Abstract
A
and A
B are rare phenotypes of the ABO blood group system. Some individuals with A
and A
B may have anti-A
antibodies that may be clinically significant or insignificant. The aim of this study was to determine the frequency of A
, A
B phenotypes and anti-A
antibodies in blood donors in Jazan, Saudi Arabia. This study also evaluated the reactivity potential of anti-A
antibodies.
Blood samples collected from 446 blood donors were typed for ABO (cell and serum grouping) and Rh D. Individuals with blood group A and AB were further subtyped by testing with anti-A
lectin. In addition to the serum grouping using A
red cells, A
and A
B individuals were screened for the presence of anti-A
in their sera against A
red cells at 4°C, 22°C and 37°C to determine the thermal amplitude of the reacting anti-A
antibody (if present).
Among A and AB, A
was the commonest phenotype (20.2%, n=90 out of 446) while A
B was found to be 1.8% (n=8) among AB phenotype. A
and A
B were found to be 2.2% (n=10) and 0.9% (n=4), respectively. Only one individual with A
B blood type showed cold reactive anti-A
antibody, the strength of which was 32.
A
and A
B were the rarest among ABO phenotypes in the studied population. Although rare, anti-A
antibody is not so uncommon. Care shall be taken during routine ABO grouping especially in cases of mix-field or weak positive reactions in A and AB phenotypes.