Blood Bank ASCP EXAM| 452 QUESTIONS|
WITH COMPLETE SOLUTIONS
Course
ASCP
1. Which blood group antigen is most immunogenic after the D antigen?
A. K (Kell)
B. Fyᵃ (Duffy)
C. Jkᵃ (Kidd)
D. S (MNS)
Answer: A. K (Kell)
Explanation: After the D antigen, Kell (K) is the most immunogenic. It's notorious for causing
hemolytic transfusion reactions and hemolytic disease of the fetus and newborn.
2. A patient is group A, Rh-negative, and has anti-D. What is the best choice for
RBC transfusion?
A. A positive
B. B negative
C. O negative
D. AB negative
Answer: C. O negative
Explanation: To avoid ABO and Rh incompatibility, O negative blood is safest for an A-
negative patient with anti-D.
3. What is the most likely cause of an ABO discrepancy where the forward type
is AB, but the reverse type shows reactions with both A and B cells?
A. Rouleaux formation
B. Cold autoantibody
C. Acquired B antigen
D. Group AB with cold alloantibody
Answer: B. Cold autoantibody
Explanation: Cold autoantibodies can cause reverse typing to appear falsely positive due to
nonspecific agglutination.
,4. Which antibody is commonly associated with delayed hemolytic transfusion
reactions and is often undetectable during initial screening?
A. Anti-E
B. Anti-Jkᵃ
C. Anti-M
D. Anti-Leᵃ
Answer: B. Anti-Jkᵃ
Explanation: Kidd antibodies (especially Jkᵃ) are often weak or transient but can cause severe
delayed hemolytic reactions.
5. Which antibody is most likely to be clinically insignificant?
A. Anti-Fyᵃ
B. Anti-Leᵃ
C. Anti-K
D. Anti-E
Answer: B. Anti-Leᵃ
Explanation: Lewis antibodies like anti-Leᵃ are typically IgM, do not cause HDFN, and are
considered insignificant for transfusion purposes.
6. What is the function of LISS (Low Ionic Strength Solution) in antibody
screening?
A. Enhances IgM detection
B. Reduces zeta potential and enhances IgG uptake
C. Inactivates complement
D. Removes autoantibodies
Answer: B. Reduces zeta potential and enhances IgG uptake
Explanation: LISS facilitates antibody binding by decreasing the ionic strength of the testing
environment, enhancing IgG detection.
7. Which of the following blood components should be irradiated for a neonate
undergoing intrauterine transfusion?
,A. Platelets only
B. RBCs only
C. All components
D. Cryoprecipitate
Answer: C. All components
Explanation: Irradiation of cellular components is mandatory to prevent transfusion-associated
graft-versus-host disease (TA-GVHD) in immunocompromised patients.
8. A patient with a warm autoantibody is being crossmatched. What is the best
strategy to ensure safe transfusion?
A. Transfuse ABO-compatible blood without testing
B. Use cold panel to rule out antibodies
C. Identify any underlying alloantibodies and issue least incompatible blood
D. Wait for autoantibody to clear
Answer: C. Identify any underlying alloantibodies and issue least incompatible blood
Explanation: Warm autoantibodies can mask alloantibodies. Adsorption techniques should be
used to rule out clinically significant antibodies.
9. Which of the following conditions is most commonly associated with anti-I?
A. Infectious mononucleosis
B. Mycoplasma pneumoniae infection
C. Pregnancy
D. Sickle cell disease
Answer: B. Mycoplasma pneumoniae infection
Explanation: Anti-I is a cold-reactive autoantibody linked to Mycoplasma infections and can
cause cold agglutinin disease.
10. What is the primary reason for performing an antibody screen in
pretransfusion testing?
A. Detect antibodies to ABO antigens
B. Detect unexpected alloantibodies
C. Determine Rh status
D. Confirm crossmatch compatibility
, Answer: B. Detect unexpected alloantibodies
Explanation: Antibody screens aim to detect non-ABO antibodies (usually IgG) that may cause
transfusion reactions or HDFN.
11. What is the most appropriate confirmatory test to determine weak D status?
A. Indirect antiglobulin test
B. Direct antiglobulin test (DAT)
C. Enzyme treatment
D. Adsorption and elution
Answer: A. Indirect antiglobulin test
Explanation: Weak D is tested by incubating red cells with anti-D, then adding AHG (indirect
antiglobulin phase). It's used to detect reduced D antigen expression.
12. Which antibody is most commonly associated with severe hemolytic disease of the fetus
and newborn (HDFN)?
A. Anti-M
B. Anti-K
C. Anti-Leᵇ
D. Anti-P1
Answer: B. Anti-K
Explanation: After anti-D, anti-K is the most severe cause of HDFN, as it can suppress fetal
erythropoiesis in addition to causing hemolysis.
13. A cord blood sample shows a positive DAT. Which of the following is the most likely
cause?
A. Maternal anti-D
B. Infant anti-A
C. Fetal anti-B
D. Maternal anti-Leᵃ
Answer: A. Maternal anti-D
Explanation: A positive DAT in a newborn most often indicates maternal IgG antibodies (like
anti-D) crossing the placenta and coating fetal red cells.
