Adjustment made to CPRA calculation for certain candidates

Published on: Thursday, December 7, 2023

Effective Dec. 6, 2023, the Calculated Panel Reactive Antibody (CPRA) calculation within the OPTN computer system was adjusted for transplant candidates with certain HLA antigens listed, in order to align with OPTN Policy 4.6. Under the previous CPRA calculation, a number of candidates with any of the 13 DQA1 unacceptable antigens listed in Table 4-3 were given a score that was determined to be between 0.0001% and 25.8% lower than their current scores, with a median of 5.59% lower.

At the time the discrepancy was discovered, 2,006 current transplant candidates had erroneously received a lower CPRA score, meaning their immune sensitivity was underestimated. Of those candidates who had their scores adjusted, 25 were reclassified as highly sensitized per OPTN Policy 8.4.F, making them eligible for additional allocation priority.

Background

The calculation was interpreting the unacceptable antigens as individual CPRA score values for each listed allele, when it should have given a combined value for alleles grouped together in the table. This only impacts candidate CPRA scores and does not change unacceptable antigen screening or HLA matching on the match run.

Patients can learn more about CPRA here.