.19%, non-LR: 0.31%). However, none of these differences were statistically significant.

The % hemolysis increased as the age of the unit increased. There was no significant statistical difference between LR-RC and non-LR-RCs. This data did not confirm our hospitals' concerns regarding increased hemolysis following LR.