Eurotransplant Reference Laboratory
Information about Donor Frequency Calculator Acceptable Mismatch program.
Donor Frequency Calculator AM Program
Donor Frequency Calculator AM Program is an application to be used by professionals working in HLA Laboratories and other HLA specialists to determine the chance of a highly sensitized patient to receive an offer of a compatible renal transplant when included in the Eurotransplant Acceptable Mismatch (AM) program.
The program is based on the patient’s HLA type, blood group, and acceptable antigens. Allocation within the AM program is based on ABO ET-compatibility. Only HLA-A, -B and -DR are used for acceptable antigens in combination with the patient’s own HLA typing. Broad antigens for patient’s typing are ignored, except B14. In addition, Bw4/Bw6 cannot be entered into the patient typing field. Entering a broad antigen as acceptable means that all underlying splits are regarded as acceptable. The HLA-A, -B and -DR typing information must consist of two antigens per locus. For homozygous antigens the antigen must be entered in duplicate. The percentage given is the chance of finding a compatible donor organ based on the patient’s own HLA type with the addition of acceptable antigens. The calculator takes into account the minimal match criteria of sharing of one HLA-B antigen and one HLA-DR antigen, or two HLA-DR antigens with the patient’s own HLA antigens.


Description of the underlying database.
Calculations are performed on the ETRL reference database v3.0, which contains HLA data of 10.000 deceased donors used for renal transplantation between 2012 and 2018 within the Eurotransplant area.
Donors with complete HLA typing for HLA-A, -B, -C, -DR and -DQ have been selected. Donors with missing HLA data for one or more loci were excluded after verification that the HLA antigens that were known from these donors were not significantly different from the HLA antigens of donors with complete HLA typing information.
All alleles are available at split antigen level, except B14 and Cw3. Bw4 and Bw6 are included in the database. In case of missing data, Bw4/Bw6 has been assigned based on HLA-B antigens only.
Please be aware that assigning a Bw4 will not include corresponding HLA-A antigens. HLA-A antigens harboring a Bw4 epitope need to be filled in separately.
Missing split alleles for HLA-DQ3 were imputed by using linkage information of HLA-DRB1.
Finally, DR51/52/53 are also included in the database. In case of missing data, imputation based on DRB1 typing was performed. DR53 has been removed for donors with DR7 and DQ9, because in this case DR53 is non-expressed.


For any suggestion or remarks, please contact:
etrl@eurotransplant.org