BLOOD BANK FINAL EXAM PAPER 2026
COMPLETE ANSWERS AND STUDY GUIDE
TRANSFUSION SERVICES EDITION
◉ List the methods used in the blood bank to detect antibodies and
red cell antigens, and describe the principles.
Answer: AHG: Acts as a "bridge" between IgG molecules on RBCs
Albumin (22%): Reduces the zeta potential between RBCs
LISS: Enhances RBCs uptake of antibody and reduces zeta potential
PEG: Removes water molecules surrounding RBCs to concentrate the
antibodies present
All testing boils down to two things: Detecting antibodies in serum,
detecting antigens on RBCs.
ENDPOINT of nearly all basic tests is agglutination
◉ Identify the various factors that affect agglutination reactions.
Answer: Centrifugation, antigen-antibody ratio, pH, temperature,
immunoglobulin type, and enhancement media affect agglutination
reactions.
, ◉ State the inheritance pattern for ABO and Hh, and resultant gene
products.
Answer: A and B are codominant alleles that produce transferases
while O is an amorph gene with no transferase. ABO genes are on
chromosome 9.
H is dominant and produces fucosyltransferase while h is an amorph
gene on chromosome 19
◉ Explain the formation of H, A, and B antigens on the surface of the
RBC and in secretions.
Answer: H antigen forms when fucosyltransferase adds fucose to the
precursor chain.
A transferase adds N-acetylgalactosamine to form A antigen
B transferase adds galactose to form B antigen
Secretors also express ABH substances in body fluids.
◉ Predict the ABO phenotypes and genotypes of offspring from
various ABO matings.
Answer: A phenotype may be AA or AO
B may be BB or BO, AB is AB
O is OO.
Punnett squares are used to predict offspring inheritance patterns
such as AO × BO producing A, B, AB, or O offspring.
COMPLETE ANSWERS AND STUDY GUIDE
TRANSFUSION SERVICES EDITION
◉ List the methods used in the blood bank to detect antibodies and
red cell antigens, and describe the principles.
Answer: AHG: Acts as a "bridge" between IgG molecules on RBCs
Albumin (22%): Reduces the zeta potential between RBCs
LISS: Enhances RBCs uptake of antibody and reduces zeta potential
PEG: Removes water molecules surrounding RBCs to concentrate the
antibodies present
All testing boils down to two things: Detecting antibodies in serum,
detecting antigens on RBCs.
ENDPOINT of nearly all basic tests is agglutination
◉ Identify the various factors that affect agglutination reactions.
Answer: Centrifugation, antigen-antibody ratio, pH, temperature,
immunoglobulin type, and enhancement media affect agglutination
reactions.
, ◉ State the inheritance pattern for ABO and Hh, and resultant gene
products.
Answer: A and B are codominant alleles that produce transferases
while O is an amorph gene with no transferase. ABO genes are on
chromosome 9.
H is dominant and produces fucosyltransferase while h is an amorph
gene on chromosome 19
◉ Explain the formation of H, A, and B antigens on the surface of the
RBC and in secretions.
Answer: H antigen forms when fucosyltransferase adds fucose to the
precursor chain.
A transferase adds N-acetylgalactosamine to form A antigen
B transferase adds galactose to form B antigen
Secretors also express ABH substances in body fluids.
◉ Predict the ABO phenotypes and genotypes of offspring from
various ABO matings.
Answer: A phenotype may be AA or AO
B may be BB or BO, AB is AB
O is OO.
Punnett squares are used to predict offspring inheritance patterns
such as AO × BO producing A, B, AB, or O offspring.
