18 A one-year retrospective review of virtual crossmatches performed for deceased-donor kidney offers

For every available deceased-donor kidney (DDK), the United Network for Organ Sharing generates a “match run” list, where eligible recipient candidates receive a sequence number (seqNo.) by order of priority. As part of the process to evaluate an organ offer, HLA physicians are consulted to perform a virtual crossmatch (VXM) to assess immune compatibility between donor and recipient. In this study, we aim to establish the rate of DDK transplantation for the VXMs performed at our institution and identify areas of improvement to ensure that VXMs are appropriately ordered. We queried our institutional electronic health records to retrieve a list of DDK VXMs performed in 2024. We recorded donor specific antibody (DSA) status, candidate calculated panel reactive antibody (cPRA) at the time of offer, and whether the transplant occurred. Additional data included seqNo. for each offer and explanations for declined offers. We used the independent student t-test to compare various averages between transplanted and non-transplanted groups, and the Chi-squared test to evaluate the association between DSA presence and transplant occurrence. In total, 1333 VXMs were performed for 485 different candidates, of which 266/485 (54.8%) were transplanted. The average number of VXMs per recipient was 3.0 in the transplanted group and 2.5 in the non-transplanted group (p = 0.006). Of the 1333 recipient:donor pairs, 266 proceeded to transplant (266/1333; 20.0%). Average cPRA was 36.6% in the transplanted group and 38.6% in the non-transplanted group (p = 0.254). DSAs were reported for 38/266 recipient:donor pairs in the transplanted group and 255/1067 in the non-transplanted group. Pairs without DSA were 1.9 times as likely to be transplanted (p < 0.001). The seqNo. was available for 1204/1333 recipient:donor pairs. The average seqNo. was 144.7 in the transplanted group, surprisingly higher than the non-transplanted group at 38.5 (p = 0.002). Finally, reasons for offer refusal were available for 546 of the 1067 recipient:donor pairs. Most refusals (86.8%) were non-DSA related. They included donor specific reasons (age, medical history, biopsy results, length of ischemia time, etc) and candidate specific reasons (unavailable, candidate refusal, temporarily medically unsuitable for transplant, etc), among others. Considering that only 13.2% of refusal reasons were related to DSA, we wonder whether VXMs are always required at the very initial steps of an offer evaluation and whether the VXM is overutilized in offers that are unlikely to lead to transplant. Each VXM is a billable consultation that requires at least 10 minutes of HLA physician time, which translates to 13,330 minutes or 222 hours in 2024 for DDK VXMs. Future directions include a collaboration with the transplant group to better understand their screening process to order VXM consultations and to identify possible areas of improvement.