Harr ASCP Review – Complete Study Guide for Clinical Laboratory
Science Certification Exam
What type of serological testing does the blood bank technologist perform when determining
the blood group of a patient? - correct answer Phenotyping
If anti-K reacts 3+ with a donor cell with a genotype KK and 2+ with a Kk cell, the antibody is
demonstrating: - correct answer 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? -
correct answer Gender and race
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 - correct answer An
individual with the BB genotype is homozygous for B antigen
Which genotype is heterozygous for C? - correct answer DCe/dce
Which genotype(s) will give rise to the Bombay phenotype? - correct answer hh only
Meiosis in cell division is limited to the ova and sperm producing four gametes containing what
complement of DNA? - correct answer 1N
A cell that is not actively dividing is said to be in: - correct answer Interphase
Which of the following describes the expression of most blood group antigens? - correct
answer Codominant
What blood type is not possible for an offspring of an AO and BO mating? - correct answer 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? - correct answer
Indirect/secondary/second order
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: - correct answer Linkage disequilibrium
,In the Hardy-Weinberg formula, p^2 represents: - correct answer The homozygous population
of one allele
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. - correct answer X-linked dominant
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? - correct answer 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? - correct answer LISS
This type of antibody response is analogous to an anamnestic antibody reaction. - correct
answer Secondary
Which antibodies to a component of complement are contained in the rabbit polyspecific
antihuman globulin reagent for detection of in vivo sensitization? - correct answer Anti-IgG and
anti-C3d
Which of the following distinguishes A1 from A2 blood groups? - correct answer 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? - correct answer The patient may be a
Bombay
What antibodies are formed by a Bombay individual? - correct answer Anti-A, B, and H
Acquired B antigens have been found in: - correct answer 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? - correct answer The patient is an A2 with anti-A1
A patient's red cells forward as group O, serum agglutinates B cells (4+) only. Your next step
would be: - correct answer Incubate washed red cells with anti-A1 and anti-A,B for 30 minutes
at room temperature
Which 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 neg, B cells 4+
Which blood group has the least amount of H antigen? - correct answer A1B
What type RBCs can be transfused to an A2 person with anti-A1? - correct answer A or O
,What should be done if all forward and reverse ABO results as well as the autocontrol are
positive? - correct answer Wash the cells with warm saline, autoadsorb the serum at 4°C
What should be done if all forward and reverse ABO results are negative? - correct answer
Incubate at 22°C or 4°C to enhance weak expression
N-acetyl-D-galactosamine is the immunodominant carbohydrate that reacts with: - correct
answer Dolichos biflorus
A stem cell transplant patient was retyped when she was transferred from another hospital.
What is the most likely cause of the following results?
Patient cells: Anti-A, neg; Anti-B, 4+
Patient serum: A1 cells, neg; B cells, neg - correct answer Immunodeficiency
What reaction would be the same for an A1 and an A2 person? - correct answer Positive
reaction with anti-A,B
A female patient at 28 weeks' gestation yields the following results:
Patient cells: Anti-A 3+; Anti-B 4+
Patient serum: A1 cells, neg; B cells 1+; O cells, 1+ - correct answer Alloantibody in patient
serum
Which condition would most likely be responsible for the following typing results?
Patient cells: Anti-A, neg; Anti-B, neg
Patient serum: A1 cells, neg; B cells, 4+ - correct answer Weak or excessive antigen(s)
Which of the following results is most likely discrepant?
Anti-A, neg; Anti-B, 4+
A1 cells, neg; B cells, neg - correct answer Negative A1 cells
A 61-year-old male with a history of multiple myeloma had a stem cell transplant 3 years ago.
