What is the X in X-mas?
cross matching or crossmatching
A test for determining the compatibility between the blood of a donor and that of a recipient before transfusion; the clumping of red blood cells indicates incompatibility.
A test for determining tissue compatibility between a transplant donor and the recipient before transplantation, in which the recipient's serum is tested for antibodies that may react with the lymphocytes or other cells of the donor.
The process of performing one of these tests.