Comparative Evaluation of Titer Estimation of ABO Isoagglutinins using Three Different Methods

Abstract

Background and Aims: While automation has the advantage of objectivity, ease of use, and reproducibility with well-defined end points of agglutination reaction, standardization of these methods has still not been possible. The aim of the present study was to compare results obtained by manual conventional test tube technique (CTT) with semi-automated, column agglutination technique (CAT), and fully automated hemagglutination/solid-phase red cell adherence (HA/SPRCA) by calculating and comparing correlation and median immunoglobulin M (IgM) and immunoglobulin G (IgG) titer. Materials and Methods: This was a prospective, observational study conducted from October 2019 to March 2020. All consecutive A, B, and O group donors who consented to participate were included in the study. All samples were consecutively tested by CTT, CAT, and HA/SPRCA. Results: A total of 300 (100 each from A, B, and O blood groups) donors were included. IgG titers were higher than IgM titers in most group O individuals. This difference was more evident with the use of CAT. The correlation between CTT and CAT was found to be strong, whereas the correlation between CTT and HA/SPRCA was found to be variable for anti-A and anti-B IgG and IgM titers. When measured by CTT and CAT, median anti-A and anti-B titer results for group O individuals were similar. Anti-A and anti-B median titer results obtained by CTT and CAT for group A and B individuals were also similar. Conclusion: Semi-automated method (CAT) shows higher ability in detecting ABO isoagglutinins than the manual method (CTT) and automated method (HA/SPRCA). These methods cannot be used interchangeably.