Platelets can be prepared from whole blood donations by separating platelet-rich plasma and concentrating the platelets, or through apheresis from single donors using centrifugation to collect platelets while returning other components to the donor. Random donor platelet concentrates contain 5.5-8.5 billion platelets in 50mL plasma but also contain white blood cells, while single donor apheresis platelets contain over 3 billion platelets in 200mL plasma and fewer white blood cells, requiring no leukoreduction. Both can be stored for 5 days but apheresis platelets offer advantages like reduced pooling and donor exposures.

2.  Platelets for transfusion can be prepared either by separation of platelet
concentrates from whole blood or by Apheresis from single donors. Comparative
studies have shown that post-transfusion increment, platelet survival and
hemostatic effect are similar with either product.

3.  Platelets prepared from whole blood are often referred to as Random donor
platelet concentrates.
 Platelets rich plasma is separated from red blood cells by centrifugation at a low G
force within 4 hours after donation.
 Platelet rich plasma is then centrifuged at higher G force and most of the platelet
poor plasma supernatant is removed.
 The remaining platelet concentrate contains between 5.5 and 8.5 X 1010 platelets
suspended in about 50 mL of plasma. This is approximately 70% of the platelets in
the original unit of whole blood.

4.  Platelets are stored at room temperature using continuous gentle horizontal
agitation in plastic bags designed to optimize oxygen and carbon dioxide
exchange. Platelets can be preserved for 5 days under these conditions. Platelet
concentrates are pooled immediately prior to transfusion and can then be stored
for 4 hours.
 One drawback of random donor platelets is that the concentrates contain 108 to
109 white blood cells or approximately 50% of the leukocytes from the original unit
of whole blood. Random donor platelets should be transfused through a bedside
leukocyte reduction filter.

5. BEDSIDE LEUKOCYTE
REDUCTION FILTER

6.  Random donor platelet concentrates may contain up to 0.5 mL of red cells.
Transfusion of as little as 0.03 mL of RBCs can stimulate anti-D synthesis.
 Different studies have demonstrated that 8 to 19% of Rh negative cancer patients
form anti-D antibody if transfused with Rh positive platelet concentrates.
 Rh negative units should be used for Rh negative female children and women of
childbearing age.
 If this is not possible then one vial of Rh immune globulin may be given before or
immediately after transfusion with Rh positive platelets.
 Because these patients are thrombocytopenic, it is preferable to administer anti-D
intravenously.
 A dose of 25 ug (125 IU) will protect against 1 mL of RBCs.

7.  Apheresis platelets are usually called single donor platelets because they are collected
from a single donor with an automated cell separator.
 Donors usually have an IV line in each arm.
 Blood pumped from one arm passes through a blood cell separator centrifugation
system that collects platelets and returns plasma and red cells to the donor’s other
arm.
 Between 4000 and 5000 mL of blood are processed over 1.5 to 2 hours.
 A single donor platelet concentrate contains a minimum of 3.0 X 1011 platelets
suspended in approximately 200 mL of plasma, which is the equivalent of 6 to 8
random donor platelet concentrates.
 They can be stored up to 5 days under the same conditions as random donor platelet
concentrates.
 Five day old apheresis platelets produce the same post transfusion platelet increment
as one day old units.

9.  Single donor apheresis platelets contain fewer than 5 x 106 white blood cells and
are considered to be leukocyte reduced.
 Additional leukocyte reduction filtration is not necessary.
 Rh negative patients do not need Rh immune globulin after transfusion of Rh
positive apheresis platelets because they contain so few red blood cells (0.001 –
0.007 mL).

10.  Single donor platelets offer several advantages over random donor concentrates
including:
 Less inventory and pooling
 Fewer donor exposures & fewer lookback investigations
 Leukocyte reduction during collection eliminates the need for bedside filtration.
 Ten fold lower risk of bacterial contamination & 5 fold lower risk of septic transfusion
reaction.
 Easier platelet cross-matching or HLA matching for refractory patients.
 Fewer contaminating red blood cells eliminating need for RhIg.
 Apheresis platelets have a higher processing fee than random donor platelets, but the
cost difference is negligible when pooling and leukocyte reduction filter costs are
considered.