I asked many questions while I was there too. This means that if I did not match my friend, one day I could be asked to donate to a perfect stranger. I was uneasy about this at first, but my primary thought was my friend and this was the only way I could know if we matched. A vial of blood was drawn. My fear of needles was pushed aside and the nurses were patient and sweet through it all as they comforted me.
Blood is tested to match six antigens.
Antigens are proteins found on cells that give each cell its identity, so to speak. The more Antigens that match, the less chance there is of rejection. The best scenario is a 6 Antigen match and that is the goal when a patient searches the National Registry. Even a 6 Antigen match does not guarantee that the cells will not be rejected. For minority groups these odds are much higher.