cPRArgentina: a population-specific cPRA calculator incorporating optional ABO compatibility

Calculated panel reactive antibody (cPRA) is used to assess the proportion of donors expected to be incompatible with a transplant candidate based on unacceptable Human Leukocyte Antigen (HLA) specificities. Its accuracy depends on how well the reference donor population reflects the actual donor pool and on the compatibility criteria considered. We developed cPRArgentina, a web-based application that directly compares patient-specific unacceptable HLA antigens with deceased donor data from Argentina and can optionally incorporate ABO compatibility. We evaluated the application using 100 synthetic recipient profiles covering different levels of HLA sensitization and all ABO blood groups. Incorporating ABO compatibility increased cPRA in all blood groups except AB, with the greatest increases observed in groups O and B. Its effect was also greater among profiles with lower HLA-only cPRA and decreased as HLA sensitization increased. These findings show how incorporating ABO compatibility can change the picture of donor availability beyond HLA sensitization alone. cPRArgentina provides a population-specific approach to cPRA calculation using Argentine donor data, with a flexible design that can incorporate broader donor data and additional HLA information as they become available.