Section 8.14

8.14 Fresh Frozen Plasma, Methylene Blue Treated and Removed, Leucocyte Depleted

Fresh Frozen Plasma Methylene Blue Treated (MBT) and Removed, Leucocyte Depleted, is plasma that has been obtained from whole blood or by apheresis from a previously tested donor (as defined in Section 8.3), contains less than 5 x 10⁶ leucocytes and has been treated with methylene blue and exposure to visible light to inactivate pathogens.

Following methylene blue treatment and removal, the plasma is rapidly frozen to a temperature that will maintain the activity of labile coagulation factors.

Technical information

Where the starting component is sourced outwith the UK, a detailed and agreed specification must be available.

Donations of whole blood where the bleed time exceeded 15 minutes are not suitable for the production of plasma components for direct clinical use.

Ideally the plasma should be separated before the red cell component is cooled to its storage temperature.

The method of preparation should ensure the component has the maximum level of labile coagulation factors with minimum cellular contamination.

Intact white blood cells in the plasma should be reduced to less than 5 x 10⁶ per unit prior to exposure to methylene blue and visible light.

The production process should be validated to ensure that components meet the specified limits for FVIII:C content.

Greater FVIII:C yields will be obtained when the plasma is separated as soon as possible after venepuncture, MB treated and rapidly frozen to –25°C or below.

Component samples collected for the Quality Monitoring assessment of FVIII:C should have approximately the same ABO group distribution as issued components.

The MBT process reduces the FVIII:C content by approximately 30% when compared to standard FFP.

The process for methylene blue removal should be validated to give components with a methylene blue concentration =0.30 µM (< approximately 30 µg per unit).

Component samples collected for the Quality Monitoring assessment of FVIII:C should have approximately the same ABO group distribution as issued components.

Fresh Frozen Plasma, Methylene Blue Treated and Removed 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.)

fresh frozen plasma, methylene blue treated and removed, Leucocyte Depleted* and volume

the blood component producer's name*

the donation number*

the ABO group*

the RhD group stated as positive or negative*

the date of collection

the expiry date of the frozen component*

the temperature of storage

the blood pack lot number*

a warning that the component should be used within four hours of thawing

the name, composition and volume of the anticoagulant.

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 component should be stored at a core temperature of –25°C or below for a maximum of 24 months.

Although a storage temperature below –25°C improves the preservation of labile coagulation factors, lower temperatures increase the fragility of plastic. Particular care must be taken when handling such packs.

The component should be thawed in a waterbath or other equipment designed for the purpose, within a vacuum sealed overwrap bag according to a validated procedure. The optimal temperature at which the component should be thawed is 37 °C; temperatures between 33 – 37 °C are acceptable. Protocols must be in place to ensure that the equipment is cleaned daily and maintained to minimize the risk of bacterial contamination. After thawing, the content should be inspected to ensure that no insoluble cryoprecipitate is visible and that the container is intact.

Once thawed, the component must not be refrozen and should be transfused as soon as possible. If delay is unavoidable, the component may be stored and should be used within 4 hours if maintained at 22 ± 2°C or 24 hours if stored at 4° ± 2°C, but it should be borne in mind that extended post-thaw storage will result in a decline in the content of labile coagulation factors.

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 8.11 shall meet the specified values.

*Methods validated for counting low numbers of leucocytes must be used.
**Prefreeze in starting component.