Optimum Conditions for the Preparation of Red Blood Cell Suspensions for ABO Antibody Titration

ABSTRACT

BACKGROUND: There is significant inter-laboratory variation in the ABO antibody (Ab) titer levels of blood samples because a standardized method has not yet been developed. The aim of this study was to identify the best conditions for the preparation of the red blood cell (RBC) suspensions so as to aid the development of a standard ABO Ab titration method. METHODS: Serum samples from apparently healthy adults and RBCs from three different sources (residual EDTA blood from healthy adults, donor blood in citrate-phosphate-dextrose-adenine-1 [CPDA-1], and a commercially available RBC reagent) were used for Ab titrations. We measured the titers for each blood group under various conditions, including the time period of storage (days), the ratio of serum to RBC volume, and the RBC sources. The techniques for room temperature incubation and the indirect antiglobulin test were used for the tube and the gel card test. RESULTS: A storage period of 6 to 7 days significantly affected the Ab titers. Samples with 3% RBCs in a 11 serum to RBC volume ratio had significantly lower Ab titers than those with 2% RBCs in a 11 ratio or those with 3% RBCs in a 21 ratio. There were no significant differences in the Ab titers of RBCs from different sources. CONCLUSIONS: To reduce inter-laboratory variations in ABO Ab titrations, using RBC suspension within five days of storage and applying ratio of serum to RBC volume to 21 with 3% RBC in the tube test will be helpful when using home-made RBC suspension.