Table 1.
Technological advantages | Technological limitations |
Qualitative: enables precise identification of all antibody specificities in complex sera (DSA) | Some positive results can be caused by antibodies to denatured HLA |
Comprehensive: distinguishes antibodies to all common alleles for HLA-A, HLA-B, HLA-C, HLA-DRB1, HLA-DRB3/4/5, HLA-DQA1, HLA-DQB1, HLA-DPA1, HLA-DPB1 | Occasional high background binding requiring repeat testing and absorption protocols |
Semiquantitative: enables determination of antibody levels (high, intermediate, and low) | Variable HLA protein density on beads. Blocking factors may cause false-negative or misleading low assessment of antibody levels (prozone?); IgM and C1 can block IgG binding |
Sensitive: enables detection of weak antibody testing | |
Rapid: enables real-time antibody monitoring for DSA. Pre- transplantation and post-transplantation antibody monitoring (assist diagnosis of ABMR). Virtual XM | Lot-to-lot variation requiring validation. Vendor-specific variation |
Enables detection of non-HLA-specific antibodies (e.g., MICA) | |
Detection and differentiation between immunoglobulin class and isotype (e.g., complement fixing and non-complement fixing C4d and C1q | Reagents not standardized |
ABMR: Antibody mediated rejection; DSA: Donor specific HLA antibodies; HLA: Human leukocyte antigens; MICA: Major histocompatibility complex class I-related chain A; SAB: Single-antigen beads; XM: Cross-match.