Radio Solutions Questions from 4BC

Does your DNA change when you have a blood transfusion?

No it doesn't. Here's why. Blood is made up of 4 elements – red blood cells, white blood cells, plasma and platelets. Most blood transfusions only involve red blood cells or plasma which do not contain any DNA at all. Whilst white blood cells do contain DNA however, even in rare whole blood transfusions there is no permanent change of DNA – it might be slightly skewed for a couple of days, however the recipients DNA takes over after a couple of days.

There is however a situation in which a transplant can change your DNA - a bone marrow transplant. The DNA in a blood sample from someone who has had a bone marrow transplant may actually reflect the donor rather than the recipient. The reason for this is because the actual blood stem cells are transferred after all the recipients cells have been killed off with treatment. Because of this, the recipient will produce blood that contains the donor's cellular elements and almost none of his or her own DNA.

This doesn't affect other DNA such as saliva etc, only the blood. In these cases a person will have two sets of DNA.