ASCP Immunohematology Exam ACTUAL
QUESTIONS AND CORRECT ANSWERS
Define dosage - Corrrect answers✔✔Dosage is defined as an antibody reacting stronger with
homozygous cells (such as KK) than with heterozygous cells (Kk)
List the antigens that commonly show dosage? - Corrrect answers✔✔Kell.
M.
N.
S, little s.
F.y.a, F.y.b
J.k.a, J.k.b.
Antigens of the Rh system.
Is the Duffy antigens F.y.a and F.y.b more prevalent in African Americans or in whites? -
Corrrect answers✔✔In African Americans.
70% African Americans and it is very rare in whites.
What does the term heterozygous mean? - Corrrect answers✔✔A diploid organism is
heterozygous at a gene locus when its cells contain two different alleles of a gene. The cell or
organism is called a heterozygote specifically for the allele in question, and therefore,
heterozygosity refers to a specific genotype.
What distinguishes A1 from A2 blood groups? - Corrrect answers✔✔An A2 person may form
anti-A1, but an A1 person will not form anti-A1.
,What is the only A.B.O phenotype that is incompatible with O cells. - Corrrect
answers✔✔Bombay.
The red cells of Bombay show a negative reaction to anti-H because the cells contain no H
substance.
A Bombay individual has a phenotype little hh and will type as group O.
What antibodies are formed by an Bombay individual? - Corrrect answers✔✔Anti-A, Anti-B,
Anti-H.
Because a Bombay individual has three antibodies, the only compatible blood must be from
another Bombay donor.
Acquired B antigens have been found in what type of person? - Corrrect answers✔✔A-persons.
Is Acquired B phenotype a transient condition? - Corrrect answers✔✔Yes, Over time, when the
root cause of the bacterial enzyme removal of the acetyl group is resolved, a patient's blood type
will no longer show an acquired B antigen.
What causes Acquired B phenotype. - Corrrect answers✔✔Acquired B occurs when the RBCs
from a blood group A patient come in contact with bacterial enzymes known as "deacetylases"
carried by bacteria that live in the colon - typically gram-negative rods.
What is Acquired B usually associated with? - Corrrect answers✔✔colorectal malignancy,
gastrointestinal obstruction, or gram-negative sepsis -where those bacteria can contact the RBCs.
What does a strong reaction in reverse grouping suggest when it doesn't match the forward
grouping? - Corrrect answers✔✔That the discrepancy is in forward grouping.
, What should be done if a strong reaction is seen in the reverse that doesn't match the forward? -
Corrrect answers✔✔Incubate washed red cells at room temperature with anti-A and anti-A,B
which will enhance reactions.
What typing results are most likely to occur when a patient has an acquired B antigen? - Corrrect
answers✔✔Anti-A-4+
Anti-B-1+
A1 cells-negative
B cells-4+
Which blood group has the least amount of H antigen? - Corrrect answers✔✔A1B.
This is due to both A and B epitope present on red cells compromising the availability of H
epitope. A1B cells will yield weak reactions with anti H lectin.
What type RBC's can be transfused to an A2 person with anti-A1? - Corrrect answers✔✔A or O
because A1 is typically only reactive at room temperature.
What might the forward and reverse type look like in a patient with a cold autoantibody? -
Corrrect answers✔✔Forward and reverse A.B.O results as well as the auto control would be
positive.
What should be done for a cold autoantibody? - Corrrect answers✔✔Wash the cells with warm
saline and autoadsorb the serum at 4 degrees Celsius .
Washing the cells with warm saline may elite the autoantibody, allowing a valid forward type.
The serum should be adsorbed using washed cells until the auto control is negative. Then the
autoadsorbed serum should be used for reverse typing.
What is adsorption? - Corrrect answers✔✔Procedure used to bind antibodies to RBC's in order
to remove them from the plasma and better analyze the antibodies that are left behind.
QUESTIONS AND CORRECT ANSWERS
Define dosage - Corrrect answers✔✔Dosage is defined as an antibody reacting stronger with
homozygous cells (such as KK) than with heterozygous cells (Kk)
List the antigens that commonly show dosage? - Corrrect answers✔✔Kell.
M.
N.
S, little s.
F.y.a, F.y.b
J.k.a, J.k.b.
Antigens of the Rh system.
Is the Duffy antigens F.y.a and F.y.b more prevalent in African Americans or in whites? -
Corrrect answers✔✔In African Americans.
70% African Americans and it is very rare in whites.
What does the term heterozygous mean? - Corrrect answers✔✔A diploid organism is
heterozygous at a gene locus when its cells contain two different alleles of a gene. The cell or
organism is called a heterozygote specifically for the allele in question, and therefore,
heterozygosity refers to a specific genotype.
What distinguishes A1 from A2 blood groups? - Corrrect answers✔✔An A2 person may form
anti-A1, but an A1 person will not form anti-A1.
,What is the only A.B.O phenotype that is incompatible with O cells. - Corrrect
answers✔✔Bombay.
The red cells of Bombay show a negative reaction to anti-H because the cells contain no H
substance.
A Bombay individual has a phenotype little hh and will type as group O.
What antibodies are formed by an Bombay individual? - Corrrect answers✔✔Anti-A, Anti-B,
Anti-H.
Because a Bombay individual has three antibodies, the only compatible blood must be from
another Bombay donor.
Acquired B antigens have been found in what type of person? - Corrrect answers✔✔A-persons.
Is Acquired B phenotype a transient condition? - Corrrect answers✔✔Yes, Over time, when the
root cause of the bacterial enzyme removal of the acetyl group is resolved, a patient's blood type
will no longer show an acquired B antigen.
What causes Acquired B phenotype. - Corrrect answers✔✔Acquired B occurs when the RBCs
from a blood group A patient come in contact with bacterial enzymes known as "deacetylases"
carried by bacteria that live in the colon - typically gram-negative rods.
What is Acquired B usually associated with? - Corrrect answers✔✔colorectal malignancy,
gastrointestinal obstruction, or gram-negative sepsis -where those bacteria can contact the RBCs.
What does a strong reaction in reverse grouping suggest when it doesn't match the forward
grouping? - Corrrect answers✔✔That the discrepancy is in forward grouping.
, What should be done if a strong reaction is seen in the reverse that doesn't match the forward? -
Corrrect answers✔✔Incubate washed red cells at room temperature with anti-A and anti-A,B
which will enhance reactions.
What typing results are most likely to occur when a patient has an acquired B antigen? - Corrrect
answers✔✔Anti-A-4+
Anti-B-1+
A1 cells-negative
B cells-4+
Which blood group has the least amount of H antigen? - Corrrect answers✔✔A1B.
This is due to both A and B epitope present on red cells compromising the availability of H
epitope. A1B cells will yield weak reactions with anti H lectin.
What type RBC's can be transfused to an A2 person with anti-A1? - Corrrect answers✔✔A or O
because A1 is typically only reactive at room temperature.
What might the forward and reverse type look like in a patient with a cold autoantibody? -
Corrrect answers✔✔Forward and reverse A.B.O results as well as the auto control would be
positive.
What should be done for a cold autoantibody? - Corrrect answers✔✔Wash the cells with warm
saline and autoadsorb the serum at 4 degrees Celsius .
Washing the cells with warm saline may elite the autoantibody, allowing a valid forward type.
The serum should be adsorbed using washed cells until the auto control is negative. Then the
autoadsorbed serum should be used for reverse typing.
What is adsorption? - Corrrect answers✔✔Procedure used to bind antibodies to RBC's in order
to remove them from the plasma and better analyze the antibodies that are left behind.