14. Which blood group system shows dosage effect most strongly?
WITH COMPLETE SOLUTIONS
Course
ASCP
1. Which blood group antigen is most immunogenic after the D antigen?
A. K (Kell)
B. Fyᵃ (Duffy)
C. Jkᵃ (Kidd)
D. S (MNS)
Answer: A. K (Kell)
Explanation: After the D antigen, Kell (K) is the most immunogenic. It's notorious for causing
hemolytic transfusion reactions and hemolytic disease of the fetus and newborn.
2. A patient is group A, Rh-negative, and has anti-D. What is the best choice for
RBC transfusion?
A. A positive
B. B negative
C. O negative
D. AB negative
Answer: C. O negative
Explanation: To avoid ABO and Rh incompatibility, O negative blood is safest for an A-
negative patient with anti-D.
3. What is the most likely cause of an ABO discrepancy where the forward type
is AB, but the reverse type shows reactions with both A and B cells?
A. Rouleaux formation
B. Cold autoantibody
C. Acquired B antigen
D. Group AB with cold alloantibody
Answer: B. Cold autoantibody
Explanation: Cold autoantibodies can cause reverse typing to appear falsely positive due to
nonspecific agglutination.
,4. Which antibody is commonly associated with delayed hemolytic transfusion
reactions and is often undetectable during initial screening?
A. Anti-E
B. Anti-Jkᵃ
C. Anti-M
D. Anti-Leᵃ
Answer: B. Anti-Jkᵃ
Explanation: Kidd antibodies (especially Jkᵃ) are often weak or transient but can cause severe
delayed hemolytic reactions.
5. Which antibody is most likely to be clinically insignificant?
A. Anti-Fyᵃ
B. Anti-Leᵃ
C. Anti-K
D. Anti-E
Answer: B. Anti-Leᵃ
Explanation: Lewis antibodies like anti-Leᵃ are typically IgM, do not cause HDFN, and are
considered insignificant for transfusion purposes.
6. What is the function of LISS (Low Ionic Strength Solution) in antibody
screening?
A. Enhances IgM detection
B. Reduces zeta potential and enhances IgG uptake
C. Inactivates complement
D. Removes autoantibodies
Answer: B. Reduces zeta potential and enhances IgG uptake
Explanation: LISS facilitates antibody binding by decreasing the ionic strength of the testing
environment, enhancing IgG detection.
7. Which of the following blood components should be irradiated for a neonate
undergoing intrauterine transfusion?
,A. Platelets only
B. RBCs only
C. All components
D. Cryoprecipitate
Answer: C. All components
Explanation: Irradiation of cellular components is mandatory to prevent transfusion-associated
graft-versus-host disease (TA-GVHD) in immunocompromised patients.
8. A patient with a warm autoantibody is being crossmatched. What is the best
strategy to ensure safe transfusion?
A. Transfuse ABO-compatible blood without testing
B. Use cold panel to rule out antibodies
C. Identify any underlying alloantibodies and issue least incompatible blood
D. Wait for autoantibody to clear
Answer: C. Identify any underlying alloantibodies and issue least incompatible blood
Explanation: Warm autoantibodies can mask alloantibodies. Adsorption techniques should be
used to rule out clinically significant antibodies.
9. Which of the following conditions is most commonly associated with anti-I?
A. Infectious mononucleosis
B. Mycoplasma pneumoniae infection
C. Pregnancy
D. Sickle cell disease
Answer: B. Mycoplasma pneumoniae infection
Explanation: Anti-I is a cold-reactive autoantibody linked to Mycoplasma infections and can
cause cold agglutinin disease.
10. What is the primary reason for performing an antibody screen in
pretransfusion testing?
A. Detect antibodies to ABO antigens
B. Detect unexpected alloantibodies
C. Determine Rh status
D. Confirm crossmatch compatibility
, Answer: B. Detect unexpected alloantibodies
Explanation: Antibody screens aim to detect non-ABO antibodies (usually IgG) that may cause
transfusion reactions or HDFN.
11. What is the most appropriate confirmatory test to determine weak D status?
A. Indirect antiglobulin test
B. Direct antiglobulin test (DAT)
C. Enzyme treatment
D. Adsorption and elution
Answer: A. Indirect antiglobulin test
Explanation: Weak D is tested by incubating red cells with anti-D, then adding AHG (indirect
antiglobulin phase). It's used to detect reduced D antigen expression.
12. Which antibody is most commonly associated with severe hemolytic disease of the fetus
and newborn (HDFN)?
A. Anti-M
B. Anti-K
C. Anti-Leᵇ
D. Anti-P1
Answer: B. Anti-K
Explanation: After anti-D, anti-K is the most severe cause of HDFN, as it can suppress fetal
erythropoiesis in addition to causing hemolysis.
13. A cord blood sample shows a positive DAT. Which of the following is the most likely
cause?
A. Maternal anti-D
B. Infant anti-A
C. Fetal anti-B
D. Maternal anti-Leᵃ
Answer: A. Maternal anti-D
Explanation: A positive DAT in a newborn most often indicates maternal IgG antibodies (like
anti-D) crossing the placenta and coating fetal red cells.
14. Which blood group system shows dosage effect most strongly?
