Transfusion medicine handbook

4. Blood Components

4.5 Cytomegalovirus (CMV)

Prior to the introduction of routine prestorage leucodepletion, CMV was readily transmitted by transfusion. CMV can cause severe and even fatal disease in certain immunocompromised patients not previously exposed to the virus. Such patients should receive CMV ‘safer’ blood components, i.e., components that have undergone prestorage leucodepletion or found to be CMV-antibody negative.

The use of either prestorage leucodepletion or selection of CMV-antibody negative blood components, obtained from regular donors who have donated at least once in the preceding 6 months, significantly reduces the risk of CMV transmission and CMV disease in susceptible recipients. However, neither method alone or in combination can completely avoid transmission from the occasional donor with CMV viraemia in the "window" period prior to the development of antibodies following acute infection or when reactivation of latent infection occurs.

Since all blood components in New Zealand are leucodepleted, NZBS has adopted a policy that restricts the requirement for the use of blood components from CMV-antibody negative donors to:

• Intrauterine and neonatal transfusion.
• A selected individual patient following discussion and agreement between the treating clinician and a NZBS Transfusion Medicine Specialist / Medical Officer.