The blood of a person who has never had CMV (cytomegalovirus) will test negative for antibodies to the infection and will be described as having CMV-negative blood. Interestingly, many people who contract CMV never know they have it.
Cytomegalovirus is a common herpes virus that infects people of all ages all over the world. It infects between 50 and 80 percent of adults in the United States by the time they are 40 years of age, according to the Centers for Disease Control (CDC).
Blood products that are CMV negative are important to patient populations that would be in particular danger if they contracted CMV. That includes transplant recipients, pregnant women and infants.
Donated blood is not automatically tested for CMV. Blood products may instead be tested when a patient is in need of blood.
Blood banks maintain lists of those they know have CMV-negative blood, so they will be able to contact a donor when a need for CMV-negative blood arises.
If a person has had CMV once, they have the herpes virus in their system for life, so that person has no need to receive CMV-negative blood products.