donor
Meaning of donor: The person a transplanted organ, transfused blood or donated tissue comes from, whether living or recently deceased.
Definition of donor
A donor is a person who provides blood, cells, tissue or an organ for use in someone else. Some donations come from living people, such as blood, bone marrow, or a kidney or part of a liver. Others come from a person who has died, which is the source of most hearts, lungs, corneas and skin. Matching between donor and recipient determines whether the graft is accepted.
What can be donated, and by whom?
| Donation | Living | After death |
|---|---|---|
| Blood and plasma | Yes, replaced within weeks | No |
| Bone marrow or stem cells | Yes, marrow regenerates | No |
| Kidney | Yes, one of two | Yes |
| Liver | Part only, the organ regrows | Yes |
| Heart, lungs, cornea | No | Yes |
Why does matching matter?
The immune system inspects everything in the body for surface markers it recognizes as its own. A blood transfusion requires matching of blood group, since antibodies against the wrong group destroy the transfused cells immediately. An organ transplant requires closer matching of tissue types, and even a good match needs lifelong medication to suppress rejection. Marrow and stem cell transplants demand the closest match of all, because the transplanted immune cells can attack the recipient rather than the other way around. Relatives are more likely to match, which is why family members are tested first for marrow donation.
How does donation after death work?
Two situations are recognized. In one, the brain has died irreversibly while the heart continues to beat with mechanical support, which preserves organs in good condition. In the other, donation follows the stopping of the circulation, and the window in which organs remain usable is much shorter. Determination of death is made by clinicians independent of the transplant team, a separation designed to remove any conflict of interest. Consent arrangements vary between countries, with some operating an opt-in register and others presuming agreement unless a person has recorded an objection.
Are donors screened?
Extensively. Blood, tissue and organs are tested for transmissible infections, and medical and social history is reviewed, since some conditions can be passed on with the graft. Living donors undergo assessment of their own health and of their understanding of the risks, and independent review of consent is standard where a living person gives an organ. Some donation is directed to a named person; much of it is anonymous.
Used in a sentence
A living related donor was identified after tissue typing of family members.
Good to know
Determination of death is made by clinicians independent of any transplant team, and the closeness of matching required rises from blood group for transfusion to detailed tissue typing for marrow.
Word origin
Where “donor” comes from
From the Latin donare, meaning to give.