Introduction: Virtual crossmatch (vXM) started in all member-states of Eurotransplant (ET) on 2023-01-23. This required changes: Due to ambiguity laboratories upload all possible HLA-alleles identified in a donor (A, B, C, DRB1, DRB3, DRB4, DRB5, DQB1, DQA1, DPB1, DPA1) as HML file to ET. ET converts this into 2-field-typing respecting CIWD 3.0 catalogue and 18th HLA nomenclature workshop. Laboratories check correctness and adjust only unexpected deviations in phenotypes. Hereafter all kidney, pancreas and intestine waiting list candidates with unacceptable antigens or alleles against the donor are deselected from further allocation procedure in this donor. This vXM is complemented by physical crossmatch (LCT) prospectively for immunized recipients prospectively  and retrospectively for all other recipients.
Methods: (1) review of HLA-HML-File uploads until 2024-3-25 for technical limitations in Germany. (2) review of LCT performed from 2023-4-24 to 2024-03-25 under vXM-rules exclusively in place in Germany
Results: (1) In total HML-Files of 1173 donors were uploaded. 91% of the cases required no major manual correction and 8% of the cases needed manual adjustment for complex HLA-issues. Switch backt to manual backup occurred in 1% (13 cases). Mean duration for completing vXM was 6 minutes including all manual work. (2) A total of 1468 LCT-test were performed for recipients with negative result and 13 positive results occurred in kidney recipients allocated initially (5 due to autoimmune disease, 1 due to DP/DQA-Ab not entered, 1 due to decision of recipient centre, 1 due to IT-issue ET, 1 due to immunization not reported, 1 due to EBV infect, 1 due to non-HLA-Ab, 1 due to unexplainable event not related to HLA, 1 due to possible overlap of HLA-epitopes with B-cell test failure not allowing conclusive interpretation).
Conclusion: Since implementation of vXM quality of donor HLA-typing improved and is standardized. For LCT an excellent prediction of results exists by vXM. Further quality control is necessary for discussion about future LCT indication.