Comparative Evaluation of Five Different Methods of Anti-ABO Antibody Titration: An Aid for ABO-Incompatible Organ Transplants.

The accurate estimation of ABO antibody titers is of the utmost importance in organ transplants involving ABO incompatibility. We aim to compare five different methods of titration and analyze the data. Samples of 48 O group blood donors who donated during the month of December 2015 to January 2016 in our institution were subjected to ABO antibody titration by five different methods: immediate spin (IS) tube titer, antihuman globulin phase tube titer, Coomb's gel card titer, gel card titer after dithiotreitol (DTT) treatment of plasma, and the solid phase red cell adherence method. The mean number of titer serial dilution steps in the different titer estimation methods was compared using the paired t-test and McNemar test. A correlation between the methods was tested using Spearman's rho and kappa statistics. The median antiglobulin (AHG) phase tube titers were found to be the highest anti-A (128) and anti-B (192) titers. Significant differences in the ABO antibody titer readings among the five different methods were noted. Titers were reduced by DTT treatment in nearly 50% samples tested for both anti-A and anti-B titers. Average agreements between the DTT-applied AHG phase gel card titers and the solid phase red cell adherence (SPRCA) titers was observed for anti-A (κ = 0.473) and anti-B (κ = 0.530). The AHG phase tube and gel cards titers showed poor agreements. There are differences in the interpretability of the ABO antibody titer among different techniques. Consistent and uniform application of the method for titration throughout the treatment of a patient is highly essential.