The surfaces of red blood cells display minor blood group antigens in addition to the major ABO blood group antigens.
Some people develop antibodies to non-ABO antigens following transfusion or pregnancy. This is especially true in people who may receive repeated blood transfusions, such as those with sickle cell disease.
The development of such antibodies can cause red blood cell destruction if red blood cells with the corresponding antigens are later transfused.
Development of antibodies to non-ABO antigens can be prevented by selecting blood that is better matched to the patient‘s non-ABO antigens. In addition, when a potential transfusion recipient has a known antibody that causes red blood cell destruction, red blood cells that are negative for the corresponding antigen must be found.
The identification of red blood cell antigens has traditionally been performed by serological typing. This involves testing blood with reagents (antisera) that are specific for the antigens for which the blood is being tested. However, specific antisera may be scarce or unavailable.
A new and alternative method has been approved. It works by detecting genes that govern the expression of 36 antigens that can appear on the surface of red blood cells. The test uses thousands of coded beads that bind with the genes coding for non-ABO red blood cell antigens that are present in a blood sample. A light signal is generated from each bead that has captured a specific gene. Accompanying computer software decodes the light signals and reports which antigens are predicted to be present on the red cells based on the genes that are detected.
Performance is comparable between the two methods.