ABO CERTIFICATION STUDY GUIDE 2026
COMPLETE QUESTIONS AND SOLUTIONS
VERIFIED A+
● What can occur if an incompatible ABO type is transfused? Answer:
Immediate lysis of donor red blood cells, which may be fatal.
● When was the ABO blood group discovered? Answer: In 1900.
● What type of inheritance do ABO blood groups exhibit? Answer:
Codominant alleles with a silent allele for O (no product).
● What are isoagglutinins? Answer: Anti-A or anti-B antibodies
detected in the plasma of individuals.
● What is the relationship between forward and reverse grouping in
ABO testing? Answer: There is an inverse reciprocal relationship; both
must confirm and resolve any discrepancies.
● What type of antibodies are predominantly found in ABO antibodies?
Answer: IgM antibodies.
, ● What is the role of FDA licensed antisera in ABO typing? Answer:
They are standardized reagents used to identify blood types through
agglutination reactions.
● What is the expected result of ABO front typing with anti-A and anti-
B? Answer: 0, 0 for O; +, 0 for A; 0, + for B; +, + for AB.
● What is the Bombay phenotype? Answer: A condition where RBCs
lack normal ABH antigens due to a double dose of the h gene, inherited
as an autosomal recessive trait.
● What are weak A subgroups? Answer: Phenotypes that show weaker
variable serological reactivity with commonly used anti-A reagents.
● What are the two types of precursor chains in ABH antigen
formation? Answer: Type I and Type II precursor chains, differing only
in linkage.
● What is the primary product of the A allele in ABO blood group
genes? Answer: A-specific glycosyltransferase that produces A antigen.
● What is the significance of the H antigen in the ABO blood group
system? Answer: It is a precursor for ABH antigen formation and is
produced by the H-specific fucosyltransferase.
COMPLETE QUESTIONS AND SOLUTIONS
VERIFIED A+
● What can occur if an incompatible ABO type is transfused? Answer:
Immediate lysis of donor red blood cells, which may be fatal.
● When was the ABO blood group discovered? Answer: In 1900.
● What type of inheritance do ABO blood groups exhibit? Answer:
Codominant alleles with a silent allele for O (no product).
● What are isoagglutinins? Answer: Anti-A or anti-B antibodies
detected in the plasma of individuals.
● What is the relationship between forward and reverse grouping in
ABO testing? Answer: There is an inverse reciprocal relationship; both
must confirm and resolve any discrepancies.
● What type of antibodies are predominantly found in ABO antibodies?
Answer: IgM antibodies.
, ● What is the role of FDA licensed antisera in ABO typing? Answer:
They are standardized reagents used to identify blood types through
agglutination reactions.
● What is the expected result of ABO front typing with anti-A and anti-
B? Answer: 0, 0 for O; +, 0 for A; 0, + for B; +, + for AB.
● What is the Bombay phenotype? Answer: A condition where RBCs
lack normal ABH antigens due to a double dose of the h gene, inherited
as an autosomal recessive trait.
● What are weak A subgroups? Answer: Phenotypes that show weaker
variable serological reactivity with commonly used anti-A reagents.
● What are the two types of precursor chains in ABH antigen
formation? Answer: Type I and Type II precursor chains, differing only
in linkage.
● What is the primary product of the A allele in ABO blood group
genes? Answer: A-specific glycosyltransferase that produces A antigen.
● What is the significance of the H antigen in the ABO blood group
system? Answer: It is a precursor for ABH antigen formation and is
produced by the H-specific fucosyltransferase.
