Update notice: text HIGHLIGHTED has changed following the issue of Change Notification 06 - 2009
8.28 Irradiated components
For the whole of this section X-irradiation may be regarded as equivalent to gamma-irradiation. Times when irradiation should be undertaken and the permitted post-irradiation storage times are the same, as are the required labeling and dosing (recommended minimum dose achieved in the irradiation field is 25Gy, with no part receiving >50Gy).
Please note that the X-ray equipment should be dose-mapped prior to release from the factory and at installation, and the manufacturers recommend routine dosimetry at 6-monthly intervals. They also manufacture a radiation sensitive label specifically for use with X-radiation.
It is not necessary to irradiate the following components:
cryopreserved red cells after washing
Irradiated components not used for the intended recipient can safely be used for recipients who do not require irradiated components provided the other requirements of Chapters 7 and 8 have been satisfied. However, any reduction in shelf life resulting from the irradiation process must be observed.
Irradiated components should conform to their appropriate specification previously given in this chapter. In addition, the guidelines shown below should be observed.
Irradiated components are components that have been irradiated by a validated procedure.
Other than for use in intrauterine or exchange transfusion, red cells can be irradiated at any time up to 14 days after collection.
Platelets can be irradiated at any stage in their storage.
Granulocytes should be irradiated as soon as possible after production.
For red cells, platelets and granulocytes the recommended minimum dose achieved in the irradiation field is 25Gy, with no part receiving >50Gy.
Platelets to be transfused in utero to treat alloimmune thrombocytopenia must be irradiated.
Laboratories performing irradiation of blood components must work to a clearly defined specification and are strongly recommended to work closely with a medical physicist. The defined irradiation procedure must be validated and there must be regular monitoring of the blood component dosimetry and the laboratory equipment.
It is recommended that irradiation of blood components is carried out using dedicated blood irradiation machines. If radiotherapy machines are used, equivalent protocols should be developed.
Gamma ray sensitive labels should be used as an aid to differentiating irradiated from non-irradiated components. However, it may not be necessary to attach a gamma ray sensitive label to every component pack provided that the irradiation procedure follows a validated, documented and well controlled system of work that is integrated to the component labelling and release mechanism and permits retrospective audit of each stage of the irradiation process.
There should be a permanent record of all units irradiated. This should include details of irradiation batch and donation numbers, component type, the site of irradiation, when irradiation was performed and by whom.
Irradiated components must be identified by the applied labelling and include the date of irradiation and any reduction in shelf life.
Labels which are sensitive to gamma rays and change from 'NOT IRRADIATED' to 'IRRADIATED' are available and are considered a useful indicator of exposure to gamma rays. The dose at which the label changes to 'IRRADIATED' must be marked on the label. It must be remembered that such labels simply reflect that the unit has been exposed to gamma rays and their use does not replace the need for regular and precise dosimetry nor carefully controlled working procedures.
Storage (for general guidelines see Section 7.6)
Red cell components, other than for intrauterine or exchange transfusion can be irradiated at any time up to 14 days after collection and stored for up to 14 days thereafter provided the other requirements of this section are adhered to.
Where irradiated red cells are intended for intrauterine or exchange transfusion or where the patient is at particular risk from hyperkalaemia, red cells should be transfused within 24 hours of irradiation. Furthermore, red cells intended for intrauterine or exchange transfusion should be transfused within five days of collection.
Irradiated platelets can be stored up to their normal shelf life of five days after collection.
Granulocytes must be irradiated and should be used with minimum delay after irradiation but within the shelf life specified earlier in this chapter.