ABO CERTIFICATION EVALUATION 2026
QUESTIONS WITH ANSWERS GRADED A+
◉ What are the four major blood groups in the ABO system? Answer: A,
B, AB, and O.
◉ What does Landsteiner's rule state about ABO antibodies? Answer:
Normal individuals possess ABO antibodies to antigens absent from
their red cells.
◉ At what age do ABO antibodies typically develop? Answer: ABO
antibodies develop by 3 to 6 months of age.
◉ What is the significance of the H gene in the ABO blood group
system? Answer: The H gene is essential for the expression of A and B
antigens on red blood cells.
◉ What are the differences between A1 and A2 subgroups? Answer: A1
has a higher antigen density than A2 and reacts differently with anti-A1
and anti-H lectins.
, ◉ What is the Bombay phenotype? Answer: A rare blood type where
individuals do not express H antigens due to a mutation in the H gene.
◉ What is the role of glycosyltransferases in the ABO blood group?
Answer: They add specific sugars to oligosaccharide chains, defining the
ABO antigens.
◉ What are the precursor substances for A, B, and H antigens? Answer:
Type 1 precursor oligosaccharides are for body fluids; Type 2 is for
RBCs.
◉ What is the relationship between ABO genotypes and phenotypes?
Answer: Genotypes determine the phenotypes expressed in blood types,
influenced by the presence of H antigens.
◉ What is the prevalence of blood groups in the general population?
Answer: The prevalence varies, with O being the most common and AB
the least common.
◉ What is the expected clinical significance of naturally occurring ABO
antibodies? Answer: They can cause transfusion reactions if
incompatible blood is transfused.
QUESTIONS WITH ANSWERS GRADED A+
◉ What are the four major blood groups in the ABO system? Answer: A,
B, AB, and O.
◉ What does Landsteiner's rule state about ABO antibodies? Answer:
Normal individuals possess ABO antibodies to antigens absent from
their red cells.
◉ At what age do ABO antibodies typically develop? Answer: ABO
antibodies develop by 3 to 6 months of age.
◉ What is the significance of the H gene in the ABO blood group
system? Answer: The H gene is essential for the expression of A and B
antigens on red blood cells.
◉ What are the differences between A1 and A2 subgroups? Answer: A1
has a higher antigen density than A2 and reacts differently with anti-A1
and anti-H lectins.
, ◉ What is the Bombay phenotype? Answer: A rare blood type where
individuals do not express H antigens due to a mutation in the H gene.
◉ What is the role of glycosyltransferases in the ABO blood group?
Answer: They add specific sugars to oligosaccharide chains, defining the
ABO antigens.
◉ What are the precursor substances for A, B, and H antigens? Answer:
Type 1 precursor oligosaccharides are for body fluids; Type 2 is for
RBCs.
◉ What is the relationship between ABO genotypes and phenotypes?
Answer: Genotypes determine the phenotypes expressed in blood types,
influenced by the presence of H antigens.
◉ What is the prevalence of blood groups in the general population?
Answer: The prevalence varies, with O being the most common and AB
the least common.
◉ What is the expected clinical significance of naturally occurring ABO
antibodies? Answer: They can cause transfusion reactions if
incompatible blood is transfused.
