ASCP BLOOD BANK EXAM WITH
ELABORATED QUESTIONS AND ALL
CORRECT ANSWERS 2025
Describe the McLeod phenotype. - CORRECT ANSWER It affects only males and is a
rare phenotype with decreased Kell antigens expression. It includes the abnormal RBC
morphology, hemolytic anemia and neurological and muscular abnormalities. Some
males with McLeod phenotype also have the X-linked chronic granulomatous disease.
When is Rhogam given? - CORRECT ANSWER Rhogam is immune anti-D and is given
to Rh negative mothers who give birth to Rh positive babies and who do not have anti -D
already formed from previous pregnancies or transfusions.
What is kerinicterus caused by? - CORRECT ANSWER High levels of unconjugated
bilirubin which can cause brain damage to the infant.
At what age does an infant begin to develop their own antibodies? - CORRECT
ANSWER They do not develop antibodies until about 6 months of age. Any antibodies
detected in a cord blood sample come from the mother.
What is the most common reason a Rh negative woman would have a positive antibody
screen? - CORRECT ANSWER Because of previously receiving Rhogam or passive
anti-D.
What is the protocol for screening whole blood donors for HIV-1 RNA? - CORRECT
ANSWER Pools of 16 donors are tested and if pool is reactive, samples from each
donor are tested.
Nucleic acid amplification (NAT) is performed on blood products to detect which
viruses? - CORRECT ANSWER HIV, Hepatitis C Virus and West Nile Virus.
What marker is the first to appear in hepatitis B infection? - CORRECT ANSWER
Hepatitis B Surface Antigen (HbsAg), which appears in as few as 5 days (5-28 days’
post exposure).
What marker indicates immunity to hepatitis B infection? - CORRECT ANSWER Anti-
HBs.
On what chromosome is the M.N.S blood antigen system found? - CORRECT
ANSWER On chromosome 4.
,What class of immunoglobulins are anti-M and anti-N? - CORRECT ANSWER IgM and
they are rarely associated with transfusion reactions.
They are cold reacting.
Are Anti-S, anti-s and anti-U associated with hemolytic transfusion reactions and
hemolytic disease of the newborn. - CORRECT ANSWER Yes.
Where are antigens of the M.N.S system located? - CORRECT ANSWER On one of
two glycoproteins: glycophorin A or glycophorin B.
Anti-M and anti-N. - CORRECT ANSWER IgM.
Naturally occurring.
Cold reacting.
Generally, clinically insignificant.
Not involved in H.T.R or H.D.F.N.
Anti S, Anti s, anti U. - CORRECT ANSWER IgG.
Acquired following exposure from pregnancy or transfusion.
Warm reacting.
Clinically significant.
Are involved in H.T.R. Or H.D.F.N.
Define dosage - CORRECT ANSWER 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 ANSWER 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.an and F.y.b more prevalent in African Americans or in whites?
- CORRECT ANSWER in African Americans.
70% African Americans and it is very rare in whites.
What does the term heterozygous mean? - CORRECT ANSWER 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 ANSWER 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
ANSWER 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 a Bombay individual? - CORRECT ANSWER 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 ANSWER
A-persons.
Is Acquired B phenotype a transient condition? - CORRECT ANSWER 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 ANSWER 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 ANSWER 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 ANSWER 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 ANSWER 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 ANSWER Anti-A-4+
Anti-B-1+
A1 cells-negative
B cells-4+
Which blood group has the least amount of H antigen? - CORRECT ANSWER 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
ANSWER A or O because A1 is typically only reactive at room temperature.
ELABORATED QUESTIONS AND ALL
CORRECT ANSWERS 2025
Describe the McLeod phenotype. - CORRECT ANSWER It affects only males and is a
rare phenotype with decreased Kell antigens expression. It includes the abnormal RBC
morphology, hemolytic anemia and neurological and muscular abnormalities. Some
males with McLeod phenotype also have the X-linked chronic granulomatous disease.
When is Rhogam given? - CORRECT ANSWER Rhogam is immune anti-D and is given
to Rh negative mothers who give birth to Rh positive babies and who do not have anti -D
already formed from previous pregnancies or transfusions.
What is kerinicterus caused by? - CORRECT ANSWER High levels of unconjugated
bilirubin which can cause brain damage to the infant.
At what age does an infant begin to develop their own antibodies? - CORRECT
ANSWER They do not develop antibodies until about 6 months of age. Any antibodies
detected in a cord blood sample come from the mother.
What is the most common reason a Rh negative woman would have a positive antibody
screen? - CORRECT ANSWER Because of previously receiving Rhogam or passive
anti-D.
What is the protocol for screening whole blood donors for HIV-1 RNA? - CORRECT
ANSWER Pools of 16 donors are tested and if pool is reactive, samples from each
donor are tested.
Nucleic acid amplification (NAT) is performed on blood products to detect which
viruses? - CORRECT ANSWER HIV, Hepatitis C Virus and West Nile Virus.
What marker is the first to appear in hepatitis B infection? - CORRECT ANSWER
Hepatitis B Surface Antigen (HbsAg), which appears in as few as 5 days (5-28 days’
post exposure).
What marker indicates immunity to hepatitis B infection? - CORRECT ANSWER Anti-
HBs.
On what chromosome is the M.N.S blood antigen system found? - CORRECT
ANSWER On chromosome 4.
,What class of immunoglobulins are anti-M and anti-N? - CORRECT ANSWER IgM and
they are rarely associated with transfusion reactions.
They are cold reacting.
Are Anti-S, anti-s and anti-U associated with hemolytic transfusion reactions and
hemolytic disease of the newborn. - CORRECT ANSWER Yes.
Where are antigens of the M.N.S system located? - CORRECT ANSWER On one of
two glycoproteins: glycophorin A or glycophorin B.
Anti-M and anti-N. - CORRECT ANSWER IgM.
Naturally occurring.
Cold reacting.
Generally, clinically insignificant.
Not involved in H.T.R or H.D.F.N.
Anti S, Anti s, anti U. - CORRECT ANSWER IgG.
Acquired following exposure from pregnancy or transfusion.
Warm reacting.
Clinically significant.
Are involved in H.T.R. Or H.D.F.N.
Define dosage - CORRECT ANSWER 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 ANSWER 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.an and F.y.b more prevalent in African Americans or in whites?
- CORRECT ANSWER in African Americans.
70% African Americans and it is very rare in whites.
What does the term heterozygous mean? - CORRECT ANSWER 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 ANSWER 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
ANSWER 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 a Bombay individual? - CORRECT ANSWER 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 ANSWER
A-persons.
Is Acquired B phenotype a transient condition? - CORRECT ANSWER 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 ANSWER 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 ANSWER 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 ANSWER 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 ANSWER 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 ANSWER Anti-A-4+
Anti-B-1+
A1 cells-negative
B cells-4+
Which blood group has the least amount of H antigen? - CORRECT ANSWER 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
ANSWER A or O because A1 is typically only reactive at room temperature.
