ASCP Blood Bank Exam Prep 2025–2026 |
SBB/MLS Test Bank | 452+ Blood Banking
Practice Questions with Correct Answers &
Explanations.
What type of serological testing does the blood
bank technologist perform when determining the
blood group of a patient?
phenotyping
If anti-K reacts 3+ with a donor cell with a
genotype KK and 2+ with a Kk cell, the antibody
is demonstrating:
Dosage
Carla expresses the blood group antigens Fya, Fyb, and Xga. James shows expressions of none of
these antigens. What factor(s) may account for the absence of these antigens in James?
Gender and Race. The frequency of Duffy antigens Fya and Fyb varies
with race. The Fy(a−b−) phenotype occurs in almost
70% of African Americans and is very rare in whites.
The Xga antigen is X-linked and, therefore, expressed more frequently in women (who may
inherit the antigen from either parent) than in men.
Which of the following statements is true?
A. An individual with the BO genotype is
homozygous for B antigen
B. An individual with the BB genotype is
homozygous for B antigen
C. An individual with the OO genotype is
heterozygous for O antigen
D. An individual with the AB phenotype is
homozygous for A and B antigens
B. An individual with the BB genotype is
homozygous for B antigen
,Which genotype is heterozygous for C?
A. DCe/dce
B. DCE/DCE
C. Dce/dce
D. DCE/dCe
A. DCe/dce
Which genotype(s) will give rise to the Bombay phenotype?
The Bombay phenotype will be expressed only when no H substance is present. The Oh type is
expressed by the genotype hh. Bombays produce naturally occurring anti-H, and their serum
agglutinates group
O red cells in addition to red cells from groups A, B, and AB persons.
Meiosis in cell division is limited to the ova and sperm producing four gametes containing what
complement of DNA?
1N. Meiosis involves two nuclear divisions in succession resulting in four gametocytes each
containing half the number of chromosomes found in somatic cells or 1N.
A cell that is not actively dividing is said to be in:
Interphase, The cell is engaged in metabolic activity. Chromosomes are not clearly discerned;
however, nucleoli may be
visible
Which of the following describes the expression of most blood group antigens?
Codominant
What blood type is not possible for an offspring of an AO and BO mating?
All are possible
The alleged father of a child in a disputed case of paternity is blood group AB. The mother is
group O and the child is group O. What type of exclusion is this?
-Indirect/secondary/second order
An indirect/secondary/second order exclusion occurs when a genetic marker is absent in the
child but should have been transmitted by the alleged father. In this case, either A or B should
be present in the child.
If the frequency of gene Y is 0.4 and the frequency of gene Z is 0.5, one would expect that they
should occur together 0.2 (20%) of the time. In actuality,
they are found together 32% of the time. This is an example of:
,Linkage disequilibrium.
Linkage disequilibrium is a phenomenon in which alleles situated in close proximity on a
chromosome associate with one another more than would be expected from individual allelic
frequencies.
In this type of inheritance, the father carries the trait on his X chromosome. He has no sons with
the trait because he passed his Y chromosome to his sons; however, all his daughters will
express the trait.
Autosomal Dominant
In the Hardy-Weinberg formula, p2 represents:
In the Hardy-Weinberg formula p2 + 2pq + q2, p2 and q2 represent homozygous expressions
and 2pq represents heterozygous expression. This formula is
used in population genetics to determine the frequency of different alleles.
What is the Hardy-Weinberg formula?
p2 + 2pq + q2 = 1
Why do IgM antibodies, such as those formed against the ABO antigens, have the ability to
directly agglutinate red blood cells (RBCs) and cause visible agglutination?
IgM antibodies are larger molecules and have the ability to bind more antigen
Which of the following enhancement mediums decreases the zeta potential, allowing antibody
and antigen to come closer together?
LISS.
LISS contains a reduced concentration of NaCl (0.2%) and results in a reduction in charged ions
within the ionic cloud, decreasing the zeta potential and facilitating antigen and antibody
interaction.
