This is an important pre-transplant immunological study indicated in the organ transplantation process. This study evaluates immune reactions against human leukocyte antigens (HLA) by screening antibodies against Class I (HLA-A, -B, -C) and Class II (HLA-DR, -DP, -DQ) in the recipient’s body using solid base platforms, or Luminex bead assays. A positive result indicates pre-existing antibodies causing a risk of transplant rejection.