NOTE: This information solely addresses OPTN requirements for pre-transplant crossmatches and does not represent any change in OPTN policy. CMS regulation 42 CFR 493.1278(f)(2) addresses additional crossmatch requirements. The information below is not meant to apply to any CMS requirements or any ongoing discussion of how to interpret CMS regulation.
OPTN Policy 4.6 lists the requirements for histocompatibility laboratories to perform a pre-transplant final crossmatch for all transplants involving a kidney (including multi-organ transplants) and to report the results to the transplant program prior to transplantation. OPTN Policy 13.10 also requires a final pre-transplant crossmatch for transplant centers intending to perform a kidney paired donation transplant. Additionally, the specifications for the crossmatch and reporting of results must be delineated in the written agreement between the histocompatibility laboratory and the transplant program(s) it supports, as stated in Bylaw Appendix C.2.
OPTN Policy 4.10 provides reference tables of equivalences for HLA antigens and alleles. The UNetSM match system uses the tables for a variety of purposes. These purposes include, but are not limited to, determining candidate priority for allocation of a zero-ABDR mismatched graft; assessing DR mismatch point assignments; and preventing incompatible candidates from appearing on match runs via listing of unacceptable/avoid antigens. However, please note:
- The match system does not fulfill the requirement for performing a pre-transplant final crossmatch. UNetSM is neither designed for, nor intended to predict whether an individual organ offer will result in an acceptable transplant. It is recommended that the final determination of immunologic compatibility be made by the transplant program in conjunction with its histocompatibility laboratory director. The individual histocompatibility laboratory is still responsible for performing a pre-transplant final crossmatch as specified in Policy 4.6 and in accordance with the written agreement for the transplant program(s) it supports.
- While the equivalency tables are reviewed and updated on a regular basis, they may not address additional clinically significant findings that may impact the decision to transplant/not transplant a particular candidate. Moreover, the tables cannot account for any recent advances in the field of histocompatibility that may impact a transplant decision.
