SBB ASCP EXAMINATION TEST 2026
QUESTIONS WITH ANSWERS GRADED A+
◉ List several high incidence blood group antigens. Answer: Kp(b)
k
Js(b)
Lu(b)
I
U
These antigens are found in 99% of the population
◉ What 4 RBC antigens are not fully expressed at birth. Answer: A
B
I
P(1)
Lewis
Lutheran
◉ What is sensitization? Answer: Attachment of antibodies to antigen on
a red cell
,◉ Why should serum separator tubes not be used for blood bank testing?
Answer: The gel can contaminate the red blood cells during sampling
and can cause false-positive test results.
◉ What is the terminal sugar on the B antigen? Answer: D-galactose
◉ What is the terminal sugar on the A antigen? Answer: N-
acetylgalactosamine.
◉ Which races have the higher percentage of group B? Answer: Blacks
and Chinese.
◉ When might anti-A,B be used? Answer: Anti-A,B is no longer used
for routine typing but some labs use it for confirmatory typing of Group
0 red cell units.
◉ What might cause the naturally-occurring isoagglutinins to be
decreased in titer or missing? Answer: Hypo- or agammaglobulinemia,
leukemia, or the age of the patient.
Babies do not have detectable levels of naturally-occurring
isoagglutinins in their plasma/serum until 3-6 months of age and titers
decrease in the elderly.
,◉ What are lectins? Answer: Extracts from plant seeds or animals that
have antibody-like activity. For example, Dolichos biflorus agglutinates
A1 cells and Ulex europeus reacts with the H determinant.
◉ Why is anti-A1 not detected in an antibody screen? Answer: Antibody
screening cells are group 0. Anti-A1 only reacts with A1 cells.
◉ How is anti-A1 usually discovered? Answer: By an ABO discrepancy
in which there is unexpected agglutination of Ai cells in the reverse
grouping of a group A.
◉ What group of blood should be transfused to a patient with anti-A1?
Answer: If the antibody is reactive at 37°C, cells lacking the A1 antigen
(subgroup of A or group 0) should be transfused.
Anti-A1 that only reacts below 30°C is not considered clinically
significant. In actual practice, some blood banks would provide
subgroup of A or group 0 blood without testing the thermal range of the
Anti-A1. The laboratory's
standard operating procedures (SOP) should be followed.
◉ How can rouleaux interfere with blood bank tests? Answer: Rouleaux
cause false-positive reactions with all cells mixed witth the serum.
Rouleaux are due to a serum protein abnormality and are usually seen in
patients with multiple myeloma.
, ◉ While retyping a group B trauma patient, the technologist observes
mixed field agglutination with anti-B. Typing at the lime of admission
showed 4+ agglutination with anti-B. What might have caused this
change in
reactivity? Answer: The patient might have been transfused with a large
volume of group 0 ABCs. The transfusion history should be
checked.
◉ How does the acquired B antigen usually react? Answer: It typically
agglutinates strongly with anti-A and weakly with anti-B, and the serum
contains strong anti-B.
◉ How might transfusion of non-group specific blood affect subsequent
blood grouping result? Answer: Donor cells are detectable in the
recipient for up to 4 months, the life span of the RBC. Front grouping
reactions may be weak or mixed-field if group 0 cells have been
transfused to a patient of another group. Passive anti-A
and/or anti-B might be detected in the reverse grouping if large volumes
of group 0 RBCs or platelets have been transfused to a patient of another
group. These products contain some plasma and naturally-occurring
isoagglutinins
◉ How might agammaglobulinemia or leukemia affect a patient's blood
grouping? Answer: The naturally-occurring isoagglutinins might be
weak or missing. With leukemia, certain antigens may also be
weak or missing.
QUESTIONS WITH ANSWERS GRADED A+
◉ List several high incidence blood group antigens. Answer: Kp(b)
k
Js(b)
Lu(b)
I
U
These antigens are found in 99% of the population
◉ What 4 RBC antigens are not fully expressed at birth. Answer: A
B
I
P(1)
Lewis
Lutheran
◉ What is sensitization? Answer: Attachment of antibodies to antigen on
a red cell
,◉ Why should serum separator tubes not be used for blood bank testing?
Answer: The gel can contaminate the red blood cells during sampling
and can cause false-positive test results.
◉ What is the terminal sugar on the B antigen? Answer: D-galactose
◉ What is the terminal sugar on the A antigen? Answer: N-
acetylgalactosamine.
◉ Which races have the higher percentage of group B? Answer: Blacks
and Chinese.
◉ When might anti-A,B be used? Answer: Anti-A,B is no longer used
for routine typing but some labs use it for confirmatory typing of Group
0 red cell units.
◉ What might cause the naturally-occurring isoagglutinins to be
decreased in titer or missing? Answer: Hypo- or agammaglobulinemia,
leukemia, or the age of the patient.
Babies do not have detectable levels of naturally-occurring
isoagglutinins in their plasma/serum until 3-6 months of age and titers
decrease in the elderly.
,◉ What are lectins? Answer: Extracts from plant seeds or animals that
have antibody-like activity. For example, Dolichos biflorus agglutinates
A1 cells and Ulex europeus reacts with the H determinant.
◉ Why is anti-A1 not detected in an antibody screen? Answer: Antibody
screening cells are group 0. Anti-A1 only reacts with A1 cells.
◉ How is anti-A1 usually discovered? Answer: By an ABO discrepancy
in which there is unexpected agglutination of Ai cells in the reverse
grouping of a group A.
◉ What group of blood should be transfused to a patient with anti-A1?
Answer: If the antibody is reactive at 37°C, cells lacking the A1 antigen
(subgroup of A or group 0) should be transfused.
Anti-A1 that only reacts below 30°C is not considered clinically
significant. In actual practice, some blood banks would provide
subgroup of A or group 0 blood without testing the thermal range of the
Anti-A1. The laboratory's
standard operating procedures (SOP) should be followed.
◉ How can rouleaux interfere with blood bank tests? Answer: Rouleaux
cause false-positive reactions with all cells mixed witth the serum.
Rouleaux are due to a serum protein abnormality and are usually seen in
patients with multiple myeloma.
, ◉ While retyping a group B trauma patient, the technologist observes
mixed field agglutination with anti-B. Typing at the lime of admission
showed 4+ agglutination with anti-B. What might have caused this
change in
reactivity? Answer: The patient might have been transfused with a large
volume of group 0 ABCs. The transfusion history should be
checked.
◉ How does the acquired B antigen usually react? Answer: It typically
agglutinates strongly with anti-A and weakly with anti-B, and the serum
contains strong anti-B.
◉ How might transfusion of non-group specific blood affect subsequent
blood grouping result? Answer: Donor cells are detectable in the
recipient for up to 4 months, the life span of the RBC. Front grouping
reactions may be weak or mixed-field if group 0 cells have been
transfused to a patient of another group. Passive anti-A
and/or anti-B might be detected in the reverse grouping if large volumes
of group 0 RBCs or platelets have been transfused to a patient of another
group. These products contain some plasma and naturally-occurring
isoagglutinins
◉ How might agammaglobulinemia or leukemia affect a patient's blood
grouping? Answer: The naturally-occurring isoagglutinins might be
weak or missing. With leukemia, certain antigens may also be
weak or missing.