The donor was O positive and the recipient was B positive. He is admitted to a community
hospital for fatigue and nausea. Typing results reveal the following:
Anti-A = 0; Anti-B =0; Anti-A,B = 0; Anti-D = 4+; A1 cells = 4+; B cells = 0
How would you report this type? - correct answer Undetermined
A complete Rh typing for antigens C, c, D, E, and e revealed negative results for C, D, and E. How
is the individual designated? - correct answer Rh negative
How is an individual with genotype Dce/dce classified? - correct answer Rh positive
, If a patient has a positive direct antiglobulin test, should you perform a weak D test on the
cells? - correct answer No, the cells are already coated with antibody
Which donor unit is selected for a recipient with anti-c? - correct answer r'ry
Which genotype usually shows the strongest reaction with anti-D? - correct answer D-/D-
Why is testing for Rh antigens and antibodies different from ABO testing?
a. ABO reactions are primarily due to IgM antibodies and usually occur at room temperature;
Rh antibodies are IgG and agglutination usually requires a 37°C incubation and enhancement
media
b. ABO antigens are attached to receptors on the outside of the red cell and do not require any
special enhancement for testing; Rh antigens are loosely attached to the red cell membrane
and require enhancement for detection
c. Both ABO and Rh antigens and antibodies have similar structures, but Rh antibodies are
configured so that special techniques are needed to facilitate binding to Rh antigens
d. There is no difference in ABO and Rh testing; both may be conducted at room temperature
with no special enhancement needed for reaction - correct answer ABO reactions are primarily
due to IgM antibodies and usually occur at room temperature; Rh antibodies are IgG and
agglutination usually requires a 37°C incubation and enhancement media
Testing reveals a weak D that reacts 1+ after indirect antiglobulin testing (IAT). How is this
result classified? - correct answer Rh positive
What is one possible genotype for a patient who develops anti-C antibody? - correct answer rr
A patient developed a combination of Rh antibodies: anti-C, anti-E, and anti-D. Can compatible
blood be found for this patient? - correct answer rr blood could be used without causing a
problem
A patient tests positive for weak D but also appears to have anti-D in his serum. What may be
the problem? - correct answer A D mosaic may make antibodies to missing antigen parts
Which offspring is not possible from a mother who is R1R2 and a father who is R1r? - correct
answer DcE/DcE
Why is testing a pregnant woman for weak D not required? - correct answer An Rh-positive
fetus may yield false positive results in a fetal maternal bleed
What antibodies could an R1R1 make if exposed to R2R2 blood? - correct answer Anti-E and
anti-c
What does the genotype —/—represent in the Rh system? - correct answer Rh null
Science Certification Exam
What type of serological testing does the blood bank technologist perform when determining
the blood group of a patient? - correct answer Phenotyping
If anti-K reacts 3+ with a donor cell with a genotype KK and 2+ with a Kk cell, the antibody is
demonstrating: - correct answer 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? -
correct answer Gender and race
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 - correct answer An
individual with the BB genotype is homozygous for B antigen
Which genotype is heterozygous for C? - correct answer DCe/dce
Which genotype(s) will give rise to the Bombay phenotype? - correct answer hh only
Meiosis in cell division is limited to the ova and sperm producing four gametes containing what
complement of DNA? - correct answer 1N
A cell that is not actively dividing is said to be in: - correct answer Interphase
Which of the following describes the expression of most blood group antigens? - correct
answer Codominant
What blood type is not possible for an offspring of an AO and BO mating? - correct answer 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? - correct answer
Indirect/secondary/second order
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: - correct answer Linkage disequilibrium
,In the Hardy-Weinberg formula, p^2 represents: - correct answer The homozygous population
of one allele
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. - correct answer X-linked dominant
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? - correct answer 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? - correct answer LISS
This type of antibody response is analogous to an anamnestic antibody reaction. - correct
answer Secondary
Which antibodies to a component of complement are contained in the rabbit polyspecific
antihuman globulin reagent for detection of in vivo sensitization? - correct answer Anti-IgG and
anti-C3d
Which of the following distinguishes A1 from A2 blood groups? - correct answer 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? - correct answer The patient may be a
Bombay
What antibodies are formed by a Bombay individual? - correct answer Anti-A, B, and H
Acquired B antigens have been found in: - correct answer 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? - correct answer The patient is an A2 with anti-A1
A patient's red cells forward as group O, serum agglutinates B cells (4+) only. Your next step
would be: - correct answer Incubate washed red cells with anti-A1 and anti-A,B for 30 minutes
at room temperature
Which 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 neg, B cells 4+
Which blood group has the least amount of H antigen? - correct answer A1B
What type RBCs can be transfused to an A2 person with anti-A1? - correct answer A or O
,What should be done if all forward and reverse ABO results as well as the autocontrol are
positive? - correct answer Wash the cells with warm saline, autoadsorb the serum at 4°C
What should be done if all forward and reverse ABO results are negative? - correct answer
Incubate at 22°C or 4°C to enhance weak expression
N-acetyl-D-galactosamine is the immunodominant carbohydrate that reacts with: - correct
answer Dolichos biflorus
A stem cell transplant patient was retyped when she was transferred from another hospital.
