Evaluation of different methods for antibody titre determination in ABO-incompatible kidney transplantation

Blood type antibody-mediated rejection is considered the main obstacle to ABO blood type-incompatible kidney transplantation. Choosing an appropriate antibody-level determining method and setting a rational baseline are critical for safely conducting ABO-incompatible kidney allografts. However, due to the differences in antibody detection methods between laboratories, there is no unified baseline to confirm the true titer. Therefore, a generally applicable method must be selected to determine the level of anti-ABO antibodies before surgery, and the actual critical titer level should be set accordingly. This study aims to guide the selection of appropriate antibody titer detection methods for ABO-incompatible kidney transplant recipients by comparing the differences in titer results obtained through various detection methods.

A total of 210 ethylene diamine tetraacetic acid (EDTA)-anticoagulated samples were obtained from patients before or after ABO-I kidney transplantation in our centre. In this study, we tested immunoglobulin M (IgM) and immunoglobulin G (IgG) ABO antibody titres using different detection methods, i.e., a tube test (TT), a microcolumn gel card test (MGT), and a glass bead card test (GBT), to evaluate deviations in antibody levels.

According to our results, the IgM titre presented by the TT varied less than one standard dilution from that of the MGT; while the TT resulted in a 2 to 4 titre deviation from that determined by the GBT. For IgG, the titres obtained by the MGT were always one standard dilution higher than those obtained by the TT, and the TT-based and GBT-based titres differed by 2-3 serial dilution steps.

It is important that clinical laboratories employ a consistent method of sample testing for a particular patient, and indicate the approach used when reporting results. A further clinical retrospective study revealed that the MGT could effectively monitor titre changes following surgery.