Information about donation by relatives or friends (directed donation)
Information for clinical staff who may be called on to discuss this with patients and parents
The UK transfusion services generally discourage donation by parents, relatives or friends (so-called ‘directed donation’) for good medical and scientific reasons. Patients or parents may assume that there is a lower risk of disease transmission if the chosen person’s blood is used rather than blood from the blood bank. However, published data show that blood from voluntary donors is in fact likely to be safer for the patient.
It is essential to discuss the following potential problems with the individuals concerned.
- The ‘directed’ donor may be inhibited from giving frank answers to questions about risk factors for infections. Studies show that directed donors do not have a lower risk of infectious disease transmission (based on positive tests for hepatitis or HIV). In fact, in some studies there has been a higher incidence of markers of infection in those who want to be directed donors than in the normal donor population. This is especially a concern when the directed donor is a first-time donor rather than a regular blood donor, as there is no history of previous testing.
- The donor may not have a blood group that is compatible with the patient’s.
- Donors who are first- or second-degree relatives of the patient have a relatively high likelihood of having a similar tissue type − brothers and sisters have a 1 in 4 chance of being a ‘complete match’, parents and children of the patient will be at least ‘haploidentical’, i.e. matched for 50% of the tissue type. Thus there is a risk of the recipient developing graft-versus-host disease, which is a fatal condition (see Transfusion associated graft-versus-host disease). For this reason all donations from related donors must be irradiated before transfusion to kill any remaining white cells.
- There are additional concerns when a mother wishes to donate for her child, in which case she should be aware that she may have antibodies to the baby’s blood cells (red cells, white cells, platelets) and therefore that transfusion of her blood could cause the baby to suffer an acute or delayed transfusion reaction, respiratory problems, or a low platelet count.
- Transfusion of blood from a father to a young baby may also lead to a transfusion reaction, as the baby may have maternal antibodies.
- Older children may already have been sensitised against the mother’s blood cells, as there is some passage of cells from the mother into the baby during pregnancy. This fact is less well known than the recognised risk of the baby’s cells passing into the mother’s bloodstream but also carries some potential risks. For example, if cells from the mother are transfused into an older child, there is a possibility that this will act as a ‘booster’ injection. The child may develop high levels of antibodies within a few days and break down the mother’s transfused blood cells.
- Transfusion of a partner’s blood to a patient who is or has been pregnant can cause acute reactions similar to those seen in the neonatal situation, as the woman may have developed potent antibodies to the partner’s cells as a result of the pregnancy. In addition, the woman may develop antibodies after the transfusion, which may cause problems to the baby in future pregnancies.
- It is essential to make quite clear that if a directed donation is to be accepted, the donor must fulfil all of the criteria used to select normal volunteer donors, and that an individual who does not pass the normal donor screening processes will not be accepted as a directed donor.