ABO ADVANCED FORMULAS TEST
SCRIPT 2026 TEST PAPER
QUESTIONS AND SOLUTIONS
CERTIFICATION REVIEW GRADED
A+
◉ What organization created a standardized naming system for blood
groups in 1980? Answer: The International Society of Blood Transfusion
(ISBT).
◉ What are the two main blood group systems focused on in this
chapter? Answer: ABO and H blood group systems.
◉ Who discovered the ABO blood group system? Answer: Karl
Landsteiner in 1900.
◉ What are the three major groups identified in the ABO blood group
system? Answer: A, B, and O.
◉ What is Landsteiner's rule regarding ABO antibodies? Answer:
Normal healthy individuals possess ABO antibodies to the blood group
antigens absent from their cells.
◉ What can occur if incompatible blood types are transfused? Answer:
Acute hemolytic transfusion reactions.
, ◉ Where are ABO antigens widely distributed in the body? Answer: In
red blood cells, lymphocytes, platelets, and most epithelial and
endothelial cells.
◉ At what stage of development are ABO antigens detectable? Answer:
At 5-6 weeks in utero.
◉ What is the role of the H antigen in the ABO blood group system?
Answer: It is critical for the expression of A and B antigens.
◉ What chromosome is the H antigen found on? Answer: Chromosome
19.
◉ What is the dominant allele for the H antigen? Answer: H, with a
frequency greater than 99.99%.
◉ What enzyme does the H antigen gene code for? Answer: L-
Fucosyltransferase.
◉ How is the A antigen formed? Answer: By attaching N-
acetylgalactosamine to the third carbon of galactose on the H antigen.
◉ How is the B antigen formed? Answer: By attaching D-galactose to
the third carbon of galactose on the H antigen.
SCRIPT 2026 TEST PAPER
QUESTIONS AND SOLUTIONS
CERTIFICATION REVIEW GRADED
A+
◉ What organization created a standardized naming system for blood
groups in 1980? Answer: The International Society of Blood Transfusion
(ISBT).
◉ What are the two main blood group systems focused on in this
chapter? Answer: ABO and H blood group systems.
◉ Who discovered the ABO blood group system? Answer: Karl
Landsteiner in 1900.
◉ What are the three major groups identified in the ABO blood group
system? Answer: A, B, and O.
◉ What is Landsteiner's rule regarding ABO antibodies? Answer:
Normal healthy individuals possess ABO antibodies to the blood group
antigens absent from their cells.
◉ What can occur if incompatible blood types are transfused? Answer:
Acute hemolytic transfusion reactions.
, ◉ Where are ABO antigens widely distributed in the body? Answer: In
red blood cells, lymphocytes, platelets, and most epithelial and
endothelial cells.
◉ At what stage of development are ABO antigens detectable? Answer:
At 5-6 weeks in utero.
◉ What is the role of the H antigen in the ABO blood group system?
Answer: It is critical for the expression of A and B antigens.
◉ What chromosome is the H antigen found on? Answer: Chromosome
19.
◉ What is the dominant allele for the H antigen? Answer: H, with a
frequency greater than 99.99%.
◉ What enzyme does the H antigen gene code for? Answer: L-
Fucosyltransferase.
◉ How is the A antigen formed? Answer: By attaching N-
acetylgalactosamine to the third carbon of galactose on the H antigen.
◉ How is the B antigen formed? Answer: By attaching D-galactose to
the third carbon of galactose on the H antigen.
