If an offender has had a blood transfusion or a bone marrow transplant how will this affect a blood sample and the subsequent DNA profile?
When a person has a blood transfusion it will take, in some cases, a few weeks for this person to completely replace all of the transfused blood cells. There may be a mixture of both the donor and the recipient`s blood present. In order to be sure that the sample is not a mixture, wait one month before taking a blood sample. Another solution is to take a buccal swab from the offender instead. Also, in cases of bone marrow transplants, there may be a mixture of both the donor and the recipient`s blood; and if the transplant is a complete success, the recipient will have the donor`s blood type. In these rare cases, we would recommend taking a buccal swab from the offender.
