cross-matching

1. A test for incompatibility between donor and recipient blood, carried out prior to transfusion to avoid potentially lethal hemolytic reactions between the donor's red blood cells and antibodies in the recipient's plasma, or the reverse; performed by mixing a sample of red blood cells of the donor with plasma of the recipient (major crossmatch) and the red blood cells of the recipient with the plasma of the donor (minor crossmatch). Incompatibility is indicated by clumping of red blood cells and contraindicates use of the donor's blood. 2. In allotransplantation of solid organs ( e.g., kidney), a test for identification of antibody in the serum of potential allograft recipients which reacts directly with the lymphocytes or other cells of a potential allograft donor; presence of these antibodies usually, if not always, contraindicates the performance of the transplantation because virtually all such grafts will be subject to a hyperacute type of rejection.