In recent years there have been major advances in the technology for the detection and definition of human leukocyte antigen antibodies. In this overview we describe the evolution in laboratory technology, the techniques currently available and consider their application in antibody specificity definition and in understanding a patient's sensitization profile. We discuss the importance of antibody specificity definition in facilitating efficient national organ allocation and informing clinical discussion regarding the appropriate pathway for sensitized patients awaiting renal transplantation.