8.9 Platelets, Pooled, Buffy Coat Derived, Leucocyte Depleted
A pool of platelets, derived from buffy coats, which contains less than 5 x 106 leucocytes.
Donations of whole blood where the bleed time exceeded 15 minutes are not suitable for platelet production.
The component must be prepared at ambient temperature before the red cell component is cooled to its storage temperature.
Initial separation of buffy coat normally occurs within 12 hours of venepuncture, with secondary pooling and processing of buffy coats to produce the final component generally completed before the end of day 1.
The volume of suspension medium must be sufficient to maintain the pH within the range 6.4–7.4 at the end of the shelf life of the component.
The production process transfers the final component into a pack that was not part of the original pack assembly, therefore a secure system must be in place to ensure the correct identification number is put on the final component pack.
Where the production method requires the use of a single unit of plasma for resuspension, the plasma from group O donors should be tested for high titre anti-A and anti-B and 'high titre negative' units labelled. The testing method and acceptable limits should be defined (see also Chapter 10).
Platelets, Pooled, Buffy Coat Derived, Leucocyte Depleted, should be transfused through a 170–200 µm filter.
Labelling (for general guidelines see Section 7.5)
The following shall be included on the label:
(* = in eye-readable and UKBTS approved barcode format.)
platelets, pooled, buffy coat derived, Leucocyte Depleted* and volume
the blood component producer's name*
a unique pool or batch number or the donation number of all contributing platelet units*
the ABO group*
the RhD group stated as positive or negative*
the expiry date*
the temperature of storage and a comment that continuous gentle agitation throughout storage is recommended
the blood pack lot number*
the name, composition and volume of the anticoagulant or additive solution.
In addition, the following statements should be made:
Always check patient/component compatibility/identity
Inspect pack and contents for signs of deterioration or damage
Risk of adverse reaction/infection
Storage (for general guidelines see Section 7.6)
The storage period depends on a number of factors including the nature of the container, the concentration of platelets and on whether an open or closed system is used.
Packs currently in use for this purpose allow for storage at a core temperature of
22°C±2°C with continuous gentle agitation for up to five days in a closed system. Appropriate pack and platelet concentration combinations may allow storage up to seven days, but due to concerns over bacterial contamination would require either an assay to exclude bacterial contamination prior to transfusion or application of a licensed pathogen inactivation procedure.
If any production stage involves an open system, after preparation the component should be used as soon as possible. If storage is unavoidable, the component should be stored at a core temperature of 22°C±2°C with continuous agitation and used within six hours.
Platelets should be agitated during storage. If agitation is interrupted, for example due to equipment failure or prolonged transportation, the components are suitable for use, retaining the same shelf life, provided the interruption is for no longer than a single episode of 24 hours.
In addition to the mandatory and other tests required for blood donations described in Chapter 10, and leucocyte counting (see Sections 7.2 and 8.1), a minimum of 75% of those components tested for the parameters shown in Table 8.6 shall meet the specified values.
Table 8.6 Platelets, pooled, buffy coat derived, leucocyte depleted – additional tests
|Parameter||Frequency of test||Specification|
|Volume||1% or 10 per month, whichever is greater||Within locally defined nominal volume range|
|Platelet count|| ||≥240 x 109/pool|
|pH at end of shelf life||If less than 10 per month, every available component||6.4–7.4|
|Leucocyte Count*||As per Sections 7.2 and 8.1||<5 x 106/pool|
* Methods validated for counting low numbers of leucocytes must be used.
NOTE: Visual inspection of platelet components for the swirling phenomenon, clumping, excessive red cell contamination and abnormal volume is a useful pre-issue check.
Transportation (for general guidelines see Section 7.10)
Containers for transporting platelets should be equilibrated at room temperature before use. During transportation the temperature of platelets must be kept as close as possible to the recommended storage temperature and on receipt, unless intended for immediate therapeutic use, the component should be transferred to storage at a core temperature of 22°C±2°C with continuous gentle agitation.
Plastic overwraps should be removed prior to storage.