**6. Conclusion**

Understanding of the transplantation antigens and crossmatching is a vital tool in transplant. Crossmatching plays a key role in assessing immune compatibility between a donor and recipient. A positive T-cell CDC crossmatch would usually mean that a particular pairing should not proceed. But in some cases, a desensitization protocol may allow such a transplant to occur, avoiding hyperacute or early acute rejection. However they have inferior longterm graft outcomes compared with patients who are not sensitized to their donor. The advent of flow crossmatching and Luminex assays has allowed the detection of very lower titre, anti-HLA antibodies of uncertain clinical significance.

CDC crossmatching along with Luminex should be used in determining anti-HLA antibodies. The role of flow crossmatching is less clear and its help in decision making is unclear. The ideal future crossmatch will be highly sensitive in identifying DSA and provide accurate prediction of the functional significance of the antibody. This will hopefully allow differentiation between transplants that can safely proceed in the face of a clinically irrelevant DSA while providing clear prognostic information in the setting of more serious antibodies.

Further studies are required to better define the significance of very low-level DSA, non‐ complement fixing antibodies, IgM antibodies and non-HLA antibodies as well as the importance of assessing T cellular sensitization.