What is the most likely cause of the following results?
Patient cells: Anti-A, neg; Anti-B, 4+
Patient serum: A1 cells, neg; B cells, neg - correct answer Immunodeficiency
What reaction would be the same for an A1 and an A2 person? - correct answer Positive
reaction with anti-A,B
A female patient at 28 weeks' gestation yields the following results:
Patient cells: Anti-A 3+; Anti-B 4+
Patient serum: A1 cells, neg; B cells 1+; O cells, 1+ - correct answer Alloantibody in patient
serum
Which condition would most likely be responsible for the following typing results?
Patient cells: Anti-A, neg; Anti-B, neg
Patient serum: A1 cells, neg; B cells, 4+ - correct answer Weak or excessive antigen(s)
Which of the following results is most likely discrepant?
Anti-A, neg; Anti-B, 4+
A1 cells, neg; B cells, neg - correct answer Negative A1 cells
A 61-year-old male with a history of multiple myeloma had a stem cell transplant 3 years ago.
The donor was O positive and the recipient was B positive. He is admitted to a community
hospital for fatigue and nausea. Typing results reveal the following:
Anti-A = 0; Anti-B =0; Anti-A,B = 0; Anti-D = 4+; A1 cells = 4+; B cells = 0
How would you report this type? - correct answer Undetermined
A complete Rh typing for antigens C, c, D, E, and e revealed negative results for C, D, and E. How
is the individual designated? - correct answer Rh negative
How is an individual with genotype Dce/dce classified? - correct answer Rh positive
, If a patient has a positive direct antiglobulin test, should you perform a weak D test on the
cells? - correct answer No, the cells are already coated with antibody
Which donor unit is selected for a recipient with anti-c? - correct answer r'ry
Which genotype usually shows the strongest reaction with anti-D? - correct answer D-/D-
Why is testing for Rh antigens and antibodies different from ABO testing?
a. ABO reactions are primarily due to IgM antibodies and usually occur at room temperature;
Rh antibodies are IgG and agglutination usually requires a 37°C incubation and enhancement
media
b. ABO antigens are attached to receptors on the outside of the red cell and do not require any
special enhancement for testing; Rh antigens are loosely attached to the red cell membrane
and require enhancement for detection
c. Both ABO and Rh antigens and antibodies have similar structures, but Rh antibodies are
configured so that special techniques are needed to facilitate binding to Rh antigens
d. There is no difference in ABO and Rh testing; both may be conducted at room temperature
with no special enhancement needed for reaction - correct answer ABO reactions are primarily
due to IgM antibodies and usually occur at room temperature; Rh antibodies are IgG and
agglutination usually requires a 37°C incubation and enhancement media
Testing reveals a weak D that reacts 1+ after indirect antiglobulin testing (IAT). How is this
result classified? - correct answer Rh positive
What is one possible genotype for a patient who develops anti-C antibody? - correct answer rr
A patient developed a combination of Rh antibodies: anti-C, anti-E, and anti-D. Can compatible
blood be found for this patient? - correct answer rr blood could be used without causing a
problem
A patient tests positive for weak D but also appears to have anti-D in his serum. What may be
the problem? - correct answer A D mosaic may make antibodies to missing antigen parts
Which offspring is not possible from a mother who is R1R2 and a father who is R1r? - correct
answer DcE/DcE
Why is testing a pregnant woman for weak D not required? - correct answer An Rh-positive
fetus may yield false positive results in a fetal maternal bleed
What antibodies could an R1R1 make if exposed to R2R2 blood? - correct answer Anti-E and
anti-c
What does the genotype —/—represent in the Rh system? - correct answer Rh null
