Histocompatibility testing for highly sensitized transplant candidates.

HLA antibodies can develop for many different reasons and are often present in the serum of patients awaiting renal transplantation. These antibodies can limit the patient's ability to find a compatible donor and are a risk factor for poor graft outcome. Detection of HLA antibodies is important for identifying compatible donors, assessing the pretransplantation risk for rejection, and diagnosing humoral rejection posttransplantation. The results of antibody screens are also useful when interpreting crossmatch results. Assays used for detecting panel-reactive and donor-specific HLA antibodies, including cytotoxicity, flow cytometry, and solid phase assays, are described in this review.