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Author Notes:

James H. Lan, Vancouver Coastal Health Research Institute, Vancouver, Canada. Email: james.lan@vch.ca

NIAID 1U01AI152960‐01 “MHC and KIR Sequencing and Association Analyses in the iGeneTRAiN Studies.” This work was made possible by a Scholarly Retreat at Tulane's A Studio in the Woods. JHL is supported by a Michael Smith Foundation for Health Scholar award. MK is supported by a Michael Smith Health Professional Investigator award. This analysis was based on OPTN data as of March 13, 2022. This work was supported in part by Health Resources and Services Administration contract HHSH250‐2019‐00001C. The content is the responsibility of the authors alone and does not necessarily reflect the views or policies of the Department of Health and Human Services nor does mention of trade names, commercial products, or organizations imply endorsement by the US Government.

The authors of this manuscript have conflicts of interest to disclose as described by the American Journal of Transplantation. Dr. Gragert was supported by an OPTN subcontract for “Update CPRA Calculator.”



  • Science & Technology
  • Life Sciences & Biomedicine
  • Surgery
  • Transplantation
  • ABO incompatibility
  • ethics and public policy
  • genetics
  • histocompatibility
  • immunogenetics
  • organ allocation
  • organ procurement and allocation
  • panel reactive antibody (PRA)
  • registry/registry analysis
  • translational research/science

ABO-adjusted calculated panel reactive antibody (cPRA): A unified metric for immunologic compatibility in kidney transplantation


Journal Title:



Volume 22, Number 12


, Pages 3093-3100

Type of Work:

Article | Final Publisher PDF


Implementation of the kidney allocation system in 2014 greatly reduced access disparity due to human leukocyte antigen (HLA) sensitization. To address persistent disparity related to candidate ABO blood groups, herein we propose a novel metric termed “ABO-adjusted cPRA,” which simultaneously considers the impact of candidate HLA and ABO sensitization on the same scale. An ethnic-weighted ABO-adjusted cPRA value was computed for 190 467 candidates on the kidney waitlist by combining candidate's conventional HLA cPRA with the remaining fraction of HLA-compatible donors that are ABO-incompatible. Consideration of ABO sensitization resulted in higher ABO-adjusted cPRA relative to conventional cPRA by HLA alone, except for AB candidates since they are not ABO-sensitized. Within cPRA Point Group = 99%, 43% of the candidates moved up to ABO-adjusted cPRA Point Group = 100%, though this proportion varied substantially by candidate blood group. Nearly all O and most B candidates would have elevated ABO-adjusted cPRA values above this policy threshold for allocation priority, but relatively few A candidates displayed this shift. Overall, ABO-adjusted cPRA more accurately measures the proportion of immune-compatible donors compared with conventional HLA cPRA, especially for highly sensitized candidates. Implementation of this novel metric could enable the development of allocation policies permitting more ABO-compatible transplants without compromising equity.

Copyright information:

© 2022 The Authors. American Journal of Transplantation published by Wiley Periodicals LLC on behalf of The American Society of Transplantation and the American Society of Transplant Surgeons.

This is an Open Access work distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (https://creativecommons.org/licenses/by-nc-nd/4.0/).
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