Management Through the National Kidney Registry (NKR)
Management through the NKR does not change the fundamental requirements for medical evaluation and compatibility testing—the recipient center must independently perform all critical immunologic testing regardless of remote donor approval. 1
Core Compatibility Testing Requirements Remain Unchanged
Mandatory Crossmatch Testing at Recipient Center
- A recipient-donor crossmatch must be performed at the recipient's center using flow cytometry or enhanced complement-dependent cytotoxicity (CDC) assay to detect IgG antibodies against donor HLA antigens, even if the donor was approved remotely through NKR. 1
- Enhanced methods (AHG-CDC or flow cytometry) are required rather than standard NIH-CDC crossmatching alone, as these more sensitive assays detect clinically relevant antibodies that could cause rejection. 2, 1
- Multiple recipient sera must be tested including historically reactive sera, current sera, and immediately pre-transplant sera to identify immune memory that could trigger accelerated rejection. 2, 1
- A positive crossmatch with IgG antibodies to HLA antigens on either T cell or B cell targets is an absolute contraindication to transplantation. 2, 1
Complete HLA Typing and Antibody Assessment
- Full HLA typing for MHC Class I (A, B, C) and Class II (DP, DQ, DR) must be performed on both donor and recipient, with assessment of donor-specific anti-HLA antibodies in the recipient. 2, 1
- Highly sensitized recipients require particular scrutiny as they may have antibodies detectable only by more sensitive methods like flow cytometry. 1
- The flow cytometry crossmatch is more sensitive than AHG-CDC crossmatch, and each transplant center must decide how to interpret AHG-negative, flow cytometry-positive results based on their own clinical data. 2
ABO Blood Type Verification
- Independent ABO blood typing must be confirmed at the recipient's center, performed twice before donation to prevent incompatible transplantation, even if performed remotely. 2, 1
- Blood group A subtype testing should be performed when the recipient has anti-A antibodies. 2, 1
Recipient-Specific Suitability Assessment
Medical Appropriateness Evaluation
- The recipient's center must independently evaluate whether the donor kidney is medically suitable for their specific recipient, considering donor kidney quality, vascular anatomy, and recipient surgical risk. 1
- While specialists may "clear" a donor for surgery, the recipient's transplant team must independently determine if this represents acceptable risk for their specific recipient, as this is an optional procedure. 2, 1
Incompatibility Management Planning
- If ABO or crossmatch incompatibility exists, the recipient's center must have an effective incompatibility management strategy in place before proceeding. 2, 1
- Recipients must be counseled about center-specific outcomes for incompatible transplantation, as these vary based on institutional expertise. 2, 1
- Donor candidates who are ABO or HLA incompatible should be informed of kidney paired donation availability, risks, and benefits. 2
Critical Pitfalls to Avoid
Do Not Assume Compatibility Based on Remote Approval
- Never assume immunologic compatibility based solely on NKR or remote center approval—independent crossmatch testing at the recipient center is mandatory. 1
- Do not rely on standard NIH-CDC crossmatching alone; enhanced methods are required to detect clinically relevant antibodies. 2, 1
Do Not Ignore Historical Immune Reactivity
- Testing only current sera may miss immune memory that causes accelerated rejection—historically reactive sera must be included. 2, 1
- IgM-positive crossmatches should be distinguished from clinically relevant IgG reactivity through heat or chemical treatment, as IgM antibodies are not contraindications to transplantation. 2, 1