Can Platelets Be Transfused Without a Filter?
Yes, platelets can be transfused without a leukoreduction filter if they have already undergone prestorage leukodepletion, which is now the standard practice in the United States and many other countries. 1
Current Standard Practice
Prestorage leukodepletion eliminates the need for additional filtration at the time of transfusion, as this process removes leukocytes before storage at the blood bank level. 1
The American Society of Clinical Oncology confirms that prestorage leucodepletion is the standard in the United States and many other countries, providing more consistent quality control than bedside filtration. 1
When platelets are already leukoreduced during processing, no additional filter is required at the bedside for transfusion. 1
Important Distinction: Leukoreduction vs. Standard Filters
Standard Blood Administration Filters (170-200 μm)
Standard 170 μm pore blood transfusion filters do NOT remove microaggregates or leukocytes effectively and are not designed for leukoreduction. 2
These standard filters are incorporated into routine blood administration sets but serve primarily to remove large debris, not to achieve leukoreduction. 1
Leukoreduction Filters
If platelets have NOT been prestorage leukoreduced, then leukoreduction filtration should be performed to prevent alloimmunization, particularly in patients with acute myeloid leukemia or those requiring long-term transfusion support. 3
Leukoreduction via filtration achieves a 3 to 4 log reduction in leukocyte contamination, reducing alloimmunization rates from 45% to 17-21%. 3
Clinical Caveat: Microaggregate Filters
Microaggregate filters (40 μm) should NOT be used with already leukoreduced platelet products, as they are unnecessary and may cause significant platelet loss (up to 25-35%). 4, 3
One older study suggested microaggregate filters prevented post-transfusion platelet count drops in thrombocytopenic patients receiving red blood cell transfusions, but this is not applicable to modern leukoreduced platelet concentrates. 5
Bottom Line
In modern transfusion practice with prestorage leukoreduced platelets, no additional filtration is required at the bedside beyond the standard blood administration set. 1 The leukoreduction has already been accomplished during processing, making bedside leukoreduction filters redundant and potentially harmful due to platelet loss. 4