8.10 Platelets, Apheresis, Leucocyte Depleted
A single donor platelet component containing less than 5 x 106 leucocytes.
Technical information
Platelets, Apheresis may be collected by a variety of apheresis systems using different protocols. Since platelet yields may vary, each procedural protocol must be fully validated, documented and specifications set accordingly.
If filtration is used the recommended capacity of the filter should not be exceeded.
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.
If the leucodepletion process transfers the final component into a pack that was not part of the original pack assembly, a secure system must be in place to ensure the correct identification number is put on the final component pack.
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, Apheresis, Leucocyte Depleted should be transfused through a 170–200µm 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, apheresis, Leucocyte Depleted* and volume
the blood component producer's name*
the donation number and, if divided, sub-batch number*
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:
INSTRUCTION
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 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.
Where any manufacturing step involves an open system the platelets should be used as soon as possible after collection. 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.
Testing
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 8.7 shall meet the specified values.
Table 8.7 Platelets, apheresis, 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 per unit |
| 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 per unit |
* 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.