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, acceptable and unacceptable antigens. Allocation within the AM program is based on ABO ET-compatibility. Only HLA-A, -B and -DR on the split antigen level are used for acceptable antigens in combination with the patient’s own HLA typing. Please be aware that broad antigens for patient’s typing are ignored. Entering a broad antigen as acceptable means that all underlying splits are regarded as acceptable. 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 one HLA-DR broad antigen with the patient’s HLA-DR broad antigen, excluding donors with one or more unacceptable antigens.
The program first excludes donors based on unacceptable antigens. In the next step the program matches the donors based on the patients typing, acceptables and blood group.
So it is possible to enter A*01:01 as unacceptable and A1 as accaptable. In that case all donors with alleles A1 other than A*01:01 are included in the frequency.

Description of the underlying database.
Calculations are performed on the ETRL reference database v4.0, which contains HLA data of 10.000 individuals from within the Eurotransplant area, obtained from genotype frequencies provided by the DKMS.
Full 11-locus genotype frequencies with alleles at p-group level of registered stem cell donors were used from all eight Eurotransplant countries. HLA types for 11 loci on second field level were constructed on a country-specific basis in equal numbers to the ETRL reference database v3.0. Bw4/Bw6 were 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. DR53 has been removed for individuals with DR7 and DQ9, because in this case DR53 is non-expressed.
The original distribution of blood groups for a specific country in ETRL reference database 3.0 was randomized and assigned to individuals of panel 4.0 of the same country.
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