This type of antibody response is analogous to an anamnestic antibody reaction.
Secondary.
An anamnestic response is a secondary immune response in which memory lymphocytes
respond rapidly to foreign antigen in producing specific antibody. The antibodies are IgG and are
produced
at lower doses of antigen than in the primary response.
Which antibodies to a component of complement are contained in the rabbit polyspecific
antihuman globulin reagent for detection of in vivo sensitization?
, In the DAT (direct antiglobulin test), rabbit
polyspecific antisera contains both an anti-human IgG component and an antibody against the
C3d component of complement.
Which of the following distinguishes A1 from A2 blood groups?
A. A2 antigen will not react with anti-A, A1 will
react strongly (4+)
B. An A2 person may form anti-A1; an A1 person
will not form anti-A1
C. An A1 person may form anti-A2, an A2 person
will not form anti-A1
D. A2 antigen will not react with anti-A from a nonimmunized donor; A1 will react with any anti-
A
B. An A2 person may form anti-A1; an A1 person will not form anti-A1
A patient's serum is incompatible with O cells. The patient RBCs give a negative reaction to anti-
H lectin. What is the most likely cause of these results?
Bombay is the only ABO phenotype incompatible with O cells. The red cells of a Bombay show a
negative reaction to anti-H because the cells contain no H substance
What antibodies are formed by a Bombay
individual?
Anti-A, B, and H
Acquired B antigens have been found in:
Group A persons.
Blood is crossmatched on an A positive person with a negative antibody screen. The patient
received a
transfusion of A positive RBCs 3 years ago. The donors chosen for crossmatch were A positive.
The crossmatch was run on the Ortho Provue and yielded 3+ incompatibility. How can these
results be explained?
The patient is likely an A2 with anti-A1 which is causing reactivity in the crossmatch. A negative
antibody screen rules out the possibility of an antibody to a high-frequency antigen, and two
donor units incompatible rules out an antibody to a low-frequency antigen.
A patient's red cells forward as group O, serum agglutinates B cells (4+) only. Your next step
would be:
SBB/MLS Test Bank | 452+ Blood Banking
Practice Questions with Correct Answers &
Explanations.
What type of serological testing does the blood
bank technologist perform when determining the
blood group of a patient?
phenotyping
If anti-K reacts 3+ with a donor cell with a
genotype KK and 2+ with a Kk cell, the antibody
is demonstrating:
Dosage
Carla expresses the blood group antigens Fya, Fyb, and Xga. James shows expressions of none of
these antigens. What factor(s) may account for the absence of these antigens in James?
Gender and Race. The frequency of Duffy antigens Fya and Fyb varies
with race. The Fy(a−b−) phenotype occurs in almost
70% of African Americans and is very rare in whites.
The Xga antigen is X-linked and, therefore, expressed more frequently in women (who may
inherit the antigen from either parent) than in men.
Which of the following statements is true?
A. An individual with the BO genotype is
homozygous for B antigen
B. An individual with the BB genotype is
homozygous for B antigen
C. An individual with the OO genotype is
heterozygous for O antigen
D. An individual with the AB phenotype is
homozygous for A and B antigens
B. An individual with the BB genotype is
homozygous for B antigen
,Which genotype is heterozygous for C?
A. DCe/dce
B. DCE/DCE
C. Dce/dce
D. DCE/dCe
A. DCe/dce
Which genotype(s) will give rise to the Bombay phenotype?
The Bombay phenotype will be expressed only when no H substance is present. The Oh type is
expressed by the genotype hh. Bombays produce naturally occurring anti-H, and their serum
agglutinates group
O red cells in addition to red cells from groups A, B, and AB persons.
Meiosis in cell division is limited to the ova and sperm producing four gametes containing what
complement of DNA?
1N. Meiosis involves two nuclear divisions in succession resulting in four gametocytes each
containing half the number of chromosomes found in somatic cells or 1N.
A cell that is not actively dividing is said to be in:
Interphase, The cell is engaged in metabolic activity. Chromosomes are not clearly discerned;
however, nucleoli may be
visible
Which of the following describes the expression of most blood group antigens?
