Test Details: Single antigen beads (SAB) are commonly used to provide semi-quantitative assessments of HLA antibodies for estimation of pretransplant risk and for post-transplant monitoring of donor specific antibodies. The assay detects anti HLA IgG single antigen molecules which can be utilised for virtual crossmatch against the donor. The presence of such antibodies may lead to hyper-acute, acute or chronic antibody mediated rejection for multi-organ transplantation. The single antigen bead test is the most sensitive and specific solid phase test for identifying HLA antibodies in patient serum against individual antigen for class I.