Table 1.

Special allocation programs for the highly sensitized.

	Highly Sensitized Definition	Strategies to Increase Transplantation in the Highly Sensitized	Consequences
KAS (2014)	cPRA ≥ 98%	Sliding scale with extra points from cPRA ≥ 20% Local (cPRA 98%), regional (cPRA 99%) or national (cPRA 100% allocation	Decrease in waiting times, increased rate of highly sensitized patients getting transplants Higher long-ischemia times and more HLA mismatches.
Eurotransplant Acceptable mismatch program (1989)	cPRA ≥ 85% (Include only HLA antibodies explained by sensitizing events)	Increase the recipient HLA antigen phenotype Multi-country allocation	Decrease in waiting times, 80% rate of highly sensitized patients getting transplants, similar acute rejection and graft outcomes than non-sensitized
Scandiatransplant Acceptable mismatch program (2020)	cPRA ≥ 80%	Multi-country allocation Acceptable mismatch program (2009) for patients with a transplantability score ≤ 2%; Prioritization for the highly sensitized	Significant increase of transplant rates in the highly sensitized
UK allocation program (2019)	cRF > 85%	National allocation Top priority (tier A) if cRF ≥ 85%, 10% patients most difficult to match, ≥7 years on the waiting list	Reduction of 50% on the patients waiting for more than 5 years;
Spain PATHI (2015)	cPRA ≥ 98%	National priority allocation program based on virtual cross-match	10–30-fold increase in the chances of finding a donor Significantly increase of transplantability rate
France Authorized Antigen Program	cPRA ≥ 85% or cPRA > 70% at transplant	National priority to the higly sensitized Authorized antigen program + age matching	Highly sensitized with increased transplant rates

KAS—Kidney Allocation System OPTN; cPRA—calculated PRA; cRF—calculated reaction frequency.