Codominant
What blood type is not possible for an offspring of an AO and BO mating?
All are possible
The alleged father of a child in a disputed case of paternity is blood group AB. The mother is
group O and the child is group O. What type of exclusion is this?
-Indirect/secondary/second order
An indirect/secondary/second order exclusion occurs when a genetic marker is absent in the
child but should have been transmitted by the alleged father. In this case, either A or B should
be present in the child.
If the frequency of gene Y is 0.4 and the frequency of gene Z is 0.5, one would expect that they
should occur together 0.2 (20%) of the time. In actuality,
they are found together 32% of the time. This is an example of:
,Linkage disequilibrium.
Linkage disequilibrium is a phenomenon in which alleles situated in close proximity on a
chromosome associate with one another more than would be expected from individual allelic
frequencies.
In this type of inheritance, the father carries the trait on his X chromosome. He has no sons with
the trait because he passed his Y chromosome to his sons; however, all his daughters will
express the trait.
Autosomal Dominant
In the Hardy-Weinberg formula, p2 represents:
In the Hardy-Weinberg formula p2 + 2pq + q2, p2 and q2 represent homozygous expressions
and 2pq represents heterozygous expression. This formula is
used in population genetics to determine the frequency of different alleles.
What is the Hardy-Weinberg formula?
p2 + 2pq + q2 = 1
Why do IgM antibodies, such as those formed against the ABO antigens, have the ability to
directly agglutinate red blood cells (RBCs) and cause visible agglutination?
IgM antibodies are larger molecules and have the ability to bind more antigen
Which of the following enhancement mediums decreases the zeta potential, allowing antibody
and antigen to come closer together?
LISS.
LISS contains a reduced concentration of NaCl (0.2%) and results in a reduction in charged ions
within the ionic cloud, decreasing the zeta potential and facilitating antigen and antibody
interaction.
This type of antibody response is analogous to an anamnestic antibody reaction.
Secondary.
An anamnestic response is a secondary immune response in which memory lymphocytes
respond rapidly to foreign antigen in producing specific antibody. The antibodies are IgG and are
produced
at lower doses of antigen than in the primary response.
Which antibodies to a component of complement are contained in the rabbit polyspecific
antihuman globulin reagent for detection of in vivo sensitization?
, In the DAT (direct antiglobulin test), rabbit
polyspecific antisera contains both an anti-human IgG component and an antibody against the
C3d component of complement.
Which of the following distinguishes A1 from A2 blood groups?
A. A2 antigen will not react with anti-A, A1 will
react strongly (4+)
B. An A2 person may form anti-A1; an A1 person
will not form anti-A1
C. An A1 person may form anti-A2, an A2 person
will not form anti-A1
D. A2 antigen will not react with anti-A from a nonimmunized donor; A1 will react with any anti-
A
B. An A2 person may form anti-A1; an A1 person will not form anti-A1
A patient's serum is incompatible with O cells. The patient RBCs give a negative reaction to anti-
H lectin. What is the most likely cause of these results?
Bombay is the only ABO phenotype incompatible with O cells. The red cells of a Bombay show a
negative reaction to anti-H because the cells contain no H substance
What antibodies are formed by a Bombay
individual?
Anti-A, B, and H
Acquired B antigens have been found in:
Group A persons.
Blood is crossmatched on an A positive person with a negative antibody screen. The patient
received a
transfusion of A positive RBCs 3 years ago. The donors chosen for crossmatch were A positive.
The crossmatch was run on the Ortho Provue and yielded 3+ incompatibility. How can these
results be explained?
The patient is likely an A2 with anti-A1 which is causing reactivity in the crossmatch. A negative
antibody screen rules out the possibility of an antibody to a high-frequency antigen, and two
donor units incompatible rules out an antibody to a low-frequency antigen.
A patient's red cells forward as group O, serum agglutinates B cells (4+) only. Your next step
would be:
