Irradiated blood components are products that have been exposed to irradiation for the purpose of inactivating the T lymphocytes (a type of white blood cell).

At the same time, the radiation dose must inactivate the reaction capacity (proliferation) of the donor’s immunocompetent cells and preserve the therapeutic qualities of the irradiated product. The optimal dose was determined experimentally by measuring these two parameters. In Canada, the dose ranges from 15 to 50 Gy (1,500 to 5,000 rad) with a minimum dose of 25 Gy (2,500 rad) toward the median plane.

Action

Irradiated blood components are used to prevent the graft-versus-host (GVH) reaction.

Main indications

Irradiated products are indicated under the following conditions:

• HLA-compatible blood products;
• granulocytes;
• blood products from donors with a first- or second-degree relationship with the recipient (directed donations).

For medical indications requiring irradiated blood products, refer to the NAC-CCNMT’s recommendations about irradiation of blood products.

Contraindications

Irradiation causes the accumulation of potassium, which could have harmful effects in newborns and people with severe kidney failure. To minimize the risk of hyperkalemia, it is recommended, if possible, that the packed red blood cells be irradiated just before they are administered. In patients with a high risk of complications due to hyperkalemia (e.g., massive transfusion in a child less than 10 kg), supernatant removal or a simple red blood cell washing procedure are measures that can be considered for reducing the risk.

Routine irradiation of blood products is not desirable, but in recipients at risk of a graft-versus-host reaction, the advantages outweigh the disadvantages.

Dosage and administration

Refer to the dosage and administration specific to each product.

Storage

The irradiated packed red blood cells must be kept between 1°C and 6°C. They must be transfused no later than 14 days after being irradiated and no later than 28 days after collection.

Platelets can be irradiated at any time and kept for their usual lifespan of 7 days. Bags of platelets must be stored between 20°C and 24°C and be gently and continuously agitated during the storage period.

Granulocytes must be irradiated as soon as possible after they are produced and used as soon as possible. The product must be stored without agitation between 20°C and 24°C for a period no longer than 24 hours.

Blood products intended for intrauterine transfusion must be transfused within 24 hours after irradiation.

In the event of a discrepancy between the information on this page and what is in the Circular of information, the latter will take precedence.