ASCP Immunohematology Exam ACTUAL
QUESTIONS AND CORRECT ANSWERS
Define dosage - CORRECT 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? - CORRECT 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? - CORRECT ANSWERS In African Americans.
70% African Americans and it is very rare in whites.
What does the term heterozygous mean? - CORRECT 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? - CORRECT 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. -
CORRECT 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? - CORRECT
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? - CORRECT
ANSWERS A-persons.
Is Acquired B phenotype a transient condition? - CORRECT 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. - CORRECT 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? - CORRECT 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? - CORRECT 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? - CORRECT 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? - CORRECT ANSWERS Anti-A-4+
Anti-B-1+
A1 cells-negative
B cells-4+
Which blood group has the least amount of H antigen? - CORRECT
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? - CORRECT
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? - CORRECT 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? - CORRECT 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.
QUESTIONS AND CORRECT ANSWERS
Define dosage - CORRECT 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? - CORRECT 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? - CORRECT ANSWERS In African Americans.
70% African Americans and it is very rare in whites.
What does the term heterozygous mean? - CORRECT 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? - CORRECT 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. -
CORRECT 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? - CORRECT
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? - CORRECT
ANSWERS A-persons.
Is Acquired B phenotype a transient condition? - CORRECT 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. - CORRECT 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? - CORRECT 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? - CORRECT 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? - CORRECT 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? - CORRECT ANSWERS Anti-A-4+
Anti-B-1+
A1 cells-negative
B cells-4+
Which blood group has the least amount of H antigen? - CORRECT
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? - CORRECT
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? - CORRECT 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? - CORRECT 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.
