Preparation of Platelets
Canadian Blood Services produces two platelet components:
Following the implementation of the Buffy Coat Production Method (BCPM), another platelet product will be available:
Preparation of CP2D Platelets
CP2D Platelets are prepared from a single unit of whole blood collected in CP2D. This product is also known as random donor platelets.
If platelet preparation is intended, the donor unit must be bled into a specific multiple bag system designed for this purpose. Below is a simple schematic of how random donor platelets are prepared.
The whole blood donation is centrifuged at room temperature to separate red cells from plasma.
Centrifugation at room temperature (20-24° C) is required to prevent the platelets from aggregating. A “light spin” is used to keep the platelets suspended in plasma.
Approximately 190-260 mL of donor plasma is expressed through a filter into the first satellite bag to produce platelet-rich plasma (PRP).
The RBC unit and additive pack are separated from the PRP and sent for preparation of AS-3 RBC LR. Following filtration, the RBC unit is sealed and stored at 1-6° C for 42 days.
The PRP is centrifuged at room temperature using a “hard spin” to concentrate the platelets.
All but approximately 50 mL of plasma is expressed into the second satellite bag.
The supernatant (platelet poor) plasma is stored at temperatures of less than -20° C as Fresh Frozen Plasma, LR for up to 12 months. The plasma may also be shipped as recovered plasma for further manufacture.
The platelet units rest at room temperature for one to two hours to recover from the preparation manipulations. The platelet units are then stored on a platelet agitator in a room temperature incubator.
Additional information on Platelets, LR may be found in the Circular of Information for the Use of Human Blood and Blood Components -2004
Preparation of Platelet Apheresis
Platelet Apheresis, LR are collected from single donors using automated apheresis techniques, which include steps to separate leukocytes. Platelet Apheresis, LR are supplied in one 400mL container.
Additional information on Platelet Apheresis, LR, may be found in the Circular of Information for the Use of Human Blood and Blood Components - 2004 and 2005
Preparation of CPD Platelets
Below is a simple schematic of how CPD Platelets Pooled, LR are prepared from a whole blood collection using the buffy coat production method. Not shown is the procedure for leukofiltration.
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Step 1 |
The whole blood donation is centrifuged using a “hard spin” to separate red cells from plasma. The buffy coat layer containing the platelets appears as a thick white layer above the red cells.
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Step 2 |
Using the component separator (Compomat G4) RBCs and plasma are extracted from the buffy coat (from the bottom and top of the primary bag respectively).
Red cells and plasma are forwarded for further processing. |
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Step 3 |
The buffy coats are allowed to rest for a minimum of two hours.
Four buffy coats with the same ABO group and plasma from one of the same four buffy coats are grouped together for pooling. |
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Step 4
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The buffy coats and plasma are sterile docked together in the “train” method.
The platelet storage container with filter is sterile docked to the last buffy coat in the train. |
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Step 5 |
The buffy coats and plasma are pooled together using the “train” method. | |
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Pooled buffy coats are centrifuged using a “soft spin” to separate platelet rich plasma from the plasma containing the majority of the white blood cells. | |
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Step 7 |
Platelets (platelet rich plasma) are extracted and filtered using the Compomat G4 | |
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Step 8 |
CPD Platelets, Pooled, LR is similar in physical size to an apheresis platelet concentrate The platelets are placed on a platelet agitator for storage. Sampling for potential bacterial contamination is obtained at this time |
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Additional information on CPD Platelets, Pooled, LR may be found in the Circular of Information for the Use of Human Blood and Blood Components - 2005