JPAC Joint United Kingdom (UK) Blood Transfusion and Tissue Transplantation Services Professional Advisory Committee

7.9: Platelets, Pooled, Buffy Coat Derived, Leucocyte Depleted

Update notice: Sections 7.9.3, 7.9.4 and table 7.6 have been updated following the the issue of Change Notification 18 - 2015.  Further changes have also been made to the concessionary release limits in table 7.6 following the the issue of Change Notification 22 - 2015.
The tables in the sections 7.9.4, 7.10.4, 7.11.4, 7.12.4, 7.29.4 and 7.30.4 have been updated following the issue of Change Notification No 34 – 2016.

A pool of platelets, derived from buffy coats, which contains less than 1 × 106 leucocytes.

7.9.1: Technical information

  • Donations of whole blood where the bleed time exceeded 15 minutes are not suitable for platelet production.
  • The buffy coats must be prepared at ambient temperature from whole blood where the surface temperature of packs has not dropped below 18°C.
  • Initial separation of buffy coat must occur within 24 hours of venepuncture (unless supported by additional validation), with a minimum buffy coat rest period of 2 hours before secondary pooling and processing of buffy coats to produce the final component, which is 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 a full audit trail and that 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 9). Plasma should be selected from male donors as a TRALI risk reduction strategy.
  • Platelets, Pooled, Buffy Coat Derived, Leucocyte Depleted, should be transfused through a 170–200 μm filter.                                                                                                                 

7.9.2: Labelling

For general guidelines, see section 6.6.

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, including vCJD

7.9.3: Storage

For general guidelines, see section 6.7.

  • 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 ±2°C with continuous gentle agitation for up to 5 days in a closed system. Appropriate pack and platelet concentration combinations may allow storage up to 7 days, but due to concerns over bacterial contamination requires 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 ±2°C with continuous agitation and used within 6 hours.
  • Platelets should be gently 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 interruptions are for no longer than a total of 24 hours and no single interruption lasts for more than eight hours.

7.9.4: Testing

In addition to the mandatory and other tests required for blood donations described in Chapter 9, and leucocyte counting (see sections 6.3 and 7.1), a minimum of 75% of those components tested for the parameters shown in Table 7.6 shall meet the specified values.

Table 7.6 Platelets, Pooled, Buffy Coat Derived, Leucocyte Depleted – additional tests

Parameter Frequency of test Specification


1% or as determined by statistical process control
(if ≤10 components produced per month then test every available component)

Within locally defined nominal volume range**

Platelet count

≥240 × 109/pool***

pH at end of shelf life****

≥ 6.4

Leucocyte count*

As per sections 6.3 and 7.1

<1 × 106/pool

* Methods validated for counting low numbers of leucocytes must be used

** Units measured and found to be outside of the range 150 to 380 mL should not be issued for transfusion

*** Units tested and found to have <160 × 109/pool should not be issued for transfusion

**** A minimum of 95% of components tested shall meet the specified values

Note: Visual inspection of platelet components for the swirling phenomenon, clumping, excessive red cell contamination and abnormal volume is a useful pre-issue check.

7.9.5: Transportation

For general guidelines, see section 6.11.

  • 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 ±2°C with continuous gentle agitation.
  • Plastic overwraps should be removed prior to storage.