Eurotransplant Reference Laboratory
Information about Virtual PRA Calculator
Virtual PRA Calculator.
Virtual PRA is an application to be used by professionals working in HLA Laboratories and other HLA specialists to define the % Panel Reactive Antibodies (PRA) within the Eurotransplant donor population.
The virtual PRA is calculated on basis of unacceptable antigens only. These antigens are defined by HLA antibody analysis from screenings for HLA specific, relevant antibodies. The calculation is performed for unacceptable antigens on HLA-A, -B, -C, -DR and -DQ.

Description of the underlying database.
Calculations are performed on HLA data of deceased donors used for renal transplantation between 2010-2014 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 alleles 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 information.
The total number of datasets from donors in the database is 6870, with all loci being in Hardy-Weinberg Equilibrium on broad level.
All alleles are available at split level, except B14, Cw3 and DQ3. Bw4 and Bw6 are included in the database. In case of missing data, Bw4/Bw6 has been assigned based on B-antigens.
Please be aware that assigning a Bw4 will not include corresponding HLA-A antigens. HLA-A antigens harbouring a Bw4 epitope need to be filled in separately.
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.

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