Test Details: Human leukocyte antigens (HLA) are a system of glycoproteins that have a functional role in the presentation of peptides to the immune system. However, as a highly polymorphic system, HLA molecules can become the targets of antibody responses in people during pregnancy, transfusion of blood products, or organ transplant rejection. Generally, alloimmunization leads to the production of HLA antibodies in approximately 33% of exposed individuals. The presence or absence of these HLA-specific antibodies has negative effect on survival of transplant allografts. Flow cytometry cross match (FCXM) utilizes flow cytometric method to measure alloantibodies in the potential recipient that are directed against the donor lymphocytes. It is a sensitive assay which can detect both complement and non- complement fixing antibodies. It can discriminate between T-cells and B-cells.