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and viability of the intended cellular product during thawing and fi nal preparation steps.
9.4.2.4 Leukocyte reduction
Whole blood may be fi ltered for leukocyte reduction prior to centrifugation. Filtration of whole blood reduces the level of platelet and leukocyte
contamination in plasma and red-cell concentrate preparations. Alternatively, components e.g. red cells, platelets may be fi ltered after separation. The
introduction of any leukocyte reduction process either by fi ltration or special centrifugation technique requires careful validation that takes national
requirements into account.
In addition to fi lter properties, the fi nal result of fi ltration is infl uenced by several process parameters e.g. fl ow rate, temperature, priming and
rinsing and by the properties of the component to be fi ltered e.g. storage history of the component, number of leukocytes and number of platelets.
The fi ltration procedure should incorporate manufacturing specifi cations such as height and temperature. The method should be fully validated under
the conditions to be used. Careful attention should be given to the rate of fi ltration. Rapid or slow fi ltration may indicate process failures.
Special centrifugation or fi ltration techniques of leukocyte reduction are used in several apheresis systems. When a standardized procedure is established on the
apheresis system, the method should be validated under the conditions to be used.
An appropriate method should be used for leukocyte counting after leukocyte reduction. The method should be validated to ensure linearity,
accuracy and reproducibility.
9.4.2.5 Irradiation
Regular dose-mapping of irradiation equipment should be performed. The exposure time should be set to ensure that all blood and blood components
receive the specifi ed recommended minimum dose, with no part receiving more than the maximum recommended dose. The common recommended
minimum dose is 25 Gy 2500 cGy.
Care should be taken regarding the increased potassium leakage from red cells after their irradiation, either by limiting the shelf-life of the red-cell
concentrate or by further manufacturing steps such as washing.
For the radioactive source, allowance should be made at least annually for source decay. A second independent timing device should be used to
monitor exposure time.
Radiation indicators should be used as aids to differentiating between irradiated and non-irradiated blood and blood components. A defi ned
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procedure should ensure the separation of components that have not been irradiated from those that have been irradiated, and should ensure they have
distinctive labelling.
9.4.3
Blood and blood components
Blood components may be obtained using the methods described in section 9.4.2. However, the sequence and the combination of the methods used in
the production of blood components may vary from one product to another.
The collection process itself is already crucial for the quality of blood components. Measures such as a reliable arm-cleaning and disinfection
procedure, the use of closed and sterile collection systems, and appropriate microbiological controls should be implemented. Time limits should be
defi ned for the processing of blood components.
There are detailed recommendations concerning the preparation and quality assurance of blood components. See for instance Guide to the preparation,
use and quality assurance of blood components of the Council of Europe 13. In the following sections, examples of the most important blood
components are described. Where NRA requirements exist, they should be followed. Specifi cations of a number of products are described below.
9.4.3.1 Whole blood
