Recognizing and resolving ABO discrepancies

Abstract

Patient samples are routinely typed for ABO prior to transfusion. Determining the ABO group requires both red blood cell (RBC) antigen typing for A and B (forward type) and testing for anti-A and anti-B in the plasma (reverse type). An ABO discrepancy exists when the result of an ABO RBC typing, or forward type, does not agree with the result of the plasma typing, or reverse type. This brief review examines several causes of ABO discrepancies encountered in the clinical transfusion service. Options for resolving these discrepancies are presented, including a discussion of which discrepancies should be resolved using molecular testing. Finally, case studies illustrate transfusion options in patients with ABO discrepancies. Discrepancies can also be encountered when ABO typing is performed on samples from blood or tissue donors, although those discrepancies will not be discussed in this review. Immunohematology 2017;33:76-81.

Analysis of Blood Group Discrepancy in Healthy Blood Donors at a Tertiary Care Referral Hospital from Eastern India: A Retrospective Study

“…Type I discrepancy characterizes by a diminished reaction in reverse grouping due to missing or weak antibodies. 9 11 Out of six cases, four donor samples had blood group discrepancy due to weak B antibodies, and the rest two samples had both anti-A and anti-B antibodies. The presence of weak B antibody is more common than the presence of anti-A antibody in type I ABO discrepancy.…”

“…Type II ABO discrepancy occurs because of an unpredicted reaction in cell grouping owing to diminished expression of the red cell antigens. 9 11 A weak subgroup of A is more common than a weak subgroup of B. Subgroups of A weaker than A2 contribute to almost 1% of ABO blood group discrepancy. 3 The subgroup of A can be broadly divided into two categories depending on the agglutination of red cells with anti-A.…”

“…Type IV discrepancy is usually attributed to the presence of cold reactive alloantibodies or cold reactive isoantibodies or cold reactive autoantibodies present in the serum of the donor or patient sample. 6 9 Out of eight cases, three donors had naturally occurring irregular antibody with the specificity of anti-M and three donors had antibody specificity of anti-Le b as they were reactive with O cells at room temperature. However, the thermal amplitude of these two antibodies extended up to 37°C degrees and was therefore clinically significant.…”

ABO Blood System and COVID-19 Susceptibility: Anti-A and Anti-B Antibodies Are the Key Points

“…Indeed, patients with the O blood group with low anti-A antibodies were not inhibitory in the host cell adhesion assay ( 24 ). The lack of or drop in antibodies due to any immunosuppressive situation creates ABO discrepancies ( 56 ). Therefore, it is of value to determine whether the ABO group performed both forward (red blood cell antigen) and reverse (anti-A and anti-B antibodies in plasma).…”

Identification of a novel A allele with a c.977A>C variation on the ABO*A1.02 allele

“…Currently, it needs to perform compatibility for ABO blood group in clinical blood transfusion. 1 The ABO gene consists of seven coding exons, which encode one of two different glycosyltransferases to form A or B antigens respectively. 2 There are only four antigens in the ABO blood group system, but any polymorphism or variation that changes the activity or specificity of the glycosyltransferases will be altered the ABO phenotype.